Calcium Supplements Review

Find the Best Calcium Supplement. Tests and Reviews of Popular Calcium Supplements & CL's Top Picks.

Medically reviewed and edited by Tod Cooperman, M.D.

Last Updated: 10/26/2020 | Initially Posted: 11/23/2019Latest Update: Reducing Risk of Fractures & Falls With Milk, Cheese and Yogurt?

Table of Contents

Summary

· Health benefits of calcium: It is important that you get an adequate amount of calcium, as it is essential to maintaining your bones and plays critical roles in nerve transmission, muscle contraction, and your cardiovascular system. In fact, getting sufficient calcium each day (1,000 to 1,200 mg for adults) may decrease your risk of dying from cardiovascular disease. For details, see What It Does.

· Good sources of calcium: You may already get enough calcium in your diet from dairy, beans, green-leafy vegetables, and other foods. In fact, with the exception of girls ages 9 to 18, most individuals take in enough calcium from what they eat. For the recommended intakes of calcium and to learn how much you may already get from food, see What to Consider When Using.

· Safety and side effects of calcium supplements: If you're not getting enough calcium from your diet, supplements can help. Calcium supplements have shown some modest benefits for postmenopausal women, particularly those on hormonal therapy after hysterectomy (see What It Does). But be careful! Calcium from supplements may increase the risk of heart attack and stroke if you get too much from supplements (generally over 1,000 mg per day) or if you already get at least 805 mg of calcium from your diet. Calcium supplements also increase the risk of kidney stones in postmenopausal women. See Concerns and Cautions for more information.

· How much calcium to take? Since you can't absorb more than about 500 mg of calcium at a time, consider limiting intake from supplements to 500 mg or less at a time and, certainly, no more than 1,000 mg total per day. Also, be sure you are getting enough vitamin D, as it is necessary for your body to absorb and utilize calcium from both foods and supplements and may reduce some of the risks associated with calcium supplements. Vitamin D is in many of the supplements tested in this Review. For extensive information about vitamin D, see the Vitamin D Supplements Review.

· Which calcium supplement is best? This depends, first, on your particular needs. Use the Results table below to narrow in on products which provide the right amount of calcium and other ingredients to meet your needs. Be sure focus on products which have been approved by ConsumerLab.com because not all supplements are properly made and live up to their ingredient claims. Then compare prices in the last column of the table -- you can get some good products for just pennies a day. Taking these factors into consideration, ConsumerLab selected several Top Picks for calcium supplements.

· When to take calcium? If your calcium supplement includes vitamin D and/or vitamin K, take it with the meal that contains most fats and oils, as this may increase absorption of those vitamins. Otherwise, you can take calcium with any meal, but don't take it at the same time that you take other mineral supplements as the calcium may reduce their absorption. If you are taking calcium citrate, you may be able to take it with or without food. Follow the directions on the supplement.

What It Is:

Calcium is an essential mineral for the body and is one of the most popular dietary supplements in the U.S. Calcium can be obtained exclusively from food. Many types of calcium supplements are available and in an increasing variety of delivery forms including tablets, caplets, softgels, syrups, chewable tablets, softchews, gummies, antacids, and calcium-fortified foods and juices. The most common and generally least expensive form of calcium is calcium carbonate. Other types include calcium malate, calcium citrate malate, calcium lactate and calcium gluconate. The forms vary somewhat in how they are best used (see ConsumerTips™ for discussion of different forms).

(See separate reviews of Vitamin D and Vitamin K, which are also important to bone health).

What It Does:

Bone Health and Fractures
Adequate calcium is critical for building and maintaining strong bones, where 99% of the mineral is found in the body. The rest is present in the blood, extracellular fluid, muscle and other tissues, where it plays a necessary role in vasodilation, muscle contraction, nerve transmission and glandular secretions.

In girls ages 9 to 13, regular supplementation with calcium and vitamin D has been shown to significantly increase bone density and bone strength (measured in arms and legs) compared to placebo (Greene, Osteoporosis Int 2011).

Calcium supplements, taken with vitamin D, appear to at least modestly protect against osteoporosis in postmenopausal women. However, a review of studies in which calcium (500 to 1,500 mg/day) and vitamin D (100 to 1,000 IU/day ) were given to women being treated for breast cancer found no benefit in preventing bone mineral density loss (Datta, Crit Rev Onc Heme 2013). This is unfortunate, as women receiving breast cancer therapy are at increased risk of osteoporosis.

Studies have not been consistent as to whether calcium and vitamin D reduce the risk of fractures. For example, a long-term study in postmenopausal women found that those receiving 500 mg of calcium (from calcium carbonate) and 200 IU of vitamin D3 twice daily slightly reduced their risk of hip fracture compared to those receiving placebo, but the reduction was not statistically significant (Jackson, NEJM 2006). However, the same study found that when the calcium/vitamin D supplement was given to women receiving hormonal therapy (after hysterectomy), the risk of hip fracture was reduced by half compared to women who did not receive the supplementation (Robbins, Menopause 2013.)

Supplementing with calcium and vitamin D may reduce the risk of hip fracture in middle-aged and older women who follow a vegan diet, according to a study that followed 34,542 women and men ages 42 or older (average age 63) for an average of 8 years. Women who followed a vegan diet and did not take supplemental calcium and vitamin D had about three times the risk of hip fracture compared to non-vegetarians, while women following a vegan diet who took both calcium and vitamin D (average dose 660 mg of calcium and 540 IU (13.5 mcg) of vitamin D) did not have an increased risk of hip fracture compared non-vegetarians. There was no increased risk of hip fracture in men following a vegan diet with or without calcium/vitamin D supplementation (Thorpe, Am J Clin Nutr 2021).

Overall, studies have not shown supplementation with calcium, vitamin D, or the combination to significantly reduce the risk of hip fractures in older, community-dwelling (i.e., not in nursing or hospital facility) adults, according to an analysis of 33 clinical trials. A potential weakness of this analysis is that some of the studies did not assess baseline levels of vitamin D, i.e., whether or not patients were deficient to start (Zhao, JAMA 2017). Consistent with these earlier findings, the use of calcium supplements was not associated with a reduced incidence of bone fracture in women who were pre-menopause or early peri-menopause even though it was associated with a slower rate of decline in bone mineral density (measured at the lumbar spine and neck of the femur, i.e., the thigh bone) -- particularly in pre-menopausal women. The study involved women aged 42 to 52 years at enrollment who were followed for 10 years (Bailey, JBMRPLUS 2019).

Interestingly, a large study among elderly residents of long-term care facilities in Australia with adequate vitamin D found that increasing daily calcium intake from foods to recommended levels, along with a modest increase in dietary protein, decreased the risk of fractures and falls. The study involved 7,195 men and women (average age 85) living in any of 60 long-term care facilities. Approximately half of the facilities served their usual menu (the control diet -- providing a total of 700 mg calcium, which is below the recommended daily intake of 1,200 mg for adults of this age, and 58 grams of protein per day), while the other half of the facilities served the standard diet with additional milk, yogurt, and cheese (providing a total of 1,152 mg of calcium and 69 grams of protein per day). After three months, there was an 11% lower risk of falls in the facilities that served the additional dairy, and after five months, a 33% lower risk of all fractures and a 46% lower risk of hip fractures, compared to the facilities that served the control diet. The findings emphasize the importance of getting adequate calcium from the diet. In addition, although the control diet provided an amount of protein close to the recommended intake for sedentary adults (about 60 grams per day for a 150 lb. adult), there is evidence that older adults may require higher protein intakes to maintain muscle, which may also reduce the risk of falls (Juliano, BMJ 2021).

For bone health, everyone should try to get the recommended daily intake of calcium from their diets. If your diet is not adequate, it would seem prudent and safe -- particularly for girls ages 9 to 13 and women from the time of pre-menopause and after -- to supplement with moderate amounts of calcium (no more than 300 mg to 500 mg per serving).

Cancer and Mortality
A large 4-year placebo-controlled study of post-menopausal women in rural Nebraska found that 1,500 mg of calcium (500 mg from calcium carbonate taken three times daily) and 2,000 IU of vitamin D3 daily did not significantly lower the risk of cancer overall or specific cancers, including colon, ovarian, breast, lung or skin (Lappe, JAMA 2017). It should be noted that most women in the study were not lacking calcium intake, with average daily calcium intake from foods of 676 mg and many averaging another 500 mg daily from their own supplements, which they were allowed to continue. Another, a large, study in the U.S. found that daily supplementation with calcium (1,200 mg) and/or vitamin D3 (1,000 IU) for 3 to 5 years did not reduce the risk of developing new precancerous colorectal polyps (adenomas) among men and women who had adenomas removed in the past. There was no statistically significant difference in the occurrence of adenomas between those who were or were not given the supplements. On average, without the study supplements, dietary intake of calcium in the study was somewhat inadequate (about 600 to 700 mg daily, but the vast majority of women had adequate levels of vitamin D (Baron, NEJM 2015). (Note: These findings may not apply to people with vitamin D levels which are inadequate, i.e., under 20 ng/mL). Disturbingly, over six to ten years after this study, the risk of precancerous polyps was 165% and 281% higher, respectively, among those who had taken the calcium or calcium plus vitamin D supplements compared to those who had taken no supplement. Supplementation with vitamin D alone did not increase the risk of developing polyps. The increase in risk was greatest among women and current smokers. Bear in mind that calcium from the diet (such as from dairy products) is not associated with an increased risk of polyps (Crockett, Gut 2018).

COVID-19 (Coronavirus)
Very preliminary studies indicate that calcium levels fall in patients with COVID-19, the disease caused by the coronavirus SARS-CoV-2. For example, 75% of hospitalized patients in a study in Wuhan China had low blood levels of calcium (hypocalcemia) on admission (i.e., below, 2.20 mmol/L or 8.8 mg/dL) and this correlated with worse values on other biologic markers of disease. Those with levels at or below 2.0 mmol/L were more likely to have organ injury and to die over the 28-day study period (Sun, Research Square 2020 — preprint, not peer-reviewed). A review of the records of 15 patients hospitalized for COVID-19 at the Mayo Clinic in Arizona from late March to early April showed that those with severe cases also experienced progressive declines in calcium, as well as albumin, while those with mild cases did not. Patients with severe cases also had high levels of unbound fatty acids, which other research suggests may cause injury to organs. Calcium and, to a lesser extent, albumin, are effective at binding up these fatty acids and the researchers hypothesized that supplementing with calcium and albumin during COVID-19 hospitalization may, consequently, reduce organ failure and the need for intensive care. However, clinical studies are necessary to prove this (El-Kurdi, Gastroenterol 2020).

Mortality and Cardiovascular Disease
A study of white postmenopausal women found that calcium supplementation was associated with a 3.8% reduced risk of death over a 22 year period (Mursu, Arch Int Med 2011). However, the benefit did not exist when more than 900 mg of calcium per day was taken from supplements (see Concerns and Cautions for potential risks of calcium supplementation). Similarly, a study in Canadian adults found that taking daily supplements containing up to 1,000 mg of calcium was associated with a 22% reduced risk of death in women (but not men) over the 10-year study period compared to those not taking a calcium supplement. At doses of 1,000 mg or more, no reduction in death was found for women or men (Langsetmo, J Clin Endocrinol Metab 2013).

Looking specifically at the risk of death from cardiovascular disease, a large, 12-year study of men and women found that deaths from cardiovascular disease decreased with increasing total calcium intakes (from all sources combined) up to approximately 1,200 mg per day (which is the RDA for women and all older adults) (Xiao, JAMA Intern Med 2013).

Weight Loss
While early studies seemed promising, hopes that increased calcium intake could aid weight loss have largely been dashed by subsequent studies. Exceptional health claims made in recent years about coral calcium, such as the ability to cure cancer, are unsubstantiated. In fact, some evidence suggests that calcium intake may be associated with an increased risk of prostate cancer (Schwartz, Canc Epidemiol Biomarkers 2012) (See Cautions and Concerns).

Age-Related Macular Degeneration (AMD)
Higher consumption of calcium from foods has been associated with lower risk of AMD, while there is mixed evidence regarding the effects of calcium from supplements. A study in Australia that followed over 2,000 men and women (age 50 and older) for 15 years found that those who reported the lowest calcium intake from foods (< 565 mg per day) had a modestly higher risk of developing late (i.e., advanced) age-related macular degeneration (AMD) after 10 to 15 years than those who reported consuming the highest amount of calcium from foods (> 1,247 mg per day) (Gopinath Br J Nutr 2014). With regard to calcium intake from supplements, a study among over 3,000 men and women found that, after age 67, those who reported consuming more than 800 mg of calcium per day from supplements and/or antacids were 164% more likely to be diagnosed with AMD than those who did not take calcium supplements (Kakigi, JAMA Ophthalmol 2015). On the other hand, analysis of data from the Age-Related Eye Disease Study (AREDS) found that women over 65 with high intakes of calcium (averaging about 1,400 mg/day) from supplements had, over the following 10 years, a statistically significant 30% lower risk of developing neovascular ("wet") AMD than those who did not take supplements. They also had a 22% lower risk of late AMD, although this was not deemed statistically significant, and there was no risk reduction with regard to atrophic ("dry") AMD. High intake of calcium from food (about 1,200 mg or more per day) by men and women was associated with a 27% lower risk of late AMD and 20% lower risk of atrophic AMD compared to low intake (about 600 mg or less per day) (Tisdale, JAMA Opthal 2019). Note that none of these studies prove a cause-and-effect relationship, as they were not clinical trials.

Other Uses
Other possible benefits of calcium supplementation include reducing PMS symptoms and slightly lowering blood pressure.

Quality Concerns and Tests Performed:

Like other supplements, neither the FDA nor any other federal or state agency routinely tests calcium supplements for quality prior to sale. However, quality issues can include the following:

· Labeled Amount -- Does the product really contain the labeled amount of calcium (and, if applicable, other key ingredients such as vitamin D, vitamin K, magnesium, and boron)? While calcium is an inexpensive raw material, it can be bulky, making the formulation of calcium supplements complex. If not manufactured properly, products may not "pack in" the labeled amount of calcium.

· Purity -- Many sources of calcium naturally contain heavy metals such as lead, arsenic and cadmium. In children, infants, and fetuses, even low levels of lead can adversely affect neurobehavioral development and cognitive function. In adults, lead at somewhat higher levels can cause elevated blood pressure, anemia, and adversely affect the nervous and reproductive systems. Lead is of particular concern during pregnancy as the mother can deliver it to the fetus. Arsenic is a carcinogen and can damage organs. Cadmium is a probable carcinogen (i.e., cancer-causing agent), can be toxic to the kidneys, can soften the bones, causing bone pain, and may affect fetal development.

· Ability to Break Apart for Absorption -- For a tablet to be most useful, it must fully disintegrate prior to leaving the stomach, delivering its contents for absorption in the gut. Some tablets are not properly made and can pass through your body completely or partially intact, depriving you of its ingredients. Remnants of such products are sometimes found in the stool. This happens, for example, when a tablet is too tightly compressed (too "hard") or is too thickly coated.

ConsumerLab.com, as part of its mission to independently evaluate products that affect health, wellness, and nutrition, purchased supplements containing calcium (including combinations with vitamin D, vitamin K, magnesium, and/or boron) sold in the U.S. and tested them to determine whether they 1) possessed the claimed amount of calcium, boron, magnesium, and vitamins D and/or K, 2) were able to disintegrate fully to be available for absorption and 3) were free from unacceptable levels of lead, cadmium, and arsenic (see Testing Methods and Passing Score).

What CL Found:

All of the products tested were found to contain their claimed amount of calcium, none were contaminated with heavy metals, and all tablets and caplets were found to disintegrate properly. However, two products were Not Approved because they failed to meet other quality criteria, as discussed below. These failures were each confirmed in a second independent laboratory.

· Natural Vitality Natural Calm Plus Calcium - Raspberry-Lemon Flavor contained its claimed amounts of calcium and magnesium, but contained a bit less vitamin D than claimed (22.1 IU instead of 35 IU) and more than double its listed amount of boron (198.5 mcg instead of 88.3 mcg) per teaspoon of powder. Although this suggests a quality control problem, these discrepancies do not pose a safety issue as the listed amounts are relatively small to start: The daily requirement for vitamin D is 400 IU to 800 IU, and although there is no daily requirement for boron -- because it is not essential -- most people get about 1,000 mcg to 10,0000 mcg from their diets and the daily upper tolerable intake level for adults is even higher: 17,000 to 20,000 mcg (National Academies). (Note: In 2017 CL tested a magnesium-only version of Natural Calm of the same flavor and it passed testing.)

· Thorne Basic Bone Nutrients contained its claimed amounts of calcium and magnesium, but only 69.7% of its claimed vitamin D (348.5 IU vs. 500 IU) and just 2.2% of its vitamin K (1 mcg versus 45 mcg). These are major discrepancies, particularly for vitamin K, indicating that one should not rely on this product for either of these nutrients.

Thirteen of the 15 products that ConsumerLab.com selected for testing met all quality criteria, as did five products tested through ConsumerLab.com's voluntary Quality Certification Program.

Calcium per pill or teaspoon
Be aware that the amount of calcium in a single pill or teaspoon of a supplement varied tremendously across products, from as little as 41.7 mg (Standard Process Calcium Lactate) to as much as 600 mg in CVS Health Calcium in a tablet of each. Most products provide 200 mg to 300 mg of calcium per pill (or 125 mg per gummy or chewable for kids), which is more in line with what are safe and effective doses to boost calcium intake to recommended levels. If needed, one can take more than one per day but do not take more than 500 mg in a single serving (see How to Take).

Cost
Calcium is generally an inexpensive supplement, costing as little as 3 to 5 cents per 250 mg, as calculated and shown in the graph below. Extra ingredients raise the cost, but not necessarily by that much. For example, GNC Calcimate Complete provides calcium, magnesium, boron, and vitamins D and K for just 13 cents per 2 caplets providing 400 mg of calcium -- working out to just 8 cents per 250 mg of calcium. Cost tends to be higher with special formulations, such as gummies, chewables, and powders. The most expensive approved product for getting calcium was Standard Process Calcium Lactate, costing 56 cents per 250 mg of calcium from six small pills.

Top Picks:

Among Approved products, ConsumerLab.com chose several as Top Picks (see below). To be a CL Top Pick, a calcium supplement had to pass ConsumerLab's tests of quality, provide a form of calcium with good bioavailability at a reasonable dose, and offer good value (i.e., a favorable price). In combination products, amounts of other ingredients were also considered.

Keep in mind that you can't absorb more than about 500 mg of calcium at a time, so it's best to limit calcium intake from supplements to about 200 mg to 500 mg at a time, and certainly, no more than 1,000 mg total per day, as there are risks associated with getting more than this amount from supplements (See Concerns and Cautions). Also remember that the required daily intake for calcium (1,000 mg to 1,200 mg for adults) includes calcium from all sources, so be sure to factor in calcium you are getting from foods and over-the-counter products such as antacids when deciding how much calcium you want from a supplement.

As discussed in What to Consider When Buying, calcium citrate and calcium malate may be better absorbed and more effective than calcium carbonate if you have low levels of stomach acid (which can occur with some drugs).

Calcium Only: Solaray Calcium Citrate is our Top Pick in the Calcium Only category. It provides 250 mg of calcium (from calcium citrate) per capsule for just 5 cents. Each capsule provides about 20% to 25% of the adult daily requirement for calcium. The citrate form is a generally well absorbed and can be taken with or without food, unlike calcium carbonate which must be taken with a meal. Just be aware that the capsules are fairly large.

Calcium and Vitamin D: Bayer Citracal Petites provide 400 mg of calcium (from calcium citrate) and 500 IU of vitamin D per 2-caplet serving for 16 cents. This is a little less than half the daily requirement for calcium, as well as enough vitamin D to boost someone who's a little low in vitamin D. Note that, despite the product name, the caplet size is large, although narrow. If you live in Canada, Webber Naturals Calcium Citrate Vitamin D3 is also Top Pick in this category, providing 300 mg of calcium (from calcium citrate) and 200 IU of vitamin D for 9 cents.

Children's Calcium and Vitamin D: Our Top Pick, although pricey, is Yummi Bears Calcium + D3, which provide 375 mg of calcium (from tricalcium phosphate) and 300 IU of vitamin D3 per 3 gummy bears for 42 cents. (Although not tested this year, a less expensive option is L'il Critters Calcium & D3, which was tested and approved in 2017, and provides 200 mg of calcium (from tricalcium phosphate) and 220 IU of vitamin D3 per 2 gummies for about 13 cents currently). We are not big fans of gummies for several reasons, including the fact that they may be over-consumed as candy, resulting in overdosing. But if gummies are the only way to get a kid who otherwise won't get enough nutrients from foods or non-sweetened supplements to meet the daily requirements, they are a reasonable option (just be sure to store in a safe place away from little hands!)

Calcium and Magnesium: Puritan's Pride Chelated Calcium Magnesium Zinc provides 333 mg of calcium (from calcium carbonate and calcium gluconate) and 133 mg of magnesium (from magnesium oxide and magnesium gluconate) per caplet for just 5 cents. Be aware that this product also contains zinc (8 mg per caplet, which is about the adult daily requirement). The Puritan's Pride product actually suggests taking 3 caplets daily, but this would put you just over the upper tolerable intake level for magnesium from supplements and probably give you a lot more zinc than you want.

Calcium, Magnesium, and Boron: Solgar Calcium Magnesium Plus Boron provides 333 mg of calcium (from carbonate, gluconate, and citrate forms), 133 mg of magnesium (oxide, citrate, and gluconate forms), and 1,000 mcg of boron (citrate form) per tablet for 7 cents. Note that taking the suggested dose of 3 tablets daily would put you over the upper tolerable intake level for magnesium from supplements. Be aware that when a product shows a combination of forms for a mineral, the forms are listed in order of magnitude and it's possible that the majority of the mineral is from the first form which, in this case for calcium, is carbonate, and for magnesium is oxide — both are forms that may not be absorbed as well as the citrate form of each. 

Calcium, Vitamin D and Vitamin K: We didn't test any products in this category this year. However, if this is a combination you want, Viactiv Calcium Plus D, which passed our tests in 2017, provides these three nutrients. However, the current Viactiv formula provides 650 mg of calcium (from calcium carbonate) per chew, which is more than the 500 mg it contained in 2017 and more than is generally recommended at one time. If you use Viactiv, it would seem preferable to divide the chew in half, taking each half at least three hours apart during the day - if you even need to get that much calcium from a supplement daily. Each full chew also provides 500 IU vitamin D3 and 40 mcg vitamin K1 (about half the recommended intake for women and one-third the recommended intake for men) for about 13 cents per soft chew. As noted in ConsumerTips, supplements that provide calcium from calcium carbonate should be taken with a meal for best absorption, as is the case with Viactiv even though it is a chew.

Calcium, Vitamin D, and Magnesium: All three of the products tested in this category use calcium carbonate and magnesium oxide, which are less bulky than other forms (keeping pill size down) but may not be absorbed as well. Among the three, however, our Top Pick is Puritan's Pride Calcium Magnesium Vitamin D3 as it provides a lower dose of calcium (333 mg) per caplet, for 7 cents, allowing you to take more if necessary, while the others provide 500 mg (in Rainbow Light) or 600 mg (in Caltrate) per pill.

Children's Products Containing Calcium, Vitamin D, and Magnesium: Similar to the adult products in this category, both of the products that we tested for children primarily use calcium carbonate and magnesium oxide. Both provide the same amounts of calcium (250 mg) and vitamin D (200 IU) and similar amounts of magnesium per two chewable tablets. Our Top Pick is Pioneer Children's Cal Mag & D as it is less expensive (15 cents) than Bluebonnet Rainforest AnimalZ (23 cents). Pioneer is vanilla flavored while Bluebonnet is cocoa flavored.

Vitamin D, Calcium, Magnesium, and Boron: Vitalite Now! Calcium & Magnesium Plus provides significant amounts of calcium (250 mg), magnesium (125 mg), and boron (1,000 mcg) in each capsule, as well as a modest amount of vitamin D (100 IU). Although the label suggests taking four capsules daily (for a relatively high daily cost of 48 cents), fewer capsules would be sufficient for most people to reach the daily requirements. The source of calcium is a list of nearly every form of calcium, but carbonate is the first and may be the main form, so it is important to take this product with a meal.

Calcium, Vitamin D, Magnesium, and Vitamin K: Only one of two products in this category passed our tests: New Chapter Bone Strength Take Care. However, due to its high cost, it is not a Top Pick. The suggested daily serving of 3 tablets provides 1,000 IU of vitamin D, 770 mg of calcium, 80 mcg of vitamin K from K1 and K2, and a modest amount of magnesium. It is best to break this into two or three servings to be taken with meal during the day, as 770 mg of calcium is too much to take at one time. This is a relatively expensive product at 96 cents per day and, considering that there is no compelling research showing superiority of algae-based calcium or magnesium, you can easily get these same ingredients for less by purchasing the ingredients separately.

Calcium, Vitamin D, Magnesium, Boron, and Vitamin K: Both of the products that we tested in this category, GNC Calcimate and Jarrow Formulas Bone Up, provide significant amounts of calcium, vitamin K, and boron. What sets them apart is the amount of magnesium they provide, with Jarrow providing several times as much as GNC as well as a daily dose of vitamin D (1,000 IU) that is closer to the adult requirement (600 IU to 800 IU) than GNC's 2,000 IU. Although it costs more (51 cents daily for 6 capsules versus 25 cents daily for 4 caplets), Jarrow Formulas Bone Up is our Top Pick for this category. With either product, consider cutting the suggest dose in half if you are just trying to boost your intake of these nutrients and not trying to fulfill the majority of the daily requirements from a supplement. By the way, Jarrow Formulas Bone-Up, provides calcium as StimuCal microcrystalline hydroxyapatite —see What to Consider When Buying for more about this ingredient.

Test Results by Product:

Listed below are the test results for 20 supplements containing calcium. Products are grouped according to the ingredients they contain, and there are two groups of children's supplements. Within each group, products are listed alphabetically. ConsumerLab.com selected 15 of these products. Five other products (each indicated with a CL flask) were tested at the request of their manufacturers/distributors through ConsumerLab.com's voluntary Quality Certification Program and are included for having passed testing.

Shown for each product are the claimed amount and form of the tested ingredient(s), serving size recommended on its label, pill size, and cost per 250 mg of calcium. Products listed as "Approved" met their label claims and ConsumerLab.com's quality criteria (see Passing Score). The full list of ingredients (including special dietary designations) is available for each product in the last column.

Jump to results by ingredient:

· Calcium Only

· Calcium & Vitamin D

· Children's Calcium & Vitamin D

· Calcium & Magnesium

· Calcium, Magnesium & Boron

· Calcium, Vitamin D & Magnesium

· Children's Calcium, Vitamin D & Magnesium

· Calcium, Magnesium, Boron & Vitamin D

· Calcium, Vitamin D, Vitamin K & Magnesium

· Calcium, Magnesium, Boron, Vitamin D & Vitamin K

Results of ConsumerLab.com Testing of CALCIUM SUPPLEMENTS

(INCLUDING COMBINATIONS WITH MAGNESIUM, BORON, VITAMIN D AND/OR VITAMIN K)

(Click arrows or swipe left or right to see all columns)

Approval Statusⓘ

Product Name

Claimed Amount of and Form of Calcium, Magnesium, Boron, Vitamin D & Vitamin K Per Servingⓘ

Heavy Metalsⓘ

Suggested Daily Serving on Label

Pill Sizeⓘ

Cost for Suggested Serving

[Price per 250 mg Calcium]

Price

Notable Features

Full List of Ingredients Per Serving

Calcium Only:

APPROVED

CVS Health™ Calcium 600 mg

Dist. by CVS Pharmacy, Inc.

1 tablet

600 mg
(calcium carbonate)
✔

Heavy metals: Pass

Also tested for disintegrationⓘ

Adults, take one (1) tablet twice daily with food or as directed by your physician.

Large tablet

1 tablet

$0.08

[$0.03]
Lowest cost for calcium

$11.49/150 tablets

Precaution: Contains: soy.

1 tablet

Calcium (as Calcium Carbonate) 600 mg.

Other Ingredients: Microcrystalline cellulose, acacia, maltodextrin, croscarmellose sodium, hypromellose, titanium dioxide, more...

APPROVED

Top Pick

for calcium only

Solaray® Calcium Citrate 1,000 mg

Mfd. by Nutraceutical Corp.

$ Price Check

4 capsules

1,000 mg
(calcium citrate, carbonate)
✔

Heavy metals: Pass

Take four VegCaps daily with a meal or glass of water.

Large VegCap

4 capsules

$0.20

[$0.05]

$11.93/240 VegCaps

None.

4 capsules

Calcium (as Calcium Citrate [85%], Calcium Carbonate) 1,000 mg.

Other Ingredients: Vegetable cellulose capsule, magnesium stearate, watercress leaf, dandelion root and parsley leaf.

[Update (2/4/21): More recent labeling on this product claims "Calcium Citrate [up to 85%], Calcium Carbonate." According to correspondence from Solaray regarding this change "The percentage would be within 84-85 percent. We added the new language in case it varied slightly."]

Calcium & Vitamin D:

APPROVED

Top Pick

for calcium and vitamin D

Bayer Citracal® Petites

Dist. by Bayer HealthCare LLC

$ Price Check

2 caplets

400 mg
(calcium citrate)
✔

500 IU (12.5 mcg)
(D3)
✔

Heavy metals: Pass

Also tested for disintegrationⓘ

Adults: Take 1 serving (2 caplets) twice daily with or without food or as recommended by your physician, pharmacist, or health care professional.

Large coated caplet

2 caplets

$0.16

[$0.10]

$8.24/100 coated caplets

None.

2 caplets

Vitamin D (as cholecalciferol) 500 IU, Calcium (element) 400 mg.

Ingredients: Calcium citrate, polyethylene glycol, croscarmellose sodium, hydroxypropyl methylcellulose, magnesium silicate, more...

APPROVED

Kirkland Signature™ [Costco] Adult Gummies Calcium

Dist. by Costco Wholesale Corporation

2 gummies

500 mg
(tribasic calcium phosphate)
✔

1,000 IU (25 mcg)
(D3)
✔

Heavy metals: Pass

As a dietary supplement for adults, chew two (2) gummies daily, preferably with a meal.

Very large gumdrop shaped gummy

2 gummies

$0.22

[$0.11]

$12.99/120 gummies

USP® dietary supplement verified seal. No preservatives. No artificial flavors. No yeast or gluten. No lactose.

2 gummies

Calories 20, Total Carbohydrate 5 g, Total Sugars [Includes 3 g Added Sugars] 3 g, Vitamin D 25 mcg (1,000 IU), Calcium 500 mg, Phosphorus 230 mg.

Ingredients: Sugar, corn syrup, tribasic calcium phosphate, water, more...

APPROVED

Top Pick

for calcium and vitamin D

Webber Naturals® Calcium Citrate Vitamin D3

Dist. by WN Pharmaceuticals® Ltd.

1 tablet

300 mg
(calcium citrate)
✔

200 IU (5 mcg)
(D3)
✔

Heavy metals: Pass

Also tested for disintegrationⓘ

2-4 tablets daily, a few hours before or after taking other medications, or as directed by a physician.

Large tablet

1 tablet

$0.09

[$0.07]

$29.99/350 tablets

Free of artificial colours, preservatives or sweeteners; no dairy, sugar, wheat, gluten, yeast, soy, egg, fish, shellfish, salt, tree nuts or GMOs. Suitable for vegetarians.

1 tablet

Calcium (citrate) 300 mg, Vitamin D3 (cholecalciferol) 200 IU (5 mcg).

Non-medicinal Ingredients: Coating (carbohydrate gum, glycerin), croscarmellose sodium, vegetable grade magnesium stearate (lubricant).

Children's Products Containing Calcium & Vitamin D:

APPROVED

Top Pick

for children's calcium and vitamin D

Yummi Bears® Calcium + D3

Dist. by Hero Nutritionals, Inc.

$ Price Check

3 gummies

375 mg
(tricalcium phosphate)
✔

300 IU (7.5 mcg)
(D3)
✔

Heavy metals: Pass

As a dietary supplement, give each child three (3) bears per day.

Large bear shaped gummy

3 gummies

$0.42

[$0.28]

$12.61/90 gummies

Phosphorus 175 mg

Vegetarian approved. Free of: GMOs, gluten, yeast, wheat, dairy, eggs, soy, tree nuts, peanuts, shellfish, fish, gelatin, artificial flavors, artificial colors and artificial preservatives.

3 gummies

Calories 20, Total Carbohydrate 5 g, Sugars 4 g, Vitamin D (Vitamin D3 as cholecalciferol USP) 300 IU, Calcium (as tricalcium phosphate) 375 mg, Phosphorus (as tricalcium phosphate) 175 mg.

Other Ingredients: Organic tapioca syrup, natural cane sugar, more...

Calcium & Magnesium:

APPROVED

Top Pick

for calcium and magnesium

Puritan's Pride® Chelated Calcium Magnesium Zinc

Mfd. by Puritan's Pride, Inc.

3 caplets

1,000 mg
(calcium carbonate, gluconate)
✔

400 mg^>UL
(magnesium oxide, gluconate)
✔

Heavy metals: Pass

Also tested for disintegrationⓘ

For adults, take three (3) caplets daily, preferably with a meal.

Large coated caplet

3 caplets

$0.15

[$0.04]

$4.99/100 coated caplets

Zinc 25 mg

No artificial color, flavor or sweetener, no preservatives, no sugar, no milk, no lactose, no soy, no gluten, no wheat, no yeast, no fish. Sodium free.

3 caplets

Total Carbohydrate <1 g, Calcium (as Calcium Carbonate and Calcium Gluconate) 1,000 mg, Magnesium (as Magnesium Oxide and Magnesium Gluconate) 400 mg, Zinc (as Zinc Oxide and Zinc Citrate) 25 mg.

Other Ingredients: Vegetable cellulose, more...

APPROVED

Standard Process® Calcium Lactate

Dist. by Standard Process Inc.

6 tablets

250 mg
(calcium lactate)
✔

50 mg
(magnesium citrate)
✔

Heavy metals: Pass

Also tested for disintegrationⓘ

Six tablets per day, or as directed.

Medium circular tablet

6 tablets

$0.56

[$0.56]

$30.60/330 tablets

Gluten-free.

Precaution: Caution: This product is processed in a facility that manufactures other products containing soy, milk, egg, wheat, peanut, tree nuts, fish and shellfish.

6 tablets

Calories 5, Total Carbohydrate 1 g, Calcium 250 mg, Magnesium 50 mg.

Ingredients: Calcium lactate, magnesium citrate, and calcium stearate.

Calcium, Magnesium & Boron:

APPROVED

Top Pick

for calcium, magnesium & boron

Solgar® Calcium Magnesium Plus Boron

Mfd. by Solgar, Inc.

$ Price Check

3 tablets

1,000 mg
(calcium carbonate, gluconate, citrate)
✔

400 mg^>UL
(magnesium oxide, citrate, gluconate)
✔

3,000 mcg
(boron citrate)
✔

Heavy metals: Pass

Also tested for disintegrationⓘ

As a dietary supplement for adults, take three (3) tablets daily, preferably with a meal, or as directed by a healthcare practitioner.

Medium/large tablet

3 tablets

$0.22

[$0.05]

$17.99/250 tablets

Kosher. Non-GMO. Suitable For Vegans. Free Of: Gluten, Wheat, Dairy, Soy, Yeast, Sugar, Artificial Flavor, Sweetener and Preservatives.

3 tablets

Calcium (as calcium carbonate, calcium gluconate, calcium citrate) 1,000 mg, Magnesium (as magnesium oxide, magnesium citrate, magnesium gluconate) 400 mg, Sodium 10 mg, Boron (as boron citrate) 3 mg.

Other Ingredients: Microcrystalline cellulose, vegetable cellulose, citric acid, more...

Calcium, Magnesium & Vitamin D:

APPROVED

Caltrate® Bone Health Advanced

Dist. by Pfizer

1 tablet

600 mg
(calcium carbonate)
✔

40 mg
(magnesium oxide)
✔

800 IU (20 mcg)
(D3)
✔

Heavy metals: Pass

Take one (1) chewable tablet up to two times daily with or without food or as directed by your physician.

Medium/large circular chewable tablet

1 tablet

$0.10

[$0.04]

$14.97/155 chewable tablets

None.

1 tablet

Calories 0, Total Carbohydrates <1 g, Total Sugars [Includes 0 g Added Sugars] 0 g, Sugar Alcohol <1 g, Vitamin D3 20 mcg (800 IU), Calcium 600 mg, Magnesium 40 mg, Zinc 7.5 mg, Copper 0.25 mg, Manganese 1.8 mg, more...

APPROVED

Top Pick

for calcium, magnesium & vitamin D

Puritan's Pride® Calcium Magnesium Vitamin D3

Dist. by Puritan's Pride, Inc.

3 caplets

1,000 mg
(calcium from oyster shell)
✔

500 mg^>UL
(magnesium oxide)
✔

400 IU (10 mcg)
(D3)
✔

Heavy metals: Pass

Also tested for disintegrationⓘ

For adults, take three (3) caplets daily, preferably with meals.

Large coated caplet

3 caplets

$0.20

[$0.05]

$7.99/120 coated caplets

No artificial flavor, no artificial sweetener, no preservatives, no sugar, no milk, no lactose, no soy, no gluten, no wheat, no yeast. Sodium free.

3 caplets

Vitamin D (as D3 Cholecalciferol) 10 mcg (400 IU), Calcium (as Oyster Shell) 1,000 mg, Magnesium (as Magnesium Oxide) 500 mg.

Other Ingredients: Vegetable cellulose, contains <2% of: natural palm leaf glaze, polydextrose, titanium dioxide color, triacetin, more...

APPROVED

Rainbow Light® Food-Based Calcium™ With Magnesium & Vitamin D3

Dist. by Rainbow Light Nutritional Systems®

$ Price Check

1 tablet

500 mg
(calcium carbonate, amino acid chelate, citrate-malate)
✔

250 mgⓘ
(magnesium oxide, aspartate)
✔

500 IU (12.5 mcg)
(D3)
✔

Heavy metals: Pass

Also tested for disintegrationⓘ

For pure and potent protection, take one tablet per day, with or between meals. May take 2 per day in divided doses for advanced usage.

Large tablet

1 tablet

$0.10

[$0.05]

$17.99/180 tablets

Betaine HCl 20 mg, stinging nettle [tops] 20 mg, horsetail [whole herb] 20 mg, organic spirulina 20 mg

Free of gluten, wheat, milk/dairy, nuts, soy, eggs, fish, shellfish, yeast, sugar, artificial additives.

1 tablet

Calcium (as Carbonate, Amino Acid Chelate, Citrate-Malate) 500 mg, Magnesium (as Oxide, Aspartate) 250 mg, Vitamin D (as D3 Cholecalciferol) 500 IU, Betaine HCl 20 mg, Stinging Nettle [tops] 20 mg, Horsetail [whole herb] 20 mg, Organic Spirulina 20 mg, more...

Children's Products Containing Calcium, Magnesium & Vitamin D:

APPROVED

Bluebonnet Rainforest AnimalZ® Calcium Magnesium & Vitamin D3 - Vanilla Frosting Flavor

Dist. by Bluebonnet Nutrition Corporation

$ Price Check

2 chewables

250 mg
(calcium carbonate, citrate, malate)
✔

50 mg
(magnesium oxide, bisglycinate chelate)
✔

200 IU (5 mcg)
(D3)
✔

Heavy metals: Pass

As a dietary supplement for children three years of age or older, take two animal-shaped chewables once daily or as directed by a healthcare practitioner.

Medium/large animal-shaped chewable tablet

2 chewables

$0.23

[$0.23]

$10.24/90 chewables

Super fruit and veggie blend 30 mg

Kosher. Gluten free. Free of milk, egg, fish, crustacean shellfish, tree nuts, peanuts, peanuts, wheat and soybeans. Also free of yeast, gluten, barley and sodium.

2 chewables

Calories 6, Total Carbohydrate 1.5 g, Sugars [Includes 1.5 g added sugars] 1.5 g, Vitamin D3 (as 200 IU cholecalciferol) 5 mcg, Calcium (as carbonate, citrate, malate) 250 mg, Magnesium (as oxide, bisglycinate chelate) 50 mg, more...

APPROVED

Top Pick

for children's calcium, vitamin D & magnesium

Pioneer® Children's Cal Mag & D - Cocoa

Mfd. by Healthway Corp.

$ Price Check

2 tablets

250 mg
(calcium carbonate, citrate)
✔

85 mg
(magnesium oxide, citrate)
✔

200 IU (5 mcg)
(D3)
✔

Heavy metals: Pass

Children ages 4-8: Two chewables once daily. Children ages 9-13: Two chewables two times daily.

Medium/large circular chewable tablet

2 tablets

$0.15

[$0.15]

$9.18/120 chewable tablets

Trace mineral complex 10 mg

Gluten free. Product contains no added artificial colors or flavors. Formulated to be free of dairy.

2 chewables

Calories 5, Total Carbohydrate 2 g, Sugar Alcohol 1 g, Vitamin D-3 (from cholecalciferol) 200 IU, Calcium (3:1 from carbonate: citrate) 250 mg, Magnesium (2:1 from oxide: citrate) 85 mg, Trace Mineral Complex (from sea vegetation: Lithothamnion spp.) 10 mg, more...

Calcium, Magnesium, Boron & Vitamin D:

NOT APPROVED

Natural Vitality® Natural Calm Plus Calcium - Raspberry-Lemon Flavor

Dist. by Natural Vitality

1 teaspoon [2.5 g]

70 mg
(calcium gluconate)
✔

106.7 mg
(magnesium citrate)
✔

88.3 mcg
(boron citrate)
Found 198.5 mcg boron per serving (224.7% of listed amount)

35 IU (0.88 mcg)
(D3)
Found only 22.1 IU vitamin D per serving (63.1% of listed amount)

Heavy metals: Pass

Take 1 - 1 1/2 rounded teaspoons twice per day at any time, at least 5 hours apart.

Powder in container

1 teaspoon

$0.17

[$0.62]

$15.57/8 oz [226 g] container (approx. 90 servings)

Vitamin C 88.3 mg, potassium (elemental from potassium citrate) 35 mg

Vegetarian. Gluten-Free. Non GMO Project Verified seal. Contains no yeast, dairy, egg, gluten, soy, wheat, sugar, starch, preservatives or artificial color or flavor.

1 teaspoon

Vitamin C (as ascorbic acid) 88.3 mg, Vitamin D3 (as cholecalciferol) 35 IU, Calcium (elemental from calcium gluconate) 70 mg, Magnesium (elemental from magnesium citrate) 106.7 mg, Potassium (elemental from potassium citrate) 35 mg, Boron (elemental from boron citrate) 88.3 mcg.

Ingredients: Calcium gluconate, more...

APPROVED

Vitalite Now! Calcium & Magnesium Plus

Dist. by Vitalite Now!

4 capsules

1,000 mg
(calcium carbonate, dicalcium phosphate, citrate, amino acid chelate, hydroxyapatite, gluconate, lactate, orotate, succinate and alpha ketoglutarate)
✔

500 mg^>UL
(magnesium oxide)
✔

4,000 mcg
(boron amino acid chelate)
✔

400 IU (10 mcg)
(D3)
✔

Heavy metals: Pass

4 capsules daily preferably with meals or as directed by a healthcare professional.

Large capsule

4 capsules

$0.47

[$0.12]

$27.90/240 capsules

Phosphorus 77 mg

Precaution: This product is manufactured and packaged in a facility which may also process milk, soy, wheat, egg, peanuts, tree nuts, fish and crustacean shellfish.

4 capsules

Vitamin D-3 (cholecalciferol) 400 IU, Calcium (from carbonate, dicalcium phosphate, citrate, amino acid chelate, hydroxyapatite, gluconate, lactate, orotate, succinate and alpha ketoglutarate) 1,000 mg, Phosphorus (dicalcium phosphate) 77 mg, Magnesium (from oxide) 500 mg, Boron (from amino acid chelate) 4 mg.

Other Ingredients: Gelatin (bovine), vegetable magnesium stearate and rice flour.

Calcium, Magnesium, Vitamin D & Vitamin K:

APPROVED

New Chapter® Bone Strength Take Care™

Dist. by New Chapter, Inc.

$ Price Check

3 tablets

770 mg
(calcium from algae Lithothamnion calcareum & corallioides)
✔

58 mg
(magnesium from algae Lithothamnion calcareum & corallioides)
✔

1,000 IU (25 mcg)
(D3)
✔

35 mcg
(K1)
45 mcg
(MK-7 K2)
80 mcg
(total vitamin K)
✔

Heavy metals: Pass

Also tested for disintegrationⓘ

Three tablets daily with food.

Large slim tablet

3 tablets

$0.96

[$0.31]

$38.37/120 slim tablets

Strontium 5 mg, silica 2 mg, vanadium 13 mcg

Kosher. Non GMO Project Verified seal. Gluten free; 100% vegetarian; no artificial flavors or colors.

Precaution: Contains: Fermented soy.

3 tablets

Vitamin D3 (as cholecalciferol from ferment media) 1,000 IU, Vitamin K1 (as phylloquinone from ferment media) 35 mcg, Vitamin K2 (as menaquinone-7 from natto) 45 mcg, Calcium (from algae Lithothamnion calcareum & corallioides) 770 mg, Magnesium (from algae Lithothamnion calcareum & corallioides) 58 mg, Strontium (from algae Lithothamnion calcareum & corallioides) 5 mg, Silica (from algae Lithothamnion calcareum & corallioides) 2 mg, Vanadium (from algae Lithothamnion calcareum & corallioides) 13 mcg, more...

NOT APPROVED

Thorne® Basic Bone Nutrients

Mfd. by Thorne Research, Inc.

1 capsule

200 mg
(DimaCal® DiCalcium Malate)
✔

50 mg
(Albion® DiMagnesium Malate)
✔

500 IU (12.5 mcg)
(D3)
Found only 348.5 IU vitamin D per serving (69.7% of listed amount)

45 mcg
(MK-7 K2)
Found only 1 mcg vitamin K per serving (2.2% of listed amount)

Heavy metals: Pass

Take 1 capsule one to four times daily or as recommended by a health-care practitioner.

Large capsule

1 capsule

$0.32

[$0.40]

$38.00/120 capsules

Gluten Free.

1 capsule

Vitamin D (as Vitamin D3) (500 IU) 12.5 mcg, Vitamin K (as K2 (MK-7)) 45 mcg, Calcium (as DimaCal® DiCalcium Malate) 200 mg, Magnesium (as Albion® DiMagnesium Malate) 50 mg.

Other Ingredients: Hypromellose (derived from cellulose) capsule, calcium laurate.

Calcium, Magnesium, Boron, Vitamin D & Vitamin K:

APPROVED

GNC Calcimate Complete™

Dist. by General Nutrition Corporation

4 caplets

800 mg
(calcium citrate malate)
✔

100 mg
(magnesium oxide)
✔

1,000 mcg
(boron hydrolyzed protein chelate)
✔

2,000 IU (50 mcg)
(D3)
✔

50 mcg
(K2)
✔

Heavy metals: Pass

Also tested for disintegrationⓘ

As a dietary supplement, take two caplets at breakfast and two caplets at dinner for a total of four caplets daily.

Large caplet

4 caplets

$0.25

[$0.08]

$14.99/240 caplets

Zinc 7.5 mg, copper 1 mg, manganese 1 mg, MBP® 40 mg

No artificial colors, no artificial flavors, no wheat, gluten free, yeast free.

Precaution: Contains: Milk and soybeans.

4 caplets

Vitamin D (as Cholecalciferol D-3) 2,000 IU, Vitamin K-2 (as Menaquinone) 50 mcg, Calcium (as Calcium Citrate Malate) 800 mg, Magnesium (as Magnesium Oxide) 100 mg, Zinc (as Zinc Oxide) 7.5 mg, Copper (as Copper Glycinate) 1 mg, Manganese (as Manganese Gluconate) 1 mg, MBP® 40 mg, Boron (as Hydrolyzed Protein Chelate) 1 mg.

Other Ingredients: Cellulose, titanium dioxide (natural mineral whitener), vegetable acetoglycerides.

APPROVED

Top Pick

for calcium, magnesium, boron, vitamin D & vitamin K

Jarrow Formulas® Bone-Up®

Dist. by Jarrow Formulas®

$ Price Check

6 capsules

1,000 mg
(StimuCal™ microcrystalline hydroxyapatite)
✔

500 mg^>UL
(magnesium oxide)
✔

3,000 mcg
(boron citrate)
✔

1,000 IU (25 mcg)
(D3)
✔

45 mcg
(MK-7 K2)
✔

Heavy metals: Pass

Take 2 capsules 3 times per day (for a total of 6) with meals to facilitate maximum absorption, or as directed by your qualified healthcare professional.

Large capsule

6 capsules

$0.51

[$0.13]

$20.37/240 capsules

Vitamin C 200 mg, zinc 10 mg, copper 1 mg, manganese 1 mg, potassium 99 mg

No wheat, gluten, egg, fish/shellfish, or peanuts/tree nuts.

Precaution: Contains: Soy (in trace amounts).

6 capsules

Vitamin C (as Calcium Ascorbate) 200 mg, Vitamin D3 (Cholecalciferol) 25 mcg (1,000 IU), Vitamin K2 (as Natural MK-7 [Menaquinone-7]) 45 mcg, Calcium (Elemental) (from StimuCal™ Microcrystalline Hydroxyapatite) 1,000 mg, Magnesium (as Magnesium Oxide) 500 mg, Zinc (L-OptiZinc®) (as Zinc L-Methionine Sulfate) 10 mg, Copper (as Copper Gluconate) 1 mg, more...

Unless otherwise noted, information about the products listed above is based on the samples purchased by ConsumerLab.com (CL) for this Product Review. Manufacturers may change ingredients and label information at any time, so be sure to check labels carefully when evaluating the products you use or buy. If a product's ingredients differ from what is listed above, it may not necessarily be of the same quality as what was tested.

The information contained in this report is based on the compilation and review of information from product labeling and analytic testing. CL applies what it believes to be the most appropriate testing methods and standards. The information in this report does not reflect the opinion or recommendation of CL, its officers or employees. CL cannot assure the accuracy of information.

Copyright ConsumerLab.com, LLC, 2021 All rights reserved. Not to be reproduced, excerpted, or cited in any fashion without the express written permission of ConsumerLab.com LLC

ConsumerTips™:

What to Consider When Buying:
The most common and generally least expensive form of calcium is calcium carbonate. Oyster shell and coral calcium contain calcium carbonate, although coral calcium products may contain other inherent minerals. According to some but not all studies, calcium citrate or citrate malate may be better absorbed and/or more effective at raising levels of available (ionized) calcium in the body than calcium carbonate which, unlike the other forms, requires stomach acid to become soluble (which is also why it must be taken with food, as this stimulates acid production) (Yang, Curr Gastro Rep 2012; Heaney, J Am Col Nutr 2001). This difference may be particularly important for people with low levels of stomach acid (which can occur with increasing age and with some drugs, such as proton pump inhibitors such as omeprazole [Prilosec] and H2 blockers such as ranitidine [Zantac]). However, one downside with these forms of calcium, and some other types such as calcium lactate and calcium gluconate, is that the amount of calcium in them is small relative to the rest of the molecule, meaning that more pills or larger pills need to be taken than with calcium carbonate. They also tend to be more expensive.

Another form of calcium, calcium hydroxyapatite, is derived from cow bone. It contains other minerals (magnesium, phosphorus, potassium etc.) and is often sold as microcrystalline hydroxyapatite (MCH) or ossein hydroxyapatite complex (OHC). It also naturally includes bone proteins, like collagen. It appears to be roughly equivalent to calcium citrate and calcium carbonate in slowing bone turnover. It seems to do this without causing as large a spike in blood levels of calcium, but it is not necessarily a safer form of calcium as it causes higher concentrations of calcium-phosphate, which is associated with a higher risk of cardiovascular disease (Bristow, Br J Nutr 2014). Calcium hydroxyapatite is less likely to cause constipation than calcium carbonate.

Calcium is sometimes sold as part of a "food-based" or "plant-based" formula, such as AlgaeCal (AlgaeCal Inc.), which is derived from algae (algas calcareas). The calcium in AlgaeCal, according to its website, consists of a complex of calcium hydroxide, calcium chloride, calcium sulfate and calcium carbonate. AlgaeCal Basic provides 750 mg of elemental calcium per recommended daily serving of 3 capsules, as well as magnesium and added vitamin D3. AlgaeCal Plus provides 720 mg of elemental calcium per recommended daily serving of 4 capsules, plus added magnesium, vitamin D3, boron, vitamin C and vitamin K-2. Two company-funded clinical studies found that various formulations of AlgaeCal (providing between 720 mg and 756 mg of calcium daily) taken for six months to one year increased bone mineral density by 1.3% to 4.1%, in healthy men and women — although the studies involved some increased physical activity, no placebo controls, and both the participants and researchers knew which formulation they received. No adverse side-effects were reported (Michalek, Nutr J 2011; Kaats, Int J Med Sci 2011). One laboratory study found that, compared to calcium carbonate and calcium citrate, AlgaeCal significantly increased measures of growth in cultured bone cells (Adluri, Mol Cell Biochem 2010). There do not appear to be any clinical studies comparing the effects of AlgaeCal with other forms of calcium in people. ConsumerLab.com tests of AlgaeCal Plus in 2011 found it contained an elevated level of lead -- 5.3 mcg in a daily serving of 4 capsules (providing 720 mg of calcium), although this has decreased to 1.4 mcg, as noted above in this current Review which also found only 86.7% of the listed amount of magnesium.

The type of calcium, amount of calcium, and inclusion of other ingredients, such as vitamin D or vitamin K, should be considered when comparing the costs of products.

Product labels should indicate the amount of actual "calcium" (or "elemental calcium") per dosage unit. This is important because calcium actually makes up less than half of the weight of calcium compounds. For example, only 40% of the weight of calcium carbonate is calcium, as is only 9% of the weight of calcium gluconate and 21% of the weight of calcium citrate. The Supplement Facts panel on a properly labeled product with 500 mg of elemental calcium from 1,250 mg of calcium carbonate, for example, would correctly read "Calcium (as calcium carbonate) 500 mg" or "Calcium (from calcium carbonate) 500 mg". However, if the Supplement Facts panel reads "Calcium carbonate 500 mg," there is only 200 mg of elemental calcium.

What to Consider When Using:

In a 2010 report, the Institute of Medicine (IOM) concluded that most individuals currently receive enough calcium for bone health, with the exception of girls ages 9 to 18, who often do not take in enough calcium. In contrast, postmenopausal women taking supplements may be getting too much calcium, thereby increasing their risk for kidney stones.

The recommended daily intake of calcium as determined by the IOM varies by age. For women ages 19 to 50, and men up to age 70, 1,000 mg/day is recommended. For women ages 51 and older and men 71 and older it is 1,200 mg/day for men and 1,200 mg/day for women. For younger individuals the recommended amounts are 1,300 mg/day (ages 9 through 18), 1,000 mg/day (ages 4 to 8), and 700 mg/day (ages 1 to 3). While the recommended intake is not higher during pregnancy or breast-feeding (because women's bodies are better able to absorb and maintain calcium during these times), it is particularly important for these women to have sufficient calcium intake because it can significantly affect the bone density of their children.

How much calcium do you already get from food? Bear in mind that the recommended amounts above are for total daily calcium intake from all sources. Consequently, the calcium which you consume from food each day should be factored in when determining how much calcium, if any, is needed from supplements. For example, a cup of milk or yogurt provides 300 to 400 mg of calcium, and a cup of cottage cheese or ice cream offers about 200 mg. Other foods which provide calcium include soybeans (about 250 mg per cup — cooked), white beans (190 mg per cup), and tofu (160 mg per ¼ firm block). Spinach is also high in calcium (about 100 to 200 mg per cup — cooked), however, most of it is not absorbed due oxalate compounds in spinach which bind the calcium (Brogren, Asia Pac J Clin Nutr 2003; Heaney, Am J Clin Nutr 1988). You also get smaller amounts of calcium from a wide range of fruits, vegetables, nuts, and meats; even a slice of bread provides about 20 mg of calcium (USDA National Nutrient Database).

Also, keep in mind that using over-the-counter heartburn relief products that contain calcium, like Tums, can contribute a significant amount of calcium to your daily intake. Even using such products as directed can add up to more than 1,000 mg of calcium per day (see Cautions and Concerns for more about the risks of getting too much calcium from supplements). For example, Tums Regular provides 200 mg of elemental calcium per tablet. The directions for use recommend taking 2 to 4 tablets as heartburn symptoms occur, not exceeding 15 tablets in 24 hours. Taking four tablets would provide 800 mg of elemental calcium, and taking the maximum dose would provide 3,000 mg of elemental calcium! Other versions of Tums (Smoothies and Ultra) contain even more calcium (300 mg and 400 mg per tablet, respectively).

Dosage for specific uses:
The following amounts of calcium appear to be useful in certain situations. Keep in mind, however, that it may be safer to obtain these amounts (in whole or part) from foods.

For slowing bone loss, calcium (generally as calcium citrate) at a dose ranging from of 1,000 mg to 1,200 mg daily (combined with 400 IU to 800 IU daily of vitamin D) has been found effective in multiple studies.

For building bone in young girls (ages 9 to 13), a study found benefit with a supplement providing, on a daily basis, 800 mg of calcium (from calcium citrate and calcium carbonate), 400 IU of vitamin D3, and 400 mg of magnesium (from magnesium citrate) when taken regularly for six months (Greene, Osteoporosis Int 2011). The supplement (Active Calcium Chewable, USANA Health Sciences, Inc. -- not tested as part of this Review) was taken as four chewable tablets, two with breakfast and two with dinner.

To help reduce PMS symptoms 1,200 mg of calcium per day from calcium carbonate has been found to be effective in one substantial study.

How to take:

When taking calcium supplements, it is generally suggested to divide the doses during the day so that no more than 500 mg are taken at a time because it is thought that the body cannot absorb more than this amount at one time. In addition, calcium levels are regulated in the body by parathyroid hormone (PTH), so getting too much calcium at a time may simply mean excreting more of it. It may, therefore, be better to take doses more in-line with amounts one would get from eating a calcium-rich meal, which would also suggest a dose lower than 500 mg. It is generally best to take calcium, particularly calcium carbonate, with a meal, although calcium citrate may be taken without food.

Magnesium and calcium are "macrominerals:" meaning that their RDAs are relatively high compared to "microminerals," such as iron and zinc, for which only a few milligrams or microgram amounts are needed. Both magnesium and calcium supplements can interfere with the absorption of "microminerals." As a result, it is probably best to take microminerals at a different time of day from a magnesium or calcium supplement. This is particularly important if you are prone to iron-deficiency, so take calcium (particularly if at a dose of 300 mg or more) at least 2 hours apart from an iron supplement or iron-containing meal (see the ConsumerTips™ section of the Iron Review for more information).

It is important to note that calcium can only be beneficial when you have an adequate level of vitamin D. Many of the products in this review include vitamin D for this reason. To find additional vitamin D products, including vitamin D-only supplements, see our Review of Vitamin D Supplements.

Some calcium supplements contain the trace mineral boron, typically in amounts ranging from less than 1 mg up to about 6 mg per daily serving. Some, but not all evidence suggests that boron may reduce calcium loss in the urine, especially when magnesium intake is low (Neilson, FASEB J 1987). Although some preliminary research suggests boron supplementation in doses of 3 mg to 10 mg per day may be helpful for osteoarthritis and osteoporosis, one small trial found no increase in spine or thigh bone mineral density in postmenopausal women who took 3 mg of boron daily for one year compared to placebo (Biquet, Osteoporos Int 1996). Americans typically get an average of about 1 mg to 1.25 mg of boron daily from foods such as leafy vegetables, raisins, prunes, non-citrus fruits like apples, and some grains (Rainey, J Am Diet Assoc 1999). There is no established daily requirement for boron, but there is an upper tolerable intake level of 20 mg for per day for adults. Be aware that even at doses of 3 mg to 10 mg daily, boron may increase estrogen levels in both women and men (Neilson, FASEB J 1987; Naghii, Biol Trace Elem Res 1997). This may be of particular concern for women on hormonal therapy or those with a history of estrogen-sensitive cancer.

Concerns and Cautions:

Some people experience gastrointestinal side effects such as gas, bloating or constipation when taking calcium supplements. Calcium carbonate may cause more of these side effects than calcium citrate (Institute of Medicine, Dietary Reference Intakes for Calcium and Vitamin D 2010). Taking your calcium supplement with meals or in divided doses throughout the day may help to reduce these effects.

Drug Interactions:
A study that analyzed dietary supplement and medication use among 62 older adults (age 60 or older) in Texas found that 50% of those who reported using dietary supplements (24 out of 48) were at-risk for a potential supplement-medication interaction and that calcium was the dietary supplement with the most potential drug interactions (de Leon, J Nutr Gerontol Geriatr 2018).

Calcium supplements can impair the absorption of thyroid hormone as well as antibiotics in the fluoroquinolone (e.g., Cipro) and tetracycline families. Research shows negative effects of taking calcium within 2 hours after levothyroxine (Synthroid) but indicates that this can be avoided by postponing calcium 6 to 8 hours after taking levothyroxine (Morini, Endocrine 2018).

Individuals taking prescription bisphosphonate medications such as alendronate (Fosamax) to treat osteoporosis are often advised to take calcium/vitamin D supplements if they do not get adequate amounts from their diet; however, as calcium supplements and antacids containing calcium can interfere with the absorption of these medications, wait at least 30 minutes after taking alendronate before taking calcium (Fosamax Prescribing Information 2012).

Taking calcium supplements and antacids containing calcium, especially in large doses, may increase the risk of hypercalcemia associated with the use of thiazide diuretic drugs used to treat high blood pressure and fluid retention, such as hydrochlorothiazide (Esidrix, Ezide, Microzide). For example, a 67-year old woman taking hydrochlorothiazide developed milk-alkali syndrome (high blood levels of calcium and metabolic acidosis) after consuming 10 to 15 Tums antacid tablets daily for several weeks (Hakim, Can Med Assoc J 1979).

Be aware that a high dose of TUMS can temporarily elevate blood levels of calcium. Mild hypercalcemia was reported in a 61-year-old man with type II diabetes after he consumed six chewable TUMS tablets (200 mg of calcium in each) in a single evening to treat an episode of heartburn. Elevated blood levels of calcium (11.1 mg/dL) were discovered through blood tests the next day as part of a routine exam, although he did not experience any symptoms. He was advised to avoid TUMS, and five days later his blood levels of calcium decreased to within normal range (Cimpeanu, SAGE Open Med Case Rep 2020).

Avoid taking calcium citrate along with medications that contain aluminum (such as aluminum hydroxide in the antacid Maalox), as citrate can increase the absorption of aluminum (Coburn, Am J Kidney Dis 1991). In people with normal kidney function, calcium citrate does not appear to increase the aluminum retention from food (Sakhaee, Bone Miner 1993); however, people with kidney disease might want to avoid calcium citrate due to their reduced ability to eliminate aluminum from the body.

Risks of Getting Too Much Calcium:
Officially, the tolerable upper intake level (UL) for calcium (above which there is an increased risk of adverse effects, such as kidney stones) is 2,500 mg per day for most people 1 year and older, rising to 3,000 mg for those ages 8 to 18 and falling to 2,000 mg for those over 50 (IOM, 2011). This includes calcium from foods as well as supplements. However, getting too much calcium from foods is rare; excess intakes are more likely to be caused by the use of calcium supplements, so it may be best to get most of your calcium from foods, reducing amounts from supplements. Keep in mind that getting calcium from calcium-fortified foods, such as orange juice, soy milk, almond milk and even calcium-fortified milk, is considered the same as taking a calcium supplement since much of the calcium they contain is added. Despite the ULs noted above, even lower daily intakes of calcium, typically from supplements, have been associated with risks for adults.

Prostate Cancer Risk
Some, but not all observational studies have found an association between high total calcium intakes and an increased prostate cancer risk. In general, these findings indicate that a total calcium intake of more than 1,500 mg of calcium per day (from both food and supplements) may increase the risk of prostate cancer, especially advanced prostate cancer, compared to a total daily intake of between 500 and 1,000 mg per day (NIH ODS 2013). However, one review of calcium intake among U.S. veterans suggests that low calcium intake from food may also increase the risk of prostate cancer (Williams, Prev Chronic Dis 2012). The researchers proposed that both too little and too much calcium from food might increase the risk of prostate cancer, whereas adequate intakes may be protective. Adequate intake (AI) for men age 51- 70 is 1,000 mg/day and for men age 71 or older, 1,200 mg/day (Bailey, J Nutr 2010) — this amount can easily be obtained from just a few servings of dairy or certain vegetables. There is little research on the effect of calcium specifically from supplements on prostate cancer risk, although one randomized, placebo-controlled clinical study found that 3 grams of calcium carbonate (providing 1,200 mg of calcium) taken daily for 4 years did not increase the risk of prostate cancer (average age of the men in this study was 62) (Baron, Cancer Epidemiol Biomarkers Prev 2005).

Kidney Stone Risk
Postmenopausal women taking a daily calcium (1,000 mg) and vitamin D (400 IU) supplement showed a 17% increase in kidney stones compared to women who did not receive the supplement (Wallace, Am J Clin Nutr 2011). The increased risk, however, is small, as only 0.35% of the women taking the calcium/vitamin D supplement reported kidney stones, compared to 0.30% of the women in the control group. A similar (17% to 20%) increase in kidney stones has been reported in studies with calcium supplementation alone, suggesting that calcium, rather than vitamin D, is the causative factor. The increased risk of kidney stones in women has been observed with calcium from supplements but not with calcium from dietary sources. However, there is some evidence that very high-dose vitamin D (10,000 IU daily) can markedly increase levels of calcium in the urine (hypercalciuria) from calcium supplementation, which, in turn, can increase the risk of kidney stones.

Use of calcium supplements has also been shown to significantly increase the rate of growth of kidney stones in postmenopausal women. A review of CT scans of such women with a history of kidney stones showed that among those taking calcium supplements (averaging 439 mg per day), stones grew at an average rate of 7.8 millimeters per month, compared 4.49 millimeters among those not taking calcium. Vitamin D supplementation showed no added risk and, potentially, a protective effect (stones grew at only 3.3 millimeters per month). (Loftus, J Am Soc Nephrol Abstract Supplement p. 584A 2015)

A study in which postmenopausal women with low vitamin D blood levels (below 20 ng/mL) were given varying amounts of calcium (calcium citrate) and vitamin D3 supplementation, showed that the risk of developing abnormally high calcium levels in the urine (a risk factor for kidney stones) was not associated with the amount of vitamin D supplementation, but with calcium supplementation. The women were given only enough calcium from supplements to get their total daily intake (including that from food) up to about 1,200 mg, with 70% of the women requiring 600 to 800 mg of supplemental calcium per day. The study showed that a woman starting with a 24-hour urine calcium level higher than 132 mg had a 15 times greater risk of developing an abnormally high urine calcium level (300 mg or higher) when given calcium supplementation than a woman starting a urine calcium level of 132 mg or less. The researchers cautioned that even supplementing with 600 mg of calcium per day may be too much for some women who might otherwise seem to need it based on their estimated intake of calcium from food. They advise checking blood and urine calcium levels before starting supplementation, and checking again after 3 months, noting that 5% to 8% of men and women have idiopathic hypercalciuria (too much calcium in the urine for unknown reasons), which is a risk factor for kidney stones (Gallagher Menopause 2014).

Heart Attack and Stroke Risk
Studies have shown an increased risk of heart attack and/or stroke with taking more than 1,000 mg of calcium from a supplement daily. The risk may be greater among those already getting substantial calcium from their diet and lower when supplementing with vitamin D.

An analysis of results pooled from a number of clinical trials showed a 30% increase in the risk of heart attack among adults taking calcium supplements compared to those who did not. A small, non-significant increase in the risk of stroke and death was also noted. However, calcium intake from foods (such as dairy) alone, without supplementation, was not associated with increased cardiovascular risk, consistent with findings from other studies. The risk of heart attack with calcium supplementation tended to be greater in those already getting more than 805 mg of calcium from their diet (excluding supplements), and was not related to the type of calcium supplement. The study did not evaluate the effects of calcium given with vitamin D (Bolland, British Medical Journal 2010). A subsequent study by the same researchers similarly concluded that calcium supplements modestly increase the risk of cardiovascular events, especially myocardial infarction, and it found that the use of vitamin D supplements did not affect this risk (Bolland, British Medical Journal 2011).

However, a large study in Korea among adults who had osteoporosis but no history of heart attack, stroke, atrial fibrillation, or heart failure found that, compared to no use of calcium supplements, the use of calcium supplements for at least three months (average daily dose and duration 538 mg for 22 months) without vitamin D supplementation was associated with a 54% increased risk of major adverse cardiovascular events (heart attack, stroke or cardiovascular death) and an 89% increased risk of non-fatal heart attack, even after adjusting for other risk factors such as high blood pressure, cholesterol levels and activity levels. However, there was no increased risk of heart attack or other major cardiovascular events associated with calcium supplementation with vitamin D. Although the study did not measure blood levels of calcium or vitamin D or assess calcium intake from foods, the average estimated dietary intake of calcium among Korean adults is just 490 mg per day, far below recommended daily intake in the U.S. (Kim, Eur Heart J Cardiovasc Pharmacother 2021).

A study of men and women ages 40 to 89 found that calcium supplementation at high daily doses (over 1,000 mg per day) is associated with a doubling in the risk of ischemic stroke (i.e., stroke due to blockage) — and the risk was higher in men (3X risk) compared to women (1.7X risk). No significant increase in risk was observed when calcium supplements were used either at low-doses or in association with vitamin D. The study focused on cases of nonfatal stroke and did not evaluate the risk of fatal stroke (de Abajo, J Am Heart Ass 2017).

A large study of men and women aged 35 to 64 found an increased risk of heart attack associated with calcium supplementation, although not with intake of calcium from foods (Li, Heart 2012). Compared to those who did not use any supplements, those who used supplements that provided calcium and other vitamins and minerals were 86% more likely to have had a heart attack during the study period (which averaged 11 years), and the risk increase was greater (139%) among those who reported using only calcium supplements. Unfortunately, the dosage of calcium was not recorded.

Looking specifically at the risk of death from cardiovascular disease (CVD) when supplementing with calcium, a large, 12-year study found that intakes of over 1,000 mg of calcium from multivitamins or individual calcium supplements were associated with a 20% increase in death from CVD among men (Xiao, JAMA Intern Med 2013). This association did not exist for women, or with calcium intake from foods. However, the risk of death from CVD decreased with increasing total calcium intakes (from all sources combined) up to approximately 1,200 mg per day (which is the RDA for women and all older adults) — indicating the importance of maintaining adequate calcium intake, but limiting intake from supplements. A 19-year study in Sweden, however, suggests a higher risk of death for women with high calcium intake, particularly from supplements: Compared to women with moderate calcium intakes (600 mg to 1,000 mg per day), those with intakes of 1,400 mg or more daily from their diet were 40% more likely to die during the period of the study; and if they were also taking a 500 mg calcium supplement daily, the risk of death was 157% higher than among the women with moderate calcium intake (Michaelsson, BMJ 2013).

A 2-year study in which women in China with high cholesterol levels were given a daily calcium supplement showed a negative effect in those who were post-menopausal (ages 50 to 60 years), although not in those who were pre-menopausal (ages 30 to 40 years). Post-menopausal women given the calcium supplement experienced significant increases in total cholesterol levels (up by about 50 mg/dL) and in the thickness of the lining of the carotid artery, compared to women given placebo (Li, Am J Clin Nutr 2013). These changes are associated with increased risk of heart disease. It is important to note, however, that the study involved taking a single daily tablet containing 800 mg of calcium (from calcium carbonate) with supper. It is generally felt that calcium supplementation should not exceed 500 mg per dose.

A study of 1,567 men and women in the U.S. without coronary artery calcification (i.e., atherosclerosis) found that, after 10 years, those who had reported higher total daily intakes of calcium (which was only recorded at the start of the study) had a lower risk of developing calcification during the study. However, the use of calcium supplements was associated with a 22% increase in the risk of calcification. The lowest risk of calcification was among non-users of calcium supplements with the highest total daily intake of calcium (Anderson, J Am Heart Assoc 2016). Calcium supplementation also increases the risk of progression of calcification among people with coronary artery disease, as determined in an analysis of data from nine previously conducted clinical trials among 5,147 people (average age 58) that found the odds of calcification progression was 1.15 times higher for those who used calcium supplements compared to those who did not (Bazarbashi, JACC Cardiovasc Imaging 2020).

In adults, little of the additional calcium provided by calcium supplements is incorporated in bone (Warensjo, BMJ 2011). Some researchers speculate that the burst of calcium in the blood following supplementation may "drive the atherogenic process" facilitating the development of calcifications in arteries (Reid, Heart 2012). Calcium from food is absorbed at a slower rate and, typically, in smaller quantities than from supplements. It appears preferable to get calcium from foods and to moderate the amount of calcium you get from supplements.

Dementia Risk
A study which followed 700 women in Sweden between the ages of 70 and 92 for five years found that, among those who reported taking calcium supplements, 14% developed dementia during the study, compared to 8% of women who did not take calcium supplements. Among women with a history of stroke or who had evidence of cerebrovascular disease (white matter brain lesions found by CT scan), those who took calcium supplements were, respectively, seven times, and three times more likely to develop dementia than women without a history of these conditions who did not take supplemental calcium (Kern, Neurology 2016). However, there was no increased risk of dementia among women without a history of stroke or cerebrovascular disease who took calcium supplements (dose of calcium was not stated, but the average recommended daily dose of supplemental calcium in Sweden is 1,000 mg). The findings applied to calcium from supplements only; the researchers did not evaluate calcium intake from foods, but noted that dietary calcium may help to protect against vascular disease.

Age-Related Macular Degeneration (AMD)
As discussed earlier (see What It Does), there is mixed evidence regarding the effects of calcium supplements on the risk of developing AMD.

Other Concerns:
Taking too much calcium during pregnancy might potentially cause abnormalities in the fetus.

High intake of calcium from supplements (particularly 900 mg or more per day) has been associated with an increased risk of early menopause. Calcium from foods has not been associated with this same risk (Purdue-Smith, Am J Clin Nutr 2017).

High doses of calcium or other minerals (magnesium, zinc, and ferrous iron) from supplements may decrease the absorption of carotenoids, such as lycopene, beta-carotene, and astaxanthin, from foods and/or supplements. A small clinical study found that 500 mg of calcium from a calcium carbonate supplement taken with a meal of pasta and pork containing 19 mg of lycopene (from tomato paste) reduced the bioavailability of the lycopene by 83%, compared to the same meal consumed without the supplement (Borel, Br J Nutr 2017). This is likely due to a reaction between carotenoids and the divalent ions of these minerals, making the carotenoids less bioavailable certain forms of iron, (Corte-Real, Food Chem 2016; Biehler, J Nutr 2011). It is best to take carotenoid supplements at a different time of day than a supplement or meal containing large amounts of a mineral (e.g., hundreds of milligrams of calcium or magnesium).

If you take a calcium supplement that includes a large amount (e.g., hundreds of milligrams) of strontium, make sure to tell your healthcare provider, as strontium has a higher atomic weight than calcium and can artificially inflate bone density measurements using dual energy X-ray absorptiometry (DEXA). In cases where 680 mg of strontium (from strontium citrate) was taken daily for more than one year, bone mineral density from DEXA scans was shown to be overestimated by 8% or more, and it can take months to years after discontinuation of strontium to substantially reverse this effect (Mirza, J Nutr Health Food Sci 2016). Also, be aware that there is no research showing strontium citrate to be effective against osteoporosis.

For more information see the government report on calcium at https://ods.od.nih.gov/factsheets/Calcium-Consumer/.

See ConsumerLab.com's separate reviews of Vitamin D and Vitamin K for more information about those nutrients and their role in bone health.

Information on this site is provided for informational purposes only. It is not an endorsement of any product nor is it meant to substitute for the advice provided by physicians or other healthcare professionals. The information contained herein should not be used for diagnosing or treating a health problem or disease. Consumers should inform their healthcare providers of the dietary supplements they take.

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Information on this site is provided for informational purposes only. It is not an endorsement of any product nor is it meant to substitute for the advice provided by physicians or other healthcare professionals. The information contained herein should not be used for diagnosing or treating a health problem or disease. Consumers should inform their healthcare providers of the dietary supplements they take.

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Latest Clinical Research Updates for Calcium Supplements

Reducing Risk of Fractures & Falls With Milk, Cheese and Yogurt?

10/26/2021

Can increasing calcium and protein intake from foods such as milk, cheese and yogurt reduce the risk of fractures and falls in older men and women? See what a new study found in the Bone Health and Fractures section of our Calcium Supplements Review.

Hip Fracture Risk With Vegan Diet

8/10/2021

Does following a vegan diet increase the risk of hip fracture in middle-aged and older women, and does supplementing with calcium and vitamin D help? See what a recent study found in the "What It Does" sections of our Calcium Supplements Review and Vitamin D Supplements Review. Also see our Top Picks among calcium supplements and vitamin D supplements.

Calcium, Vitamin D & Heart Risk

7/21/2021

Does taking vitamin D reduce the cardiovascular risks associated with calcium supplementation? See what a new study found in the Concerns and Cautions section of our Calcium Supplements Review. Also see our Top Picks among calcium supplements.

Caution With TUMS

9/22/2020

A man who took several TUMS to treat heartburn was recently reported to have developed hypercalcemia (too much calcium in the blood), as noted in the Concerns and Cautions section of the Calcium Supplements Review. Learn about getting the right amount of calcium and see our Top Picks among calcium supplements.

Calcium & Artery Calcification

8/25/2020

Is there an increased risk of coronary artery calcification with the use of calcium supplements? Find out what a recent analysis showed in the Heart Attack and Stroke Risk section of the Calcium Supplements Review. Plus, learn how much calcium one needs per day and how much, if any, can come from supplements. Also see our Top Picks for calcium.

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