St. John's Wort Supplements Review

Find the Best St. John's Wort Supplement. Only 40% of St. John's Wort Supplements Pass Tests & Strength Varies Widely.

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

Initially Posted: 09/23/2016

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Table of Contents

Summary

· Do St. John's wort supplements help? Taking a supplement with the right type and amount of St. John's wort extract appears to be as effective in treating major depression of mild to moderate severity as standard antidepressant drugs, but with fewer side effects. St. John's wort is unlikely to help people who aren't truly depressed. (See What It Does)

· How much St. John's wort should I take? Clinical trials suggest that an effective dose is 900 mg per day of a concentrated extract standardized to at least 0.3% hypericin and/or 1% to 3% hyperforin (see ConsumerTips™).

· Which St. John's wort product is best? Choose carefully, because 60% of the St. John's wort supplements selected for testing by ConsumerLab.com did not contain expected amounts of one or more key plant chemicals. There was enormous range in these amounts, indicating that you could get, for example, as much as 280 times more hyperforin from one product than from another. Four products were Approved by ConsumerLab.com, three of which are good choices and one of which was CL's Top Pick. Use our Results Table to see which products were, or were not, Approved, and to compare ingredients, test results, and prices.

· Don't get hurt! Safety and side effects of St. John's wort: Although generally safe, St. John's wort can cause a range of side effects. It may cause mania in people with bipolar disorder and it may increase sensitivity to ultraviolet light, causing unexpected sunburn. Most importantly, St. John's wort can interact with a wide range of medications. See Concerns and Cautions for more information.

What It Is:

The parts of the St. John's wort plant (Hypericum perforatum) used medically include the aerial parts, i.e., those above ground -- the flower, leaves, and stem. St. John's wort contains at least seven constituents or groups of components that may contribute to its biological effects, including naphthodianthrons (e.g., hypericins), flavonoids (e.g., quercetin), bioflavonoids (e.g., biapigenin), xanthons, and phloroglucinol derivatives (e.g., hyperforin) (Nahrstedt 1997).

What It Does:

The vast majority of double-blind, placebo-controlled studies have found that St. John's wort extracts are as effective as standard antidepressant drugs (including antidepressants in the SSRI (Prozac) family) for treating major depression of mild to moderate severity -- and with significantly fewer side effects (Linde 2008; Szegedi, BMJ 2005). This level of depression does not refer to mere "blues" or "moodiness" but a more serious level of depression. However, for severe major depression (often requiring hospitalization), standard antidepressants are thought to be more effective than St. John's wort.

Nevertheless, three well-publicized human studies found no benefit with St. John's wort, although two of these studies found the antidepressant to which St. John's wort was compared wasalso ineffective for treating depression (Hypericum Depression Trial Study Group 2002; Shelton, JAMA 2001). These seemingly paradoxical clinical results may have been due to factors such as the products tested, the outcomes being measured, and the number of people involved in the studies.

St. John's wort does not cause euphoria and, like regular antidepressants, is unlikely to elevate mood in people who aren't truly depressed.

One study involving menopausal women with depression found that a combination of St. John's wort and black cohosh extracts improved both menopause symptoms and mood (Uebelhack, Obstet Gynecol 2006). St. John's wort is also sometimes tried for other conditions in which standard antidepressants might be recommended, such as anxiety, attention deficit disorder, PMS, seasonal affective disorder (SAD), chronic pain, insomnia, neuropathic pain, obsessive compulsive disorder, social phobia, and quitting smoking, but there is no reliable evidence as yet that it really works for these purposes.

For a while, St. John's wort was popular as a treatment for HIV infection. However, current evidence suggests that not only does it not help, but the herb can seriously impair the effect of standard HIV treatments. Even when used for depression, St. John's wort presents some significant safety risks, especially drug interactions. (See Concerns and Cautions).

Hyperforin and Hypericin: Active Ingredients?
Virtually all studies of St. John's wort have used extracts rather than whole herb and the content of most St. John's wort products are standardized to a substance called hypericin, one of the many chemical constituents noted above. Hypericin may not be the most important constituent, but products with standardized hypericin content of about 0.3% have proven to be effective in human studies.

Some other St. John's wort products are standardized to their hyperforin content, which has been shown to be a major antidepressant component of the plant (Zanoli, CNS Drug Rev 2004). Most of the early research on St. John's wort focused on hypericin and hyperforin, though newer studies suggest that the benefit of St. John's wort is based on synergistic interactions of multiple compounds present in the plant and not on the pharmacological activity of any one single compound (Butterweck, Wien Med Wochenschr 2007; Reichling, Forsch Komp Klass Natr 2003). (See ConsumerTips™ for dosage information).

Quality Concerns and Tests Performed:

During the growing season, St. John's wort may accumulate heavy metals from its environment. These include cadmium, a carcinogen and kidney toxin, and lead, which can impair mental functioning and may affect blood pressure. Although the levels of cadmium and lead in a supplement would be small and unlikely to cause disease on their own, the safety margin between exposure in the normal diet and the levels that can produce deleterious effects is relatively small. Therefore, choosing a product with low cadmium and lead levels is best. In 2010, ConsumerLab.com found that four products exceeded strict cadmium limits, with amounts ranging from 0.18 to 0.86 mcg per gram of St. John's wort; one of these products was also contaminated with lead, at 2.2 mcg per daily serving. In addition, three products contained only 23% to 36% of the expected amounts of hyperforin or hypericin. However, among 10 products selected for testing by ConsumerLab.com in 2013, contamination was not found and all products contained the expected phytochemicals. Only one product failed to pass the review and this was because its tablets failed to properly disintegrate in water. No government agency is responsible for routinely testing St. John' wort supplements for their purity and contents. ConsumerLab.com independently evaluated several St. John's wort products to determine whether they contained the St. John's wort amount stated on their labels (based on listed or minimum expected amounts of hypericin and/or hyperforin), disintegrated properly, and did not contain significant amounts of arsenic, cadmium and lead. (See How Products Were Evaluated for information on testing methods and passing score.)

What CL Found:

Among the 10 products ConsumerLab.com selected for testing, 60% failed to meet quality standards as they did not contain listed or minimum expected amounts of hypericin. One of these products was also short on hyperforin. The chemical strength of St. John's wort supplements ranged by a shocking degree across the tested products. Looking at the maximum listed daily serving of each product, the amount of hypericin found ranged from as little as 0.11 mg in Swanson St. John's Wort and The Vitamin Shoppe St. John's Wort Extract to as much as 2.6 mg in Standard Process MediHerb St. John's Wort. There was even greater variation in amounts of hyperforin, which may play a particularly important role in treating depression. Amounts of hyperforin ranged from as little as 0.13 mg in Swanson St. John's Wort to as much as 36.4 mg in Shaklee MoodLift Complex. This means you could be getting 280 times as much hyperforin from one St. John's Wort supplement than from another.

The following products were Not Approved for the following reasons:

· NOW® St. John's Wort contained only 45% of its listed amount of hypericin, which should have been 0.3% of its extract, but was discovered to be only 0.14%

· Planetary Herbals Full Spectrum St. John's Wort Extract was, like NOW, low in hypericin. It did not claim a specific amount of hypericin so was held to the minimum standard of 0.3% but had only 0.13%

· Swanson St. John's Wort, which contains herb powder rather than an extract, failed to provide the USP minimums for St. John's wort herb, providing only 73% of the expected hypericin and just 6% of the expected hyperforin

· Vitacost St. John's Wort Extract, like NOW and Planetary Herbals, provided only 13.6% of the expected minimum amount of hypericin in its extract.

· The Vitamin Shoppe St. John's Wort Extract contained only 4% of its listed amount of hypericin.

· Whole Foods St. John's Wort, which lists a combination of extract and herb, contained only about half the minimum amount of hypericin one would expect from its listed ingredients.

Possibly explaining the high percentage of products which failed to contain expected amounts of hypericin is that the manufacturers of these products may have relied on outdated methods for analyzing St. John's wort. One such method, known as UV-VIS, detects the amount of red color in a sample and is used because hypericin is red. However, it was recently reported some St. John's wort products on the market were adulterated with red dyes to make them appear to contain more hypericin (and, thus, more St. John's wort) than they do in actuality (Frommenwiler, J AOAC Int 2016). In 2006 the United States Pharmacopoeia adopted an improved testing method utilizing high performance liquid chromatography (HPLC). A modified version of this method was later adopted by the Association of Analytical Communities (AOAC) international in 2013 which specifically identifies the hypericin molecule and is not "tricked" by dyes. This HPLC methodology was used by ConsumerLab.com to analyze the products in the current Review, although CL had used the UV-VIS method in earlier Reviews.

Top Pick:

The four St. John's wort supplements which passed testing are shown as "Approved" in the table below, but are somewhat different from one another. Our Top Pick is Standard Process MediHerb St. John's Wort, a concentrated extract similar to St. John's wort products shown to work in clinical studies. It provides the expected concentration of hypericin for an extract (about 0.3%) as well as a substantial amount of hyperforin (23 mg in 3 tablets) -- which may be important to efficacy. The label suggests taking 600 mg to 900 mg daily (2 to 3 tablets), although most studies have used the higher dose — which will cost you $1.13 per day. 

A similar but less expensive extract is Nature's Way Perika, which contains a form of St. John's wort extract called WS 5570 which, as mentioned earlier, has been found to be as effective as the drug paroxetine in treating depression in a six-week study (Szegedi, BMJ 2005). That study started by giving patients the dosage suggested on the Perika bottle — 3 tablets per day, equaling 900 mg of extract. However, that dose was then doubled for more than half the patients in the study who, after two weeks, had not experienced improvement. Doubling the dose seemed to help many of them. It must also be noted that WS 5570 is described in the study as "3% to 6%" hyperforin, while the current product claims a minimum of "2%" hyperforin (we found 2.7%) and when we last tested this product in 2013, the label claimed a minimum of 3% -- so it seems that the current product is of somewhat lower strength than in the past. If it were not for the apparent changes in the formula, Nature's Way Perika would have been our Top Pick because at 52 cents per 3 tablets, it's less than half the price of Standard Process.

Shaklee MoodLift Complex was also Approved due to its high amount of hyperforin (36.4 mg in its upper suggested serving size of 4 capsules daily, costing $1.19), despite providing somewhat less hypericin than claimed — 2 mg instead of 2.7 mg. A 4 capsule serving of Shaklee Moodlift Complex also contains inositol (1 gram) and a "blend" of Eleutherococcus senticosus and green oat extract (200 mg). While there is some preliminary evidence that inositol may be helpful for depression (as well as anxiety and panic disorder) clinical studies have used much higher doses (about 12 grams per day), so the amount of inositol in this product in unlikely to be effective for depression (Mukai, Hum Psychopharmacol 2014; Palatnik, J Clin Psychopharmacol 2001). Eleutherococcus senticosus and green oat extract have both been promoted for "calming nerves" or reducing stress, however, there is very little evidence to support these uses, and the exact amounts of each are not listed. In addition, as a general rule, it's best to use a single ingredient supplement whenever possible to determine what works for you and if a particular ingredient causes side effects.

The one Approved product which is not a concentrated extract is Gaia Herbs St. John's Wort Flower Buds & Tops. While the other extracts are about 6:1 or 7:1 concentrations, Gaia is a dilute (1:2) extract but it does contain, just as it claims, the equivalent of 500 mg of St. John's Word herb in each mL of liquid. Its upper suggested daily serving size of 40 drops (1.33 mL), costs $1.36, making it the most expensive product in this review, but provides, for example, just one-third the amount of hypericin (0.85 mg) and half the hyperforin (12.8 mg) found in the Standard Process product.

Test Results by Product:

Below are the test results for 10 St. John's wort products selected for review by ConsumerLab.com, listed in alphabetical order. Shown for each product are the claimed amount and form of St. John's wort, the daily serving size recommended on its label, and the amounts of hypericin and hyperforin found by ConsumerLab.com in a daily serving. Products listed as "Approved" met their label claims and ConsumerLab.com's quality criteria (see How Products Were Evaluated). The full list of ingredients (including special dietary designations) is available for each product by clicking on the word "Ingredients" in the first column. Cost comparisons are shown in the last column, as are other notable features.

RESULTS OF CONSUMERLAB.COM TESTING OF ST. JOHN'S WORT SUPPLEMENTS Click on beneath a product name to find a vendor that sells it. To find retailers that sell some of the listed products click here.
Product Name, Amount of Extract and/or Herb per Serving, Serving Size, and Suggested Daily Serving on Label Click on "Ingredients" for Full Listing	Claimed Amount in Suggested Daily Serving	-- TEST RESULTS -- (See How Products Were Evaluated)				Cost for Daily Suggested Serving on Label [Cost for 900 mg of Extract or Equivalent*] Other Notable Features^3 Price Paid
		OVERALL RESULTS: APPROVED or NOT APPROVED	Contained Claimed or Minimum Expected Amounts of Hypericin and/or Hyperforin Per Suggested Daily Serving Expected Minimums:^1 Hypericin: 0.3% of Extract; 0.04% of Herb Hyperforin: None Established for Extract; 0.6% of Herb	Did Not Exceed Contamination Limits for Lead, Cadmium and Arsenic^2	Disintegrated Properly (NA=Not Applicable)
Gaia® Herbs St. John's Wort Flower Buds & Tops, 500 mg/ml herb equivalency (665 mg herb per 40 drops [1.33 ml], Herb Strength Ratio 1:2; 30-40 drops, three times daily) Dist. by Gala Herbs, Inc. Ingredients	1,500 mg to 2,000 mg herb in a dilute (1:2) extract	APPROVED Note: Lower strength than other Approved products which are concentrated extracts and provide more hypericin and hyperforin per daily serving.	Hypericin found: 0.64 mg to 0.85 mg (0.04% of extract; 106.3% of USP expected minimum for herb) Hyperforin found: 9.6 mg to 12.8 mg (0.64% of extract; 106.7% of expected minimum for herb)	NA	NA	$1.02-$1.36 [$4.60]* $10.43/1 fl. oz. [30 ml] bottle (approx. 23 servings^4)
Nature's Way® Perika® St. John's Wort (300 mg extract per tablet; 1 tablet, three times daily) Dist. by Nature's Way Products, LLC Ingredients	900 mg extract 18 mg (minimum 2%) hyperforin	APPROVED Note: May be lower strength than past formula which claimed a minimum "3%" hyperforin rather than the current "2%"	Hypericin found: 1.3 mg (0.14% of extract; 48.1% of expected USP minimum for extract but acceptable as matches the lower end of the clinically tested formula which was 0.12-0.28% hypericin) Hyperforin found: 23.9 mg (2.7% of extract; this rounds to match the lower end of the clinically tested formula which was 3-6% hyperforin)	NA		$0.52 [$0.52] Contains no wheat and yeast, gluten free $10.39/60 tablets
NOW® St. John's Wort (300 mg extract per veg capsule; 1 veg capsule, three times daily) Dist. by NOW FOODS Ingredients	900 mg extract 2.7 mg (0.3%) hypericin	NOT APPROVED	Hypericin found: 1.2 mg (0.14% of extract; only 45.4% of listed amount) Hyperforin found: 5.7 mg (0.63% of extract)	NA	NA	$0.18 [$0.18] Non-GMO, not manufactured with wheat and gluten $14.70/250 veg capsules
Planetary Herbals® Full Spectrum™ St. John's Wort Extract (600 mg extract per tablet; 1 tablet, twice daily)  Dist. by Planetary Herbals, LLC Ingredients	1,000 mg extract (standardized) 200 mg extract	NOT APPROVED Note: Passed in 2013, when second extract listed as "4:1" but no longer claimed. Less concentrated extract seems to be used currently.	Hypericin found: 1.5 mg (0.13% of extracts; only 41.9% of expected minimum) Hyperforin found: 1.0 mg (0.087% of extracts)	NA		$0.30 [$0.23] Calcium $9.05/60 tablets
Shaklee® MoodLift® Complex (225 mg extract per capsule; 1 to 4 capsules, once daily) Dist. by Shaklee Corporation Ingredients	225 mg to 900 mg extract 0.67 mg to 2.7 mg (0.3%) hypericin	APPROVED	Hypericin found: 0.50 mg to 2.0 mg (0.22% of extract; 73.9% of listed amount)^8 Hyperforin found: 9.1 mg to 36.4 mg (2.63% of extract)	NA	NA	$0.30-$1.19 [$1.19] Inositol, Eleutherococcus senticosus, green oat extract Gluten free $35.65/120 capsules
Standard Process® MediHerb® St. John's Wort 1.8 g (300 mg extract per tablet; 1 tablet, twice to three times daily) Dist. by Standard Process Inc. Ingredients	600 mg to 900 mg extract 1.8 mg to 2.7 mg (0.3%) hypericin	APPROVED	Hypericin found: 1.8 mg to 2.6 mg (0.29% of extract; 97.8% of listed amount) Hyperforin found: 15.8 mg to 23.7 mg (2.6% of extract)	NA		$0.75-$1.13 [$1.13] Calcium $15.00/40 tablets
Swanson® St. John's Wort (375 mg herb per capsule;1 capsule, once daily) Dist. by Swanson Health Products Ingredients	375 mg herb	NOT APPROVED	Hypericin found: 0.11 mg (0.029% of herb; 73.3% of expected minimum for herb) Hyperforin found: 0.13 mg (0.034% of herb; 5.64% of expected minimum for herb)		NA	$0.03 [$0.60]^* $1.99/60 capsules
Vitacost® St. John's Wort Extract (450 mg extract per capsules; 1 capsule, once daily) Dist. by Vitacost Ingredients	450 mg extract 1.35 mg (0.3%) hypericin	NOT APPROVED	Hypericin found: 0.18 mg (only 0.04% of extract; only 13.6% of listed amount) Hyperforin found: 2.5 mg (0.56% of extract)	NA	NA	$0.07 [$0.13] Free of gluten $5.99/90 capsules
The Vitamin Shoppe® St. John's Wort Extract (300 mg extract per veggie capsule;1 veggie capsule, once to three times daily) Dist. by Vitamin Shoppe, Inc. Ingredients	300 mg to 900 mg extract 0.9 mg to 2.7 mg (0.3%) hypericin	NOT APPROVED	Hypericin found: 0.036 mg to 0.11 mg (0.012% of extract; only 4% of listed amount) Hyperforin found: 0.49 mg to 1.5 mg (0.16% of extract)	NA	NA	$0.08-$0.25 [$0.25] Does not contain wheat, gluten and yeast $19.99/240 veggie capsules
Whole Foods St. John's Wort (300 mg extract and 150 mg herb per vegan capsule; 1 vegan capsule, once to twice daily) Dist. by Whole Foods Markets Ingredients	300 mg to 600 mg extract 150 mg to 300 mg herb	NOT APPROVED	Hypericin found: 0.56 mg to 1.1 mg (0.19% of extract; only 58.6% of minimum expected total amount^7) Hyperforin found: 3.4 mg to 6.8 mg (1.1% of extract)		NA	$0.13-0.27 [$0.37]* Kosher, suitable for vegans $7.99/60 vegan capsules
* The cost calculations in the last column are based on claimed amounts of extract and/or equivalent amount of whole herb or liquid extract based on hypericin content. 1 Products containing dried, powdered flowers/tops or aerial parts are expected to contain 0.04% hypericin and 0.6% hyperforin, and products containing an St. John's Wort extract must contain a minimum of 0.3% hypericin unless clinical evidence exists indicating efficacy with amounts found. 2 Only products that contain whole herb(s) and/or more than 250 mg of minerals daily were tested for lead, arsenic and cadmium. 3 Not tested but claimed on label. 4 Based on 40 drops. 5 Calculated using the claimed 0.3% hypericin claimed of the extract plus the minimum of 0.3% hypericin of the second extract. 6 Label states a serving size is "4 capsules", however the directions state "Take 1-4 capsules daily." 7 Calculated using the claimed 0.3% hypericin of the extract and the minimum of 0.04% hypericin of the herb. 8 Despite containing somewhat less hypericin than listed, product was Approved as it provides as much hyperforin and hypericin as found in Perika, which has clinical evidence of efficacy and CL permits up to 33% less hypericin than listed due to increased specificity of HPLC over the historically used method of UV-VIS upon which the 0.3% may have been based.
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, 2016. All rights reserved. Not to be reproduced, excerpted, or cited in any fashion without the express written permission of ConsumerLab.com LLC.

ConsumerTips™:

When buying a St. John's wort supplement, be sure to look at the label to find out if the product is made from an extract or whole herb (i.e., dried, powdered herb). Most of the St. John's wort preparations found effective in human trials were extracts standardized to contain approximately 0.3% hypericin, and taken in a dose of 300 mg three times daily. Other products that have shown benefits were additionally standardized to 1 - 3% hyperforin, again taken at 300 mg three times a day. Whole herb is usually taken at a dose of 2 to 4 grams per day and should contain 0.1% to 0.15% hypericin. Products containing whole herb tend to have higher concentrations of heavy metals than extracts, as some contaminants may be removed during the extraction process. Labels on St. John's wort products should also indicate the parts of the plant used. These should be the flowers and leaves — also referred to as "aerial portions" (which may also include stems) — but not the roots.  As with conventional antidepressants, it appears that St. John's wort takes several weeks to achieve full effects.

Concerns and Cautions:

St. John's wort is generally safe when taken in appropriate amounts, seldom causing more than occasional mild digestive distress. Other reported side effects include anxiety, fatigue, headache, insomnia and skin rashes. Like all antidepressants, St. John's wort can cause manic episodes in people with bipolar disorder, and one long-term study (Sarris, Pharmacopsychiatry 2012) found use of St. John's wort was associated with an increase in anorgasmia (inability to have an orgasm). Use of St. John's wort has also been linked to hair loss in one report (as has use of conventional antidepressants).

An analysis of adverse drug reactions reported in Australia from 2000 to 2013 found reactions for St. John's wort were similar in type to those for fluoxetine, the SSRI drug in the prescription medication Prozac. Most were mild to moderate, including such as events nausea, diarrhea, headache, fatigue, ear pain and chest pain; anxiety, panic attacks, dizziness, vomiting, amnesia and aggression were also reported. The number of reported events was greater for fluoxetine than for St. John's wort (447 vs. 84, respectively) although the researchers note that use of fluoxetine is estimated to be about double that for St. John's wort and they speculate that adverse reactions are more likely to be reported for drugs than for dietary supplements. (Hoban, Clin Exp Pharmacol Physiol 2015). The analysis found that serious adverse events were more likely to occur when the herb was taken with certain medications; for example, a case of life-threatening serotonin syndrome occurred when St. John's wort was taken with the SSRI anti-depressant sertraline (Zoloft). (See chart below for more about potential drug interactions).

Avoid abruptly stopping St. John's wort, which can lead to unpleasant withdrawal symptoms (headache, nausea, insomnia, fatigue, and others).

A few case studies and reports with immune compromised patients suggest that high doses of St. John's wort may increase sensitivity to ultraviolet light (the part of sunlight that causes sunburn). Studies conducted with healthy subjects and normal doses of St. John's wort did not show this problem, though some people could be unusually sensitive (Hammerness, Psychosomatics 2003). Furthermore, there are individual reports of unexpected sunburn in people receiving medical ultraviolet treatment who were taking St. John's wort at normal doses. Perhaps related to St. John's ability to increase sensitivity to ultraviolet light is an anecdotal, self-reported population survey suggesting an association between the use of St. John's wort and cataract development (Booth, Curr Eye Res 2009).

For these reasons, it is not recommended to get a high level of sun or ultraviolet exposure while using St. John's wort. Amplification of this effect by drugs (such as sulfa antibiotics) that can increase sun sensitivity could be a possibility as well.

A study using DNA analysis of herbal products reported that one St. Johns wort product (name not identified) actually contained the herb senna (a laxative) instead of St. John's wort, and noted that many herbal products contain unlisted ingredients (Newmaster, BMC Med 2013).

Finally, there is a little evidence that excessive doses of St. John's wort might slightly impair mental function, and one report that the herb appeared to cause severe worsening of symptoms of Alzheimer's disease.

The most significant risk with St. John's wort involves drug interactions. It appears that St. John's wort may reduce blood levels of many medications, thus reducing their effectiveness. This interaction might occur with as many as half of all the drugs in use today. Some of the strongest and most worrisome evidence involves the following medications:

Drugs Which May Have Reduced Effectiveness When Used with St. John's Wort
Drug:	Possible harmful effect of combination with St. John's wort:
Cyclosporine or tacrolimus, used to suppress transplant rejection	Transplant rejection
Oral Contraceptives; Estrogen replacement	Unintended pregnancy; Decreased levels of hormone replacement drugs
Protease inhibitors and non-nucleoside reverse transcriptase inhibitors used for HIV infection	Worsening of HIV symptoms
Nucleotide analog polymerase inhibitors (e.g., sofosbuvir in Sovaldi and Harvoni) and NS5A inhibitors (e.g., ledipasvir found in Harvoni), drugs to cure hepatitis C infection	Decreased plasma concentration of drug and reduced therapeutic effect
Digoxin, a treatment for various forms of heart disease	Increased heart disease symptoms
Statin drugs, taken to improve cholesterol levels	Higher levels of cholesterol
Warfarin (coumadin), a blood thinner used to prevent blood clots	Failure of protection against blood clots
Various cancer chemotherapy drugs	Loss of efficacy against cancer
Anti-psychotic drugs in the olanzapine and clozapine category	Increased symptoms of psychosis
Omeprazole (Prilosec) and related drugs	Increased ulcer or esophageal reflux symptoms

St. John's wort may also speed the metabolism of medications for erectile dysfunction, such as sildenafil (Viagra) and tadalafil (Cialis), thereby reducing their effectiveness (Henderson, B J Clin Pharmacol 2002; Markowitz, JAMA 2003).

Be aware that suddenly stopping St. John's wort while on one of these medications can also have adverse effects due to a kind of reverse-risk. If you are taking St. John's wort, and your physician adjusts your medication levels to get the proper blood levels, and you then stop taking the herb, blood levels of your medication canrise suddenly,causing toxic side effects.

Besides reducing blood levels of medications, St. John's wort can cause other problems if taken in combination with certain drugs. Some of the most important of these miscellaneous interactions include:

Other Drugs Impacted by St. John's Wort
Drug:	Possible harmful effect of combination with St. John's wort:
Conventional antidepressants, especially those in the SSRI family (such as Celexa, Prozac and Zoloft), but also possibly other antidepressants, as well as anti-migraine drugs and the painkiller tramadol	Excessive serotonin levels, leading to "serotonin syndrome," a condition that includes one or more of the following symptoms: nausea, anxiety, mental confusion, fever, tremor, seizures, altered heart rate, unstable blood pressure, and even death.
Anesthetics	Delayed emergence from anesthesia after surgery
Drugs that can cause sun sensitivity (especially the anti-inflammatory medication piroxicam and sulfa antibiotics)	Increased sun sensitivity
MAO inhibitors, stimulant drugs, and the substance tyramine (found in aged cheese, wine, fermented soy products, cured meats, and beer)	MAOI interaction, consisting of rapid heart rate, high blood pressure and sometimes delirium

NOTE: While the above discussion may make it seem that St. John's wort is an unusually dangerous herb, it is probably more accurate to say that it is an especially well studied herb, and its risks are better known. For example, grapefruit juice causes many of the same drug interactions described above, and it is not ordinarily considered a dangerous substance!

Because of all these actions and interactions, individuals should discuss using St. John's wort with their physician before taking it.

The safety of St. John's wort hasn't been well evaluated in children or during pregnancy or breast-feeding. It is recommended that St. John's wort be avoided by women who are or may become pregnant or who are breastfeeding.

To further assist consumers, ConsumerLab.com licenses its flask-shaped CL Seal of Approved Quality (see The CL Seal) to manufacturers for use on labels of products that have passed its testing. ConsumerLab.com will periodically re-evaluate these products to ensure their compliance with ConsumerLab.com's standards.

Information on this site is provided for informational purposes only. It is not an endorsement of any product nor it 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.

Latest Clinical Research Updates for St. John's Wort Supplements

Adverse Reactions with St. John's Wort

8/05/2015

A recent analysis found adverse reactions associated with St. John's wort were similar to those reported for the prescription SSRI antidepressant fluoxetine (Prozac), and serious adverse reactions were most likely to occur when the herb was taken in addition to a prescription drug. Get the details, plus more about concerns and potential drug interactions and our tests of popular supplements in the St. John's wort Supplements Review >>

Caution with St. John's Wort

10/10/2014

St. John's wort is known to interact with a large number of prescription drugs. That number grew larger recently when the FDA approved two new drugs to cure hepatitis C infection. Taking these drugs while using St. John's wort may lead to reduced therapeutic effect and is not recommended. More information about this and other drug interactions with St. John's wort is found in the "Concerns and Cautions" section of the St. John's Wort Supplements Review >>

Most Herbal Products Don't Contain Listed Herb

10/13/2013

DNA analysis of 44 herbal products from Canada and the U.S. found that only 48% contained the herb listed on the label and one-third of these products contained contaminants or fillers not listed on the label (Newmaster, BMC Med 2013). Nine percent of products contained only rice or wheat and none of the listed herb. Many cases of herb substitution were reported, including senna (a laxative) in a product labeled as St. John's wort. Several products were contaminated with feverfew, which should not be consumed by pregnant women and may react with a variety of medications. The researchers, from the University of Guelph in Ontario, did not disclose the identities of the tested products, which were single-ingredient herbs sold as capsules, powders, or tablets. Significant challenges continue to exist for routine use of DNA analysis of herbs, but ConsumerLab.com may use this technique where appropriate in the future, alongside other analytical techniques in its Product Reviews.   

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