Zinc Supplements and Lozenges Review
Find the Best Zinc
Supplements and Lozenges. Have a Cold? See CL's Top Picks Among
Zinc Supplements and Lozenges.
Medically reviewed and
edited by Tod Cooperman, M.D. 
Last Updated
: 11/29/2021 | Initially Posted:
10/31/2020
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Table of Contents
Summary
·
What is zinc? Zinc is an essential mineral, one of the
few nutrients for which a mild deficiency is not uncommon (see What It Is). Zinc is naturally found in meats
and other foods (see Getting Zinc — From Food)
·
Who is most likely to be zinc deficient? Mild zinc
deficiency can occur with the use of acid-blocking medications and certain
blood pressure medications. Zinc deficiency can also occur with hypothyroidism.
Vegetarians may require as much as 50% more of the daily requirement for zinc
due to compounds in legumes and grains that can interfere with zinc absorption (See What to Consider When Using).
·
What are the benefits of zinc? Zinc supplements (typically taken in
pill form) can reverse or prevent zinc deficiency (which can otherwise impair
the immune system, cause diarrhea and hair loss, reduce taste, etc.) and help
slow advanced macular degeneration of the retina. Zinc is also taken as a
lozenge (or other orally dissolving formulation) to act locally on the throat
to reduce the duration of a cold. (See What It Does).
·
COVID-19 UPDATE: Zinc deficiency has been associated with more severe
disease and higher mortality rates in people with COVID-19. However, there is
no evidence that supplementing with zinc helps prevent COVID-19 and there is
only extremely limited evidence that zinc lozenges are helpful. See the COVID-19 section
for details.
·
How much zinc should you take, and which form of zinc is best? The daily
requirement for zinc ranges from 3 mg for children to 14 mg for lactating women
(see Dosage). Zinc gluconate and zinc sulfate are
typically the least expensive, but amino acid chelates of zinc might be better
absorbed. To reduce the duration of a cold, take a lozenge (or other orally
dissolving formulation providing 9 to 23 mg of zinc as either zinc gluconate or
zinc acetate) every 2 to 3 hours during the day, allowing it to fully dissolve
in the mouth. Limit treatment to one week as large doses of zinc (see upper intake levels) can reduce copper
absorption and eventually lead to copper deficiency that can impair the
immune system.
·
What is the best zinc supplement or lozenge? Among supplements
that passed testing, we identified our Top Picks for pills and lozenges, as well as dissolving tablets, and liquids. We found that you can pay as little
as 1 cent or more than $1 to get an equivalent dose of high-quality zinc —
there is no need to overspend.
·
Cautions when taking zinc: As noted above, unless treating zinc
deficiency, don't take large doses (more than 40 mg) of zinc daily for more
than a week and don't take with fiber, which inhibits absorption of zinc. Be
aware of drug interactions with zinc, particularly for certain antibiotics.
(See Concerns and Cautions for more
information about zinc side effects, interactions, and safety).
What It Is:
Zinc is
an essential mineral, one of the few nutrients for which a number of people are
mildly deficient. Zinc deficiency is especially common in adolescents, infants,
seniors and women in general, although severe deficiency is rare in developed
countries.
Certain drugs and
nutrients can inhibit zinc absorption and/or increase its excretion (see "What to Consider When Using," below).
Thus, for many people, increasing the intake of zinc-containing foods or taking
a zinc supplement, either alone or as part of a multivitamin/multimineral, may
be a prudent form of nutritional insurance.
As a dietary supplement,
zinc is found in many forms, including zinc gluconate, zinc acetate, zinc
citrate, zinc sulfate, zinc chelates, zinc carbonate, zinc orotate, and zinc
picolinate. (See ConsumerTips™ for
information about the forms of zinc and foods that contain zinc.)
What It Does:
Zinc plays a role in brain function, wound healing, immune
function, sperm production, and vision maintenance. Zinc in pill or liquid form
may be taken in nutritional doses to replenish depleted zinc levels.
In zinc deficiency
Zinc deficiency can cause slowed growth in infants and children and impaired
immune function. Deficiency has also been associated with recurrent aphthous
stomatitis (canker sores) (Hamid, Int J Contemp Med Res
2017). Symptoms of severe deficiency can include hair loss,
diarrhea, impotence, weight loss, delayed healing of wounds, taste
abnormalities and loss of taste (NIH 2018; Schiffman, Eur J Clin Nutr 2000).
Zinc
deficiency can also cause an eczema-like rash, as was reported in a
4-month-old infant with zinc deficiency who developed a severe, red, round rash
on his abdomen, arms, legs, diaper area, face and scalp that cleared after five
days of supplementation with zinc sulfate. Recurrence was avoided with zinc
supplementation over the following year (Schröder, New Engl J Med 2020).
Among people who are
deficient in zinc (especially the elderly), some evidence suggests that such
replenishment might help increase immunity and prevent
respiratory tract infections. For example, a study of people in nursing
homes in France found that daily supplementation with zinc (20 mg from zinc
sulfate) along with selenium (100 mcg from selenium sulfide) at breakfast for
two years resulted more people being free of respiratory tract
infections and having better antibody responses after influenza
vaccination that those not supplemented with the minerals. Most of the
population, however, was initially slightly deficient in both zinc and
selenium, with mean zinc blood plasma levels steadily increasing from 70 mcg/dL
to about 80 mcg/dL in the supplemented group but remaining low for much of the
study in those not supplemented with the minerals (Girodon, Arch Int Med 1999). Similarly, an
analysis of data from the AREDS study (which focused on supplement
formulas to prevent eye disease) showed that the zinc (60 mg daily for 5 years)
was in the "protective direction for respiratory-specific mortality
compared with no zinc", although the finding was not statistically
significant (AREDS Rsch
Gp, JAMA Opthal 2004).
Zinc
deficiency can occur in people with Crohn's disease due to
malabsorption. In some people with Crohn's disease, deficiency can be corrected
with oral zinc supplementation, but in others, oral supplementation is not
well-tolerated or effective. For example, oral supplementation with zinc (220
mg of zinc sulfate taken three times daily) was reported to increase blood
levels of zinc to within the normal range and resolved skin lesions that
developed due to zinc deficiency in two men with Crohn's disease; however, one
of the men experienced stomach pain and vomiting with oral supplementation and
required intravenous supplementation (McClain, Gastroenterology 1980). In a study
among 61 children and adolescents with inflammatory bowel disease that included
40 participants with Crohn's disease, supplementation with a daily multivitamin
(providing 2.5 mg of zinc oxide) for one year normalized blood levels of zinc
in 63% of those who began the study with a zinc deficiency, while 37% remained
deficient. The study did not find any association between blood levels of zinc
and disease activity scores (Santucci, J Ped Gastroenterol Nutr 2014).
Supplementation is
particularly effective in reducing the duration and severity of diarrhea in
zinc-deficient individuals. Correcting zinc deficiency (and iron deficiency, if
also present) in people with recurrent canker sores was found to eliminate
recurrence of sores (Yildirimyan, Oral
Health Prev Dent 2019).
COVID-19
Due to zinc's anti-viral properties, role in the immune system, and the
potential benefit of zinc lozenges for colds (below), some websites have promoted the use of
zinc lozenges to help prevent or treat COVID-19, the infection
caused by the SARS-CoV-2 virus.
In a laboratory study,
zinc was shown to inhibit the replication of coronaviruses in cells (te
Velthuis, PLoS Pathog 2010). A
study in Spain among 249 people hospitalized with COVID-19 found that those
with very low blood levels of zinc (< 50 mcg/dL) upon admission were more
likely to have a severe case and more likely to die than those with zinc blood
levels above 50 mcg/dL (21% vs. 5% mortality rate, respectively) (Vogel-Gonzalez medRxiv
2020 -- preprint).
A physician in Washington
D.C. reported that four people with symptomatic COVID-19, but not hospitalized,
took zinc lozenges at various stages of the disease and each experienced
significant improvements after one day. Two took zinc citrate (23 mg zinc), one
took zinc citrate/zinc gluconate (23 mg zinc), and one took zinc acetate (15 mg
zinc). They had been instructed to take one lozenge every 2-4 hours and allow
it to dissolve on the tongue over 20-30 minutes, and not exceed 200 mg in a day
(Finzi, Int J Infect Dis 2020). Although intriguing, this
was not a controlled study and does not provide definitive evidence of a
benefit.
A study of 214 adults
diagnosed with COVD-19 in Ohio and Florida found that taking 50 mg of zinc at
bedtime daily did not significantly decrease the duration of
symptoms compared to high-dose zinc supplementation. There was also no benefit
from combining the zinc with high-dose (8,000 mg per day) vitamin C or from the
vitamin C alone (Thomas, JAMA Network Open 2021).
Nevertheless, having sufficient
blood levels of zinc is important for immune system health and, as discussed
above, in people somewhat deficient in zinc, taking an
appropriate amount of zinc (such a 20 mg daily) as a supplement may help
improve immune function and reduce the risk of respiratory infections. See
the ConsumerTips™ section
for more information about preventing and treating zinc deficiency. If you are
going to take zinc or use zinc lozenges, do not exceed the daily upper tolerable intake level (40 mg for
adults, less for children) for extended periods (i.e., more than a week).
For colds
Most, although not all, studies have shown that zinc lozenges can reduce
cold symptoms. Effectiveness appears to require a sufficient amount of zinc (9
to 23 mg as zinc gluconate or zinc acetate) per lozenge, slow dissolution (15
to 30 minutes), and frequency of dosing (6 to 10 lozenges per day), as noted
below.
A review of three
randomized, placebo-controlled, double-blind clinical trials involving
substantial total daily doses (80 mg to 92 mg) of zinc from lozenges (9 to 23
mg of zinc (from zinc acetate) per lozenge) given within 24 hours
of cold symptoms found that they shortened the duration of nasal discharge by
34%, nasal congestion by 37%, sneezing by 22%, scratchy throat by 33%, sore
throat by 18%, hoarseness by 43%, and cough by 46%. Interestingly, muscle ache
was also shortened by 54% but there was no difference in the duration of
headache or fever. (Hemila, BMC Family Practice 2015). A subsequent analysis of seven clinical trials in which zinc
lozenges were given within the first few days onset of a cold found that
both zinc gluconate or zinc acetate worked
equally as well in reducing the duration of colds, by an average of 33% (about
2 to 3 days) compared to placebo (Hemila, JMSR Open 2017).
The study also found that lower daily doses of zinc (80 mg to 92 mg elemental
zinc) were just as effective as higher daily doses (192 mg to 207 mg elemental
zinc); all doses were divided, and taken as 6-10 lozenges per day. NOTE: Zinc
at these high doses (all of which exceed the upper tolerable daily intake for
zinc) should generally not be taken for much longer than one week.
A study in Finland among
87 men and women (average age 49) found that a zinc lozenge (containing 13 mg
of zinc from zinc acetate) dissolved in the mouth five to six times daily
during the first five days of a cold did not shorten the
duration of colds compared to placebo. The researchers suggested that the lack
of benefit may have been due to the fact that most participants used five
rather than six lozenges per day (providing a daily total of 65 mg of zinc — a
lower dose than used in other studies, as discussed above) and that the
lozenges were smaller and dissolved more rapidly (8 minutes vs. 15 - 30 minutes)
than lozenges used in studies showing a benefit, allowing for less overall time
during which the mouth and throat were exposed to zinc (Hemila, BMJ Open 2020).
In children, zinc syrup
taken by mouth and swallowed may modestly help prevent and/or treat common
colds (including reductions in school absences and prescriptions for
antibiotics). (For more information about ingredients used to treat or prevent
colds see ConsumerTips™ below
and Product Reviews of Echinacea, Vitamin C, and Ginseng.)
For
vision
Zinc supplementation in high doses (69.6 mg daily) alone or at either a high or
low dose (21.8 mg per day) along with anti-oxidants (beta-carotene, vitamin C,
and vitamin E) slows the progression of advanced age-related
macular degeneration (AMD). The combination (but not zinc alone) also reduces
the risk of losing visual acuity in AMD. This was demonstrated in the large
Age-Related Eye Disease Study (AREDS) and subsequent AREDS2 (Age-Related Eye Disease Study 2) . However,
the AREDS formula failed to prevent the progression of early stage of
AMD as well as the progression of cataracts.
For
sleep
Zinc is involved in the regulation of sleep through its role in nerve
transmission in the brain, and higher levels of zinc in the blood have been
associated with better amounts of sleep in studies of infants, pre-adolescents,
and adults — although this does not establish a cause-and-effect relationship.
Several sleep studies in people involving zinc-containing formulas that include
other ingredients (such as melatonin and other
minerals) have shown promise in fostering sleep, but there have been no studies
with zinc alone. Increasing the amount of zinc in the blood from a supplement
does not necessarily increase levels of zinc in the brain — due to low
permeability of the blood-brain barrier for zinc. The most compelling human
evidence so far for zinc is a 3-month study in Japan that found that ingesting
50 grams of Pacific oyster (providing 15 mg of zinc) daily, reduced by 5
minutes the time to fall asleep and increased the time in non-REM sleep (a
measure of sleep efficiency) (Cherasse, Int J Molec Sci 2017). More research is
needed to determine if taking zinc aids sleep and, if it does, the proper
dosing.
See ConsumerTips™ for
considerations when buying these zinc-containing vision supplements.
For additional
information about supplements to treat or prevent macular degeneration vision
see ConsumerLab.com's Product Review of Lutein and Zeaxanthin Supplements.
Infertility
Zinc is essential for the production of sperm. Several small
studies in countries such as the Netherlands and Iran suggested that
supplementation with zinc and folic acid (also important for sperm production)
might improve sperm count or quality in healthy men and in those with fertility
issues, even if they are not deficient in these nutrients (Wong, Fertil Steril 2002; Azizollahi, J Assist Reprod Genet 2013). However,
a large study in the U.S. of over 2,000 men seeking infertility treatment with
their partners (about 80% of whom had a diagnosis of male infertility) found
that a combination of elemental zinc (30 mg) and high-dose folic acid (5 mg)
taken daily for six months did not significantly increase
sperm count or improve semen quality or couples' live birth rates compared to
placebo, although it was not noted if the men were deficient in either nutrient
prior to the study (Schisterman, JAMA 2019).
Diabetes
A meta-analysis of clinical studies that included people with or without type 2
diabetes found that zinc supplementation lowered fasting blood sugar levels
compared to controls, and the improvement was greater with low doses (below 25
mg/day) than with higher doses (25-75 mg/day). Low-dose zinc lowered fasting
blood sugar by 17.3 mg/dL, while high-dose zinc lowered fasting blood sugar by
only 5.27 mg/dL. Similarly, insulin resistance improved by a greater magnitude
compared to control for people given low-dose zinc than for those given
high-dose zinc. The meta-analysis also compared the effects of short-term
(<12 weeks) versus long-term (at least 12 weeks) zinc supplementation and
found that both durations of zinc supplementation improved HbA1c compared to controls,
but the effect was greater with long-term supplementation (Pompano, Adv Nutr
2020). Unfortunately, data was not available to determine how zinc
status (e.g., were people deficient in zinc or not) affected levels of
improvement.
Cholesterol Effects
As part of the same meta-analysis noted directly above, zinc taken in low doses
(below 25 mg/day) and for longer durations (at least 12 weeks) reduced
triglyceride levels, total cholesterol levels, and low-density lipoprotein (LDL
or "bad") cholesterol levels better than controls. Zinc
supplementation did not improve high-density lipoprotein (HDL or
"good") cholesterol compared to controls, regardless of dose or
duration of treatment (Pompano, Adv Nutr
2020).
Other
uses
Zinc may be helpful in Wilson's disease, a disorder where too much copper
builds in the body's tissues, as zinc reduces copper levels. Other ways in
which high-dose zinc may help, include enhancing the effectiveness of
antidepressants and improving symptoms of acne, anorexia nervosa, sickle cell
anemia, altered taste sensation (of various origins), and attention
deficit-hyperactivity disorder (ADHD). Be aware that high doses of zinc can
have adverse effects. (See ConsumerTips™ for
dosage and safety issues regarding zinc supplements).
The balance of current
evidence fails to support the use of zinc for cataracts, rheumatoid arthritis
or eczema. The use of zinc in high or low doses for benign prostatic
hyperplasia (BPH), peptic ulcers, osteoporosis, Crohn's disease, tinnitus
(ringing in the ear), mouth and skin irritation during radiation therapy for
head and neck cancer, and many other conditions for which it is often
recommended remains highly speculative.
Quality Concerns and
Tests Performed:
No
government agency routinely tests zinc or other dietary supplements for their
contents or quality. ConsumerLab.com purchased and evaluated zinc supplements
sold in the U.S. and Canada to determine whether they contained the amounts of
zinc stated on their labels. All products were tested for arsenic, cadmium, and
lead -- potential contaminants. All non-chewable, non-sublingual tablets and
caplets were also tested to be sure that they would properly disintegrate to
enable their absorption. (See How Products Were Evaluated for
information on testing methods and passing score.)
What CL Found:
Zinc Per Serving
Every product other than Zicam Cold Remedy listed the amount
of zinc it provided per serving, and each contained that promised amount, which
ranged from 5 mg to 50 mg, as shown below. We found that Zicam provided
10.2 mg of zinc per quick dissolve tablet.
Zinc pills
The zinc pills provided 15 mg to 50 mg of zinc per pill and total suggested
daily servings of up to 60 mg. As noted in the table below, 40 mg of zinc per
day is the Upper Tolerable Intake Level for zinc for adults and several
products exceeded this level, above which there is increasing risk of toxicity,
particularly from copper deficiency that can occur with long-term use.
Nevertheless, these amounts are in the correct range for treating zinc
deficiencies or providing high dose zinc to potentially treat or prevent
various conditions (see What to Consider When Using in the ConsumerTips™ section) and may be helpful under medical
supervision.
Too Much Zinc?
The Upper Tolerable Intake Level (UL) for zinc for adults is 40 mg and several
products exceed this level in a single serving, and some suggest multiple
servings per day (as this appears to be necessary for lozenges to be effective
by keeping the throat coated with zinc). Those that potentially exceed the UL
are noted in the Results table below (look for ">UL" in the 2nd column). In fact, Nature's Way
Zinc Lozenges suggests up to 6 lozenges per day, providing as much as
138 mg of zinc daily! Be aware that with long-term use (several weeks),
consuming more than 40 mg per day of zinc can cause copper deficiency, because
zinc competes with copper for absorption. Nevertheless, these high amounts can
be helpful, short-term, to treat zinc deficiency or treat or prevent various
other conditions (see What to Consider When Using) and may be
helpful under medical supervision.
If you are looking for a
supplement to provide only the recommended daily intake of zinc, which ranges
from 3 mg to 14 mg depending on your age and gender (see What to Consider When Using), you may be
better off taking a low-dose multivitamin — most include zinc at an appropriate
dose (see the table in our Multivitamin Review which compares
amounts of zinc across products).
Ability to Break Apart
We checked whether regular tablets and caplets could disintegrate (break apart)
within 30 minutes while being agitated water heated to body temperature -- a
USP requirement -- to assure that the zinc would be released in the body. The
only product that did not meet this requirement was MegaFood
Zinc, which took an extra 20 minutes.
Heavy Metal Contamination
All products were tested for heavy metals (arsenic, cadmium, and lead) and none
was found to exceed reasonable contamination limits.
Cost
Some products provide zinc at much lower cost than others. As shown below, we
found the cost to obtain a 30 mg dose of zinc ranged from as little as 1 cent
from Swanson Zinc Gluconate to $1.17 from Zicam Cold
Remedy -- with Mary Ruth's Liquid Ionic Zinc close
behind at $1.16. Not surprisingly, more expensive products tended to be those
made from foods, such as Garden of Life and MegaFood, or with special formulations. However, it
is hard to justify higher prices between similar products, like paying more
than twice as much for the same amount of zinc gluconate from cherry-flavored
lozenges from Cold-Eeze compared
to Walgreens. As noted in the ConsumerTips™ section,
however, there is some preliminary evidence that amino acid chelate forms of
zinc may be more effective at raising zinc levels than other forms (although,
as discussed above, zinc gluconate and zinc acetate are the most
well-researched for use in lozenges for colds).
Top Picks:
·
For 50 mg strength: Swanson Zinc
Gluconate which provides 50 mg of zinc per capsule for 2 cents.
·
For 30 mg strength: Vitacost
Chelated Zinc Glycinate 30 mg, which costs 3 cents per capsule.
Zinc Lozenges/Orally Dissolving Tablets (to shorten colds): Walgreens
Zinc Lozenges — Cherry Flavor (17 cents per lozenge)
Clinical studies have
shown a reduction in cold symptoms with lozenges containing 9 mg to 23 mg of
zinc (in the gluconate or acetate forms) taken every two hours
while awake (with total daily intake of 75 mg or more of zinc from lozenges).
Only two lozenges meet these criteria — Walgreens and Cold—Eeze, each of which provides about 13 mg of zinc from
zinc gluconate. Zicam Cold Remedy RapidMelt tablets,
which we found to provide 10.2 mg of zinc from a combination of the gluconate
and acetate forms, also meets this criteria, but it disintegrates quickly, so
it would not seem to coat the throat for as long as the lozenges (which are
hard candies). We also don't like that Zicam doesn't list its
amount of zinc — so the amount could vary from lot-to-lot. This is also why it
is not listed as Approved, but as "N/A" — not applicable.
The Walgreens and Cold-Eeze lozenges are essentially the same, but Walgreens costs
much less (17 cents versus 39 cents per lozenge), leading us to prefer Walgreens.
Note that all three of these products are marketed "homeopathic" OTC
drugs, as opposed to dietary supplements, which legally allows them to make
claims regarding shortening colds, although they contain the same types of zinc
that can be found in supplements.
The other lozenges do not
meet the criteria as they contain zinc from zinc citrate. They also each
contain sorbitol and/or mannitol, ingredients that could potentially reduce the effectiveness of zinc for
treating colds.
Zinc Liquid: Good State Natural Ionic Zinc (16
cents per 10 drops, providing 15 mg of zinc)
We prefer Good
State to Mary Ruth's Liquid Ionic Zinc for two reasons: They both
provide zinc sulfate but Good State is much less expensive (Mary
Ruth's costs 42 cents for 11 mg of zinc — so more than 3 times the
cost per milligram of zinc), and, when mixed into 12 ounces of water as
directed, Good State is essentially tasteless while Mary
Ruth's, which is taken straight, has an astringent (mouth-drying) effect,
initially hidden by the sweetness of added glycerin.
Test Results by Product:
Listed
alphabetically below are the test results for 19 zinc products. ConsumerLab.com
selected 13, and six others (each indicated with CL flask) were tested at the
request of their manufacturers/distributors through CL's Quality Certification Program and
are included for having passed testing.
Shown for each product is
information about the amount of zinc per serving, the labeled serving size and
suggested daily servings, and the results of our tests for zinc, heavy metals,
and pill disintegration. Price and cost comparisons are in the fourth column,
other notable features are in the fifth column, and the full list of
ingredients is in the final column.
Results of
ConsumerLab.com Testing of ZINC PRODUCTS
(Click arrows or swipe left or right to see all columns)
Approval Status
Product Name
(Suggested Serving on Label)
Claimed Amount of Zincⓘ
(Form of Zinc)
Pill Sizeⓘ
Tasteⓘ
Heavy Metalsⓘ
Disintegration
Suggested Serving on Label
Cost for Suggested Serving
[Cost Per 30 mg Zinc]
Priced
Notable Features
Full List of Ingredients Per Serving
Zinc Pills:
APPROVED
Garden of Life® Vitamin Code® Raw Zinc™
Dist. by Garden of Life LLC
2 vegan capsules
30 mg zinc
(from brown rice chelate)
✔
Large vegan capsule
Heavy
Metals: Pass
Disintegration: NA
Adults take 2 capsules daily.
$0.35/2 vegan capsules
[$0.35]
$10.49/60 vegan capsules
2 vegan capsules
Vitamin C 60 mg, RAW organic fruit & vegetable blend 166 mg, trace mineral
blend 150 mg, RAW probiotic & enzyme blend 60 mg
Non GMO Project Verified seal. NSF Certified Gluten-Free. Certified Vegan
Vegan.org.
2 vegan capsules
Vitamin C (from culture of Saccharomyces cerevisiae) 60 mg, Zinc
(from Brown Rice Chelate) 30 mg, RAW Organic Fruit & Vegetable Blend
[Organic Apple (fruit), Organic Beet (root), Organic Broccoli (stalk &
flower), Organic Carrot (root), Organic Spinach (leaf), Organic Tomato (fruit),
Organic Strawberry (fruit), Organic Tart Cherry (fruit), Organic Blackberry
(fruit), Organic Green Bell Pepper (fruit), more...
APPROVED
Life Extension® Zinc Caps 50 mg
Dist. by Quality Supplements and Vitamins, Inc.
1 vegetarian capsule
50 mg>UL zinc
(OptiZinc® zinc monomethionine,
zinc citrate)
✔
Large vegetarian capsule
Heavy
Metals: Pass
Disintegration: NA
Take 1 capsule daily, or as recommended by a
healthcare practitioner.
$0.08/vegetarian capsule
[$0.05]
$6.75/90 vegetarian capsules
Gluten Free. Non GMO.
1 vegetarian capsule
Zinc (as OptiZinc® zinc monomethionine,
zinc citrate) 50 mg.
Other Ingredients: Microcrystalline cellulose, vegetable cellulose (capsule),
vegetable stearate, silica.
NOT APPROVED
MegaFood® Zinc
Mfd. by MegaFood
1 tablet
22.5 mg zinc
(mineral bound S. cerevisiae)
✔
Medium circular tablet
Heavy
Metals: Pass
Disintegration: Required longer than 30 minutes to fully disintegrate (took 50 minutes)
1 tablet daily.
$0.30/tablet
[$0.40]
$17.83/60 tablets
1 tablet
Nourishing food blend 63 mg
Non GMO Project Verified seal. NSF Certified Gluten-Free. Certified Vegan
Vegan.org. Kosher. Dairy Free. Soy Free. Glyphosate residue free. Tested for
125+ pesticides and herbicides.
1 tablet
Zinc (mineral bound S. cerevisiae) 22.5 mg, Nourishing Food Blend
[Organic Spinach Leaf, S. cerevisiae, Organic Brown Rice, Organic
Parsley Leaf, Organic Carrot, Organic Broccoli, Organic Beetroot] 63 mg.
Other Ingredients: Cellulose, Stearic Acid, Silica.
APPROVED
Nature's Bounty® Zinc 50 mg
Mfd. by Nature's Bounty, Inc.
1 caplet
50 mg>UL zinc
(zinc gluconate)
✔
Medium/large caplet
Heavy
Metals: Pass
Disintegration: Pass
For adults, take 1 caplet daily, preferably with
a meal.
$0.07/tablet
[$0.04]
$6.99/100 caplets
Non-GMO, No Artificial Color, No Artificial
Flavor, No Artificial Sweetener, No Preservatives, No Sugar, No Starch, No
Milk, No Lactose, No Soy, No Gluten, No Wheat, No Yeast, No Fish. Sodium Free.
Suitable for Vegetarians.
1 caplet
Zinc (as Zinc Gluconate) 50 mg.
Other Ingredients: Vegetable Cellulose, Dicalcium Phosphate. Contains <2%
of: Silica, Vegetable Magnesium Stearate, Vegetable Stearic Acid.
APPROVED
NOW® L-OptiZinc® 30 mg
Dist. by Now Foods
1 veg capsule
30 mg zinc
(L-OptiZinc® Monomethionine)
✔
Medium/large veg capsule
Heavy
Metals: Pass
Disintegration: NA
Take 1 capsule daily.
$0.06/veg capsule
[$0.06]
$6.32/100 veg capsules
1 veg capsule
Copper 0.3 mg
Kosher. Not Manufactured with wheat, gluten, soy, milk, egg, fish, shellfish
or tree nut ingredients.
1 veg capsule
Zinc (from L-OptiZinc® Monomethionine)
30 mg, Copper (from Copper Amino Acid Chelate) 0.3 mg.
Other Ingredients: Rice Flour, Cellulose (capsule) and Stearic Acid (vegetable
source).
APPROVED
Sundown® Essential Zinc 50 mg
Mfd. by Rexall Sundown, Inc.
1 caplet
50 mg>UL zinc
(zinc gluconate)
✔
Medium/large caplet
Heavy
Metals: Pass
Disintegration: Pass
For Adults, Take 1 Caplet Daily, Preferably With
A Meal.
$0.09/caplet
[$0.06]
$9.22/100 caplet
Non-GMO. No Gluten. No Wheat. No Milk. No
Lactose. No Artificial Color. No Artificial Flavor. No Artificial Sweetener. No
Preservatives. No Sugar. No Soy. No Starch. No Yeast. No Peanuts. No Tree Nuts.
No Fish. Sodium Free.
1 caplet
Zinc (from zinc gluconate) 50 mg.
Other Ingredients: Vegetable Cellulose, Dicalcium Phosphate. Contains <2%
of: Silica, Vegetable Magnesium Stearate, Vegetable Stearic Acid.
APPROVED
Top Pick
for 50 mg Strength
Swanson® Zinc Gluconate
Dist. by Swanson Health Products
1 capsule
50 mg>UL zinc
(zinc gluconate)
✔
Large capsule
Heavy
Metals: Pass
Disintegration: NA
Take one capsule per day with food and water.
$0.02/capsule
[$0.01]
$4.55/250 capsules
None.
1 capsule
Zinc (from zinc gluconate) 50 mg.
Other Ingredients: Rice flour, gelatin, magnesium stearate.
APPROVED
Thorne® Zinc Picolinate 30 mg
Mfd. by Thorne Research, Inc.
1 capsule
30 mg zinc
(zinc picolinate)
✔
Medium/large capsule
Heavy
Metals: Pass
Disintegration: NA
Take 1 capsule daily or as recommended by your
health-care practitioner.
$0.18/capsule
[$0.18]
$33.00/180 capsules
Gluten Free.
1 capsule
Zinc (as Zinc Picolinate) 30 mg.
Other Ingredients: Microcrystalline Cellulose, Hypromellose (derived from
cellulose) capsule, Leucine, Silicon Dioxide.
APPROVED
Top Pick
for 30 mg Strength
Vitacost® Chelated Zinc Albion®
Zinc Glycinate Chelate
Dist. by Vitacost.com, Inc.
1 capsule
30 mg zinc
(zinc glycinate chelate)
✔
Medium/large capsule
Heavy
Metals: Pass
Disintegration: NA
Take 1 Capsule Daily With Food Or As Directed By
A Healthcare Professional.
$0.03/capsule
[$0.03]
$5.99/180 capsules
1 capsule
Proprietary blend 45 mg
Free Of: Milk, Eggs, Peanuts, Tree Nuts, Crustacean Shellfish, Fish, Soy,
Gluten, Titanium Dioxide.
1 capsule
Zinc (as zinc glycinate chelate) TRAACS® 30 mg, Proprietary Blend (Short Chain Fructooligo-saccharides (FOS) NutraFlora®,
Ginger Root Extract (standardized to 5% gingerols), Black Pepper Powder
(fruit), Long Pepper Powder (fruit), Multi-Enzyme Complex (amylase, fungal
lactase, protease, lipase, cellulase) DigeZyme®) 45
mg.
Other Ingredients: Rice Flour, Gelatin And Vegetable Magnesium Stearate.
APPROVED
The Vitamin Shoppe® Zinc 50 mg
Dist. by Vitamin Shoppe, Inc.
1 capsule
50 mg>UL zinc
(zinc gluconate, zinc oxide, zinc aspartate)
✔
Large capsule
Heavy
Metals: Pass
Disintegration: NA
Take 1 capsule daily, preferably with a meal.
$0.07/capsule
[$0.04]
$21.99/300 capsule
Gluten-Free. Dairy-Free. Soy-Free. Nut-Free.
Does Not Contain: Sugar, Salt, Preservatives, Artificial Colors or Flavors.
1 capsule
Zinc (as zinc gluconate, oxide, aspartate) 50 mg.
Other Ingredients: Rice flour, gelatin, magnesium stearate.
Zinc Lozenges:
APPROVED
Carlson® Zinc Ease® - Natural Lemon Flavor
Dist. by Carlson Division of J.R. Carlson
Laboratories, Inc.
1 lozenge
10 mg zinc
(zinc citrate)
✔
Medium/large circular lozenge
Mildly sweet tablet with mild lemon flavor, no metallic taste
Heavy
Metals: Pass
Adults: dissolve one lozenge in mouth every 2-3
hours up to three times per day.
$0.10/lozenge
[$0.31]
$8.64/84 lozenges
Gluten-free. No Artificial Preservatives.
1 lozenge
Total Carbohydrate 1 g, Sugar Alcohol <1 g, Zinc (from zinc citrate) 10 mg.
Other Ingredients: Sorbitol, stearic acid (veg.), magnesium stearate (veg.),
natural lemon flavor.
APPROVED
Cold-Eeze® - Cherry
Dist. by Mylan Consumer Healthcare, Inc.
1 lozenge
13.3 mg>UL zinc
(zincum gluconicum 2x [zinc
gluconate glycine])
✔
Large lozenge
Mildly sweet hard candy with mild cherry flavor, faint metallic taste
Heavy
Metals: Pass
Adults and children 12 years and over: take
Cold-EEZE® lozenge in mouth (do not chew). Repeat every 2-4 hours as needed
until all symptoms subside. Recommended daily dosage is 6 lozenges for adults
and 4 lozenges for ages 12-17.
$0.39/lozenge
[$0.87]
$6.98/18 lozenges
No artificial colors or preservatives. Gluten
free. Homeopathic. This product has no expiration date.
1 lozenge
Zincum Gluconicum 2x (13.3
mg Zinc).
Inactive Ingredients: Corn syrup, glycine, natural flavors and sucrose.
APPROVED
Country Life® Zinc Lozenges - Cherry Flavor
Mfd. by Country Life, LLC
1 lozenge
23 mg>UL zinc
(zinc gluconate, zinc citrate)
✔
Medium/large circular lozenge
Mildly sweet tablet, no metallic taste
Heavy
Metals: Pass
Adults allow 1 zinc lozenge to dissolve in mouth
before swallowing. Do not take more than 2 lozenges in 1 day.
$0.13/lozenge
[$0.18]
$8.09/60 lozenges
1 lozenge
Vitamin C 100 mg, sodium 5 mg
Halal. Kosher. Gluten Free. Vegan. No Yeast Or Wheat. No Soy Or Milk. No
Preservatives. No Artificial Flavors Or Colors.
1 lozenge
Calories 5, Total Carbohydrate 1 g, Total Sugars [Includes 1 g Added Sugars] 1
g, Vitamin C (as ascorbic acid, sodium ascorbate) 100 mg, Zinc (as zinc
gluconate, zinc citrate) 23 mg, Sodium (as sodium ascorbate) 5 mg.
Other Ingredients: Non GMO fructose, glucose, sorbitol, starch, stearic acid,
magnesium stearate, silica, cellulose, natural cherry flavor, citric acid, dark
sweet cherry fruit powder, maltodextrin.
APPROVED
Nature's Way® Zinc Lozenges - Wild Berry
Flavored
Dist. by Nature's Way Brands, LLC
1 vegan lozenge
23 mg>UL zinc
(zinc citrate, zinc gluconate)
✔
Medium/large circular vegan lozenge
Sweet tablet with slightly tart berry flavor, no metallic taste
Heavy
Metals: Pass
Take 1 lozenge every two hours, up to 6 lozenges
daily.
$0.07/vegan lozenge
[$0.09]
$4.21/60 vegan lozenges
1 lozenge
Vitamin C 100 mg, Echinacea purpurea 20 mg
Vegan. Contains no yeast-derived ingredients, wheat, soy, dairy products, or
preservatives.
1 lozenge
Total Carbohydrate 1 g, Vitamin C (ascorbic acid) 100 mg, Zinc (as zinc citrate
and gluconate) 23 mg, Echinacea purpurea (stem, leaf, flower)
20 mg.
Other Ingredients: Sorbitol, fructose, mannitol, natural flavor, sodium
bicarbonate, magnesium stearate, French vanilla flavor, stevia leaf extract.
APPROVED
Top Pick
for Lozenge
Walgreens Zinc Lozenges - Cherry Flavor
Dist. by Walgreen Co.
1 lozenge
13.4 mg>UL zinc
(zincum gluconicum 2x [zinc
gluconate glycine])
✔
Large lozenge
Mildly sweet hard candy with mild cherry flavor, faint metallic taste
Heavy
Metals: Pass
Adults and children 12 years and over: for best
results, begin treatment at start of symptoms (within 24-48 hours of onset).
Completely dissolve lozenge in mouth (Do not swallow whole. Do not chew.)
Repeat every 2-4 hours as needed until all symptoms subside. Do not exceed 6
lozenges for adults and 4 lozenges for children ages 12-17 in a 24 hour period.
$0.17/lozenge
[$0.37]
$2.99/18 lozenges
Homeopathic.
1 lozenge
Zincum Gluconicum 2x (13.4
mg Zinc).
Inactive Ingredients: Corn starch, corn syrup, glycine, medium chain
triglycerides, natural flavors, purified water, soybean oil and sucrose.
Other Orally Dissolving Formulations:
APPROVED
Frunutta® Zinc + Vitamin C
Mfd. by Frunutta®, LLC
1 instant dissolve tablet
5 mg zinc
(zinc oxide, zinc gluconate)
✔
Medium circular instant dissolve tablet
Small, somewhat sweet and metallic-tasting tablet that disintegrates in a
few seconds
Heavy
Metals: Pass
For children less than 4 years of age dissolve
one Micro Quick Absorb® Tablet in food or use as directed by the child's
provider. For children 4 or more years of age dissolve one Micro Quick Absorb®
Tablet under the tongue daily.
$0.17/instant dissolve tablet
[$1.00]
$14.99/90 instant dissolve tablets
1 instant dissolve tablet
Vitamin C 15 mg, stevia leaf extract 2 mg
1 instant dissolve tablet
Vitamin C (as ascorbic acid) 15 mg, Zinc (as zinc oxide and zinc gluconate) 5
mg, Stevia Leaf Extract (as rebaudioside A) 2 mg.
Other Ingredients: Lactose (Milk), natural cherry flavor and acacia gum.
N/Aⓘ
Zicam Cold Remedy - Citrus Flavor
Dist. by Matrixx
Initiatives, Inc.
1 quick dissolve tablet
No claimed amount of zinc
(zincum aceticum 2x, zincum gluconicum 1x [zinc
gluconate glycine])
Found: 10.2 mg>UL zinc
Medium/large circular quick dissolve tablet
Sweet, orange-flavored tablet that rapidly disintegrates
Heavy
Metals: Pass
Adults and children 12 years if age and older:
take 1 tablet at the onset of symptoms. Dissolve entire tablet in mouth. Do not
chew. Do not swallow while. Repeat every 2-3 hours, not to exceed 7 tablets in
24 hours. Take until symptoms are gone.
$0.40/quick dissolve tablet
[$1.17 based on amount found]
$9.97/25 quick dissolve tablets
Homeopathic.
1 quick dissolve tablet
Zincum aceticum 2x, Zincum gluconicum 1x.
Inactive Ingredients: Ascorbic acid, crospovidone,
FD&C yellow no. 6 aluminum lake, magnesium stearate, mannitol,
mono-ammonium glycyrrhizinate, natural and artificial flavor, sodium starch
glycolate, stearic acid, sucralose.
Liquid Zinc:
APPROVED
Top Pick
for Liquid
Good State Natural Ionic Zinc
Mfd. by Nano Ionic Manufacturing
10 drops [0.5 ml]
15 mg zinc
(zinc sulfate)
✔
Mixed in water as directed, has a very faint metallic taste
Heavy
Metals: Pass
Adults: Take 10 drops daily with 12 oz. water or
juice. Children: Take 5 drops daily with 8 oz. water or juice.
$0.16/10 drops
[$0.32]
$18.99/2 fl oz [29.1 ml] bottle (approx. 118
servings)
Front label claims "30,000 PPM."
Although not defined, this apparently refers to the product containing 30,000
mcg/g of zinc. This is approximately 30,000 mcg/ml or 30 mg/ml. The serving
size of 10 drops is approximately 0.5 ml, providing 15 mg of zinc.
10 drops
Zinc (from Zinc Sulfate) 15 mg.
Other Ingredients: Ultra pure water.
APPROVED
Mary Ruth's® Liquid Ionic Zinc - Unflavored
Dist. by Mary Ruth Organics LLC
6 pumps [3 ml]
11 mg zinc
(zinc sulfate)
✔
Sweet, glycerin-tasting liquid with a strong astringent (drying) effect on
the mouth and throat
Heavy
Metals: Pass
Adults & Children (4 years and up): 6 pumps
(11 mg); Children (1-3 years): 2 pumps (3 mg); Infants (thru 12 months): 2
pumps (3 mg); Pregnant/Lactating: 7 pumps (13 mg).
$0.42/6 pumps
[$1.16]
$16.99/4 fl oz [120 ml] bottle (approx. 40 servings)
Non GMO. Vegan. Sugar Free. Gluten Free. Corn
Free. Nut Free. Soy Free.
6 pumps
Zinc (as Zinc Sulfate) 11.25 mg.
Other Ingredients: Organic Glycerin and Purified Water.
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™:
Getting Zinc:
From food:
Oysters have very high zinc content (about 8 mg zinc per oyster). Other forms
of shellfish, as well as organ meats, beef, pork and chicken can provide 1-8 mg
of elemental zinc per serving. Whole grains, legumes, nuts and seeds provide
zinc as well, ranging in amounts from 0.2 to about 3 mg per serving, but the
high phytic acid (phytate) content of these foods may reduce the zinc's
availability. Many breakfast cereals and nutrition bars are also fortified with
zinc.
From supplements:
Zinc supplements come in various forms, known as zinc salts or complexes and
include zinc sulfate, zinc acetate, zinc gluconate, zinc citrate, zinc
picolinate, zinc bis-glycinate, and zinc methionine, among others. In general,
water-soluble salt forms of zinc — including zinc gluconate, zinc acetate, zinc
citrate and zinc sulfate — tend to be absorbed to similarly well, while
zinc oxide is not absorbed as well as these forms (Gupta, J Hum Nutr Diet 2020).
Although not conclusive, zinc chelated with amino acids seem to be absorbed
better than zinc chelated with organic acids such as citric acid (used to make
zinc citrate) or gluconic acid (used to make zinc gluconate), although zinc
chelated with picolinate, which is not an amino acid, is also well absorbed (Chen, Biofactors 2006).
For
example, one small, preliminary study found that an amino acid chelate of zinc
(zinc bis-glycinate) increased the bioavailability of zinc by 43% when compared
to zinc gluconate (Gandia, Int J Vitam Nutr Res 2007). Another small study in healthy, fasting adults found that
taking 25 mg of zinc as zinc methionine (OptiZinc,
InterHealth Corp.), which is also an amino acid
chelate of zinc, increased blood levels of zinc two-hours later about 30% more
than the same amount of zinc from zinc sulfate. However, when taken with a meal
containing phytate, which impairs zinc absorption, no difference in zinc
absorption was observed between these forms (Rosado, Nutr
Res 1993). A third small study found that taking
50 mg of zinc as zinc picolinate in three divided doses daily between meals for
four weeks increased hair, urine, and red blood cell levels of zinc, while
taking the same dose of zinc as zinc citrate or zinc gluconate did not (Barrie, Agents Action 1987).
The body tends to
regulate zinc absorption, absorbing more when zinc levels are low and less when
zinc levels are high. Note that there is a difference between the milligrams of
pure zinc in a product ("elemental zinc") and the total amount of the
zinc salt. In this article and product list, we use numbers based on the
elemental zinc itself, not the salt.
What to Consider When Using:
To prevent or treat deficiency:
Dose: Mild zinc deficiency is fairly common. Zinc deficiency is difficult to
define due to how zinc is stored in the body, but a general cut-off for
deficiency based on blood plasma levels is about 70 mcg/dL (or 10.7 micromols/L) (Maxfield, StatPearls 2019).
The Recommended Dietary Allowance (RDA) of zinc is 3 mg for children ages 1 to
3, 5 mg for those 4 to 8, and 8 mg for those 9 to 13. For males 14 and older
the RDA is 11 mg. For females 14 to 18 it is 9 mg, while for those 19 years and
older it is 8 mg per day. The RDA for pregnant women who are 18 years or
younger is 13 mg, while it is 11 mg for pregnant women 19 years and older. For
lactating women the RDAs are 14 mg if 18 years and younger or 12 mg if 19 years
or older.
Causes of zinc
deficiency:
·
High fiber foods may interfere with zinc supplement absorption
if the foods and the supplement are taken at the same time.
·
Taking zinc with milk may also decrease the absorption of zinc,
possible due to the casein protein in milk (Yildirimyan, Oral
Health Prev Dent 2019) or
because calcium in milk may compete for absorption with
zinc.
·
Certain drugs may increase the need for zinc supplements, such
as ACE inhibitors, thiazide diuretics and medications that reduce stomach acid
(such as Prilosec or Pepcid).
·
Hypothyroidism (as can occur in Hashimoto's disease) can cause
zinc deficiency because thyroid hormones are essential for zinc absorption.
Zinc deficiency, itself, can cause subclinical hypothyroidism because zinc is
needed to make thyroid hormones. Zinc supplementation has been shown to improve
symptoms (including hair loss) in cases of hypothyroidism (Ambooken, Int J Trich
2013).
·
Vegetarians may require as much as 50% more of the RDA for zinc
than non-vegetarians, due to phytates in legumes and grains that can interfere
with zinc absorption (Institute of Medicine, Food and
Nutrition Board. 2001, p. 480).
For colds:
Although more research is needed to determine optimal dose and formulation,
most, but not all, studies suggest that when zinc is taken in the form of a
lozenge or nasal gel (as opposed to an oral supplement), it can directly kill
cold viruses and thereby shorten the duration of a cold. Only zinc
gluconate and zinc acetate have been shown to be effective for this purpose,
although other forms of zinc are available on the market in lozenges. It is
thought that certain flavorings that may be added to lozenges, such as citric
acid and tartaric acid, can interfere with zinc's antiviral action. They may
bind zinc ions, making them less available. (Also for this reason, foods and
beverages containing citric acid should be avoided within one hour of taking
zinc lozenges (Garland, Ann Pharmacother
1998). There is also experimental evidence that mannitol and
sorbitol bind zinc ions in the presence of saliva (Zarembo, J Pharm Sci 1992). The flavorings
(sweeteners) dextrose and sucrose are thought not to interfere. Products are
available in which zinc is mixed with a great variety of other substances, such
as herbs or vitamin C, but these have not been tested for their combined
efficacy.
A
typical dose of the lozenge form of zinc is 9 to 23 mg of zinc given every 2 to
3 hours (2 hours for the lower dose) during the day while symptoms persist. Analyses of lozenge
studies suggests that the total daily dose may need to exceed 75 mg to be
effective (Hemila, Open Acc Resp Med J 2011), such as 80
mg to 92 mg, but higher amounts (192 mg to 207 mg) are no more effective (Hemila, JMSR Open 2017). It is important not
to take this much zinc for more than a week or so, as this amount greatly
exceeds the tolerable intake levels discussed below (see Concerns and Cautions). It is possible that
concern over excess zinc is the reason why several products on the market
provide only 5 mg per lozenge and suggest a dose of only one or two lozenges
per day. However, zinc lozenges are not likely to help a cold if taken this
way, so you may need to use these more frequently. Some people get an upset
stomach from the lozenges.
Because zinc lozenges
need to act in the throat, let the lozenge dissolve fully — do not chew it or
swallow it whole. Interestingly, although they act in the throat, a review of
studies suggests that the beneficial effects of lozenges extend to other areas,
including the nose and muscles (Hemila, BMC Family Practice 2015).
In children, zinc sulfate
syrup in a dose of 15 mg of zinc per day may help prevent colds and 30 mg of
zinc per day at the first onset of symptoms may help treat a cold, although the
benefits appear to be modest. In the seven-month study from which these results
were reported, side effects were minor and similar among the zinc-treated kids
and those treated with placebo (sugar pills). However, the kids in the study
were not monitored for signs of zinc overload or other potentially serious side
effects of taking high doses of zinc for many months. Doses exceeding the UL
for children should only be used under physician supervision.
To
prevent macular degeneration: As noted earlier, AREDS (Age-Related Eye Disease Study)
found that zinc alone or with anti-oxidants can slow the progression of
age-related macular degeneration (AMD) when taken on a daily basis. The tablets
used in AREDS were manufactured to contain the following minimum contents
throughout their shelf-life: 7160 IU of vitamin A (beta carotene), 113 mg of
vitamin C (ascorbic acid), 100 IU of vitamin E (dl-alpha tocopheryl
acetate), 17.4 mg of zinc (zinc oxide), and 0.4 mg of copper (cupric oxide).
Four tablets were taken daily, providing a total of 28,640 IU of vitamin A, 452
mg of vitamin C, 400 IU of vitamin E, 69.6 mg of zinc, and 1.6 mg of copper.
(The copper in the formula was included to prevent zinc-induced copper
deficiency — see Concerns and Cautions below.) [NOTE: Some
articles about AREDS report suggest that the supplement used contained slightly
higher amounts of ingredients, such as 80 mg of zinc per day, but the actual
specifications for the product are those described above.] In May 2013, results
from the AREDS2 (Age-Related Eye Disease Study 2) study were
published. This study was similar to the first AREDS trial, but tested
variations of the original supplement formula. When researchers reduced the
amount of zinc from 69.6 mg to 21.8 mg, there were no changes in the beneficial
effects for reducing risk of disease progression of AMD. This suggests products
with lower amounts of zinc may be just as effective, with potentially fewer
zinc-related side effects.
Other compounds that may
improve eye health are lutein and zeaxanthin. Based on AREDS2, lutein and
zeaxanthin may be preferable to beta-carotene found in some vision formulas.
For a complete review see Product Review of Lutein and
Zeaxanthin.
To
treat acne: Some evidence suggests that 30 mg of zinc taken orally each day may
be helpful for acne. This is a safe dose for most people. However, in many
studies of zinc for acne, a much higher dose was used: 90 mg daily or more (Dhaliwal, Am J Clin Derm 2020). Doses this high should only be used
under physician supervision (see Concerns and Cautions below).
"Zinc
Challenge" Taste Test
Although not tested this year, in our last review of zinc supplements, we
included a liquid called Designs for Health Zinc Challenge. Based
on its label it was is meant as a zinc supplement. However, it seems to be
indirectly promoted as a "taste test" for zinc
deficiency in the Help section of the Designs for Health website, which
describes a "zinc challenge" to
"find out if your zinc levels are low." This is an unproven
test and may be misleading.
According information
that was on the Designs for Health website, "To perform the test, put
about 2 Tablespoons of zinc liquid into a cup and then into your mouth. Hold it
in your mouth for up to 30 seconds to see if a definite taste develops, and
then swallow." If no immediate taste or sensation is noticed, or if,
"after a few seconds a slight taste variously described as
"dry," "mineral," "furry," or "sweet,"
develops," this "suggests a zinc deficiency and a need for zinc
supplementation."
The form of zinc in Zinc
Challenge liquid is zinc sulfate monohydrate, which is a known
astringent, .i.e., it causes proteins in your mouth to clump, causing a dry
mouth feel (Keast, J Food Sci 2003). It is quite likely that most
people, regardless of their zinc levels, will experience this dry feeling in
their mouth after a short period of time and, if following the suggestions on
the Designs for Health website, may be misled to believe they are zinc
deficient.
Zinc taste tests are
generally not considered to be an accurate measure of zinc status;
some studies that have shown an association between taste test results and
measures of zinc levels in the body have design flaws that make it difficult to
draw conclusions (Gruner, J Altern Complement Med
2012). While it's true that zinc deficiency can cause changes in
taste and/or a decrease in taste acuity (the ability to distinguish between
sweet, salty, sour, etc.) some people are naturally more sensitive to taste
than others, and there are a number of other factors (i.e. age, medications,
medical conditions) that can diminish or alter taste (Schiffman, JAMA 1997).
In fact, the zinc
challenge described above (more formally known as the Bryce-Smith & Simpson
Zinc Taste Test and which is typically performed using two teaspoons,
not tablespoons, of zinc liquid) was also found not to
correlate with self-reported levels of zinc intake according
to a study among 363 young women and men. Only when a different taste scoring
system was used (based on intensity of taste only, not time to taste), a weak
correlation (coefficient of 0.237 out of 1.0) with zinc intake was found for
men, but still not for women. The researchers wrote that the data "does
not support the notion that zinc sulfate taste acuity is a means of how to test
for zinc deficiency." (Zdilla, Clin Nutr ESPEN 11
2016).
Zinc carnosine:
A form of zinc known as zinc carnosine (also called polaprezinc)
— which is a complex of zinc and carnosine (a peptide found in meat and fish) —
is promoted for the treatment or prevention of a variety of gastrointestinal
disorders. Although commonly prescribed in Japan for some of these conditions,
including stomach ulcers and taste disorders, there is limited evidence
supporting its use for any application. To learn more about the outcomes of scientific
and clinical studies done with this form of zinc, see our article about zinc carnosine.
Concerns and Cautions:
·
Zinc supplements cause few immediate side effects other than
occasional stomach upset or unpleasant taste.
·
The established upper tolerable intake levels (ULs) for
daily zinc intake (amounts that should be safe when taken long term by almost
anyone who is in good health) for zinc are: 7 mg for children ages 1 to 3, 12
mg for those 4 to 8, 23 mg for those 9 to 13, 34 mg for those 14 to 18, and 40
mg for individuals 19 years and older.
·
Excessive intake of zinc can interfere with the
absorption of copper, leading to copper deficiency. The combination of
excess zinc and deficient copper can dangerously suppress the immune system and
also cause anemia, heart problems, difficulty with balance and walking, and
changes in mood and cognition. To partially offset these risks, it is generally
considered advisable to take copper at a dose of 1 to 3 mg daily when taking
zinc supplements long term. In some cases,
however, this may not be adequate to prevent copper deficiency, as was reported
in an 81-year-old women taking a vision supplement containing a high daily dose
of zinc (80 mg) and 2 mg of copper (Wahab, J Community Hosp Intern Med Perspect 2021). (See the Vision Supplements Review for more
details.)
Excessive intake of zinc may also exacerbate copper deficiency in people with
underlying conditions. For example, a 62-year-old woman with nutrient
malabsorption due to previous gastric surgery (14 years earlier) was found to
have non-detectable blood levels of copper after taking 50 mg of zinc daily for
one year. She developed copper deficiency-induced anemia, with symptoms such as
muscle pain, fatigue, weakness and lightheadedness that resolved after her
blood levels of copper were increased with copper given intravenously (Tatineni, Clin Case Rep 2020). Prolonged or excessive use of denture adhesives containing
zinc has also been associated with copper deficiency. A hospital in France
reported that four adults (average age 57) developed copper deficiency after
using denture adhesive containing zinc for an average of nine years (Poujois, Intern Med J 2017). However,
copper deficiency can occur within months if using much more
than the recommended amount of adhesive. This was reported in a 67-year-old man
in the UK who developed copper deficiency with symptoms including confusion,
agitation and worsening of memory, as well unsteady gait, spinal and postural
changes ("swayback"), falls and inability to walk unaided seven
months after switching from a zinc-free dental adhesive to a zinc-containing
adhesive (Fixodent) and increasing usage to one tube (70 grams — about 2.4 oz.)
per week instead of the recommended one tube every seven to eight weeks. His
symptoms significantly improved four months after stopping use of the adhesive
and treatment with intravenous and then oral supplementation with copper (Jamal, BMJ Case Rep 2021). The FDA has
received reports of adverse events associated with excessive use of denture
adhesives containing zinc but states they are safe to use in moderation (a
2.4-ounce tube used for upper and lower dentures should last 7- 8 weeks).
·
As noted earlier, when using zinc lozenges for
the treatment of the common cold, one is taking zinc at doses exceeding the UL.
Such short-term use should be safe, but should be limited to no more than one
week. Doses exceeding the UL for more than a week or two should only be used
under physician supervision.
·
Long-term zinc supplementation at very high doses (over 100 mg
per day) has been associated with a decrease in HDL ("good")
cholesterol, reduced immune function, and an increased risk of prostate cancer.
Zinc's overall role in prostate cancer, however, is unclear as there is also
research indicating that zinc may suppress prostate cancer cell growth.
·
Regular use of sunscreens containing zinc as zinc oxide nanoparticles
is unlikely to significantly increase zinc levels or cause toxicity.
A study among 20 people found that applying a zinc oxide sunscreen (~20% zinc
oxide) twice daily for 5 days only increased the normal ~12,000 micrograms of
zinc in the blood by 15.8 micrograms — i.e., there was virtually no increase (Gulson, Toxicol Sci 2010).
·
Zinc nasal gel has been linked in reports to permanent
or temporary loss of smell, as well as pain in the nose immediately after
use. This has been known for several years. By June 2009, a sufficient number
of cases (over 130) had been reported to apparently cause the FDA to issue
a warning to
consumers and health care professionals to discontinue use of three Zicam Nasal
Gel/Nasal Swab products.
·
High doses of zinc or other minerals (calcium, magnesium, and
ferrous iron) from supplements may decrease the absorption of carotenoids, such
as beta-carotene, lycopene and astaxanthin, from foods
and/or supplements. This is likely due to a reaction between carotenoids and
the divalent ions of minerals, making the carotenoids less bioavailable certain forms of iron (Borel, Br J Nutr 2017; Corte-Real, Food Chem 2016). It is
best to take carotenoid supplements at a different time of day than a
supplement or meal containing large amounts of a mineral.
·
Zinc can impair the absorption of antibiotics in
the tetracycline or fluoroquinolone families (e.g., doxycycline, tetracycline,
ciprofloxacin, Cipro, Noroxin), as well as the drug
penicillamine. In addition, combined use of zinc supplements and the drug
amiloride might lead to excess zinc in the body.
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.
Latest Clinical Research Updates for Zinc Supplements and
Lozenges
7/27/2021
Getting too much zinc can
cause neurologic symptoms, and this can occur even with zinc-containing dental
adhesives. Learn more, including the symptoms, in the Concerns and Cautions section of our Zinc
Supplements & Lozenges Review.
11/04/2020
Zinc deficiency can cause
a wide range of problems involving the skin, hair, mouth, and immune system. A
recent report showed that it can also cause an eczema-like rash. Get the
details and learn about the symptoms of zinc deficiency in the What It Is section
of our Zinc Supplements and Lozenges Review. Also see our Top Picks for zinc
supplements and lozenges.
10/13/2020
A recent study found low
blood levels of zinc to be associated with a greater chance of severe symptoms
and death in COVID-19 patients. Does this mean that people should supplement
with zinc or use zinc lozenges? Find out in the COVID-19 section of
our Zinc Supplements and Lozenges Review. Also see our Top Picks for zinc supplements and lozenges.
Zinc for Lowering Blood Sugar and Cholesterol?
8/18/2020
Zinc may help lower blood
sugar as well as cholesterol levels, according to a recent analysis, but the
dose and duration of zinc supplementation made a big difference. Get the
details in the What It Does section
of the Zinc Supplements and Lozenges Review. Also see our Top Picks for
zinc.
6/14/2020
Several individuals
diagnosed with COVID-19 began using zinc lozenges after they became sick. Find
out if this was reported to help or not in the COVID-19 section of
the Zinc Supplements Review. Also see our Top Picks for zinc supplements and lozenges.
Related CL Answers (32)