Ashwagandha Supplements Review by ConsumerLab.com

Product Review: Ashwagandha Supplements

Initial Posting: 12/20/14 Last Update: 5/3/17 Ashwagandha supplements. Reviewed by ConsumerLab.com

Sections: Jump to a section by clicking on its name.

What It Is
What It Does
Quality Concerns and What CL Tested For
What CL Found
Test Results by Product
What to Consider When Buying and Using
Concerns and Cautions
Full list of Ingredients by Product
How Products Were Evaluated

Summary: What You Need to Know About Ashwagandha Supplements

Preliminary studies suggest that ashwagandha may help reduce anxiety, improve physical and cognitive performance, and have other benefits. However, larger studies are needed for confirmation.
When choosing an ashwagandha product, look for a root powder or a root extract containing, respectively, at least 0.3% and 1.5% of withanolides — key marker compounds which may also play a role in the herb's activity.
Daily dosage for a root powder is typically 1 to 6 grams (1,000 to 6,000 mg). For extracts it is 500 to 1,500 mg. The daily dose should provide at least 6 mg withanolides — typically between 10 and 30 mg in most studies.
The majority of products selected for review failed to be approved. Only 3 three products in the current review were Approved by ConsumerLab.com, providing a reasonable daily dose and accurate labeling:
- Plnt by V Ashwagandha (The Vitamin Shoppe)
- Pure Encapsulations Ashwagandha
- Solaray Ashwagandha
Among these, Pure Encapsulations Ashwagandha appears to offer the best value. The recommended dose is 1 capsule per day, costing 28 cents and providing 12.5 mg of withanolides from 500 mg of root extract.
Although ashwagandha is generally well tolerated, larger doses can cause side effects and certain people should use it with caution

What It Is:
Ashwagandha (Withania somnifera) is an herb grown in India and in certain regions of Nepal. The roots contain withanolides, which are compounds thought to be responsible for some of the herb's effects (Prabhakaran, Pak J Pharm Sci 2012). Ashwagandha is sometimes referred to as "Indian ginseng" because it is thought to have similar "adaptogen" qualities, such as modulating the immune system and supporting the body's response to stress. It is also sometimes referred to as "winter cherry," but should not be confused with another plant, Physalis alkekengi, which is also commonly referred to as "winter cherry."

What It Does:
A number of small, short-term studies suggest a variety of potential uses for ashwagandha, but larger, long-term studies are needed to confirm these findings.

Anxiety/Insomnia
Clinical studies suggest that ashwagandha can reduce anxiety and stress. One randomized, double-blind study of 75 middle-aged adults with moderate to severe anxiety found that anxiety was dramatically reduced, and fatigue, motivation and concentration significantly improved, in those who received 300 mg of ashwagandha root extract (standardized to 1.5% withanolides) twice per day (a total daily dose of 600 mg ashwagandha extract containing 9 mg of withanolides), plus a daily multivitamin for 12 weeks (Cooley, PLOS One 2009). A second group of patients in the study who, instead, received a weekly psychotherapy sessions and a placebo, had a smaller reduction in anxiety. Both groups were encouraged to reduce their intake of stimulants (caffeine, chocolate, tobacco, etc.) and were instructed in deep-breathing exercises.

A small study among people with generalized anxiety disorder, panic disorder, and anxiety mixed with depression, found that those who took ashwagandha extract (two to six 250 mg tablets per day, for a total daily dose of 500 to 3,000 mg — amounts of withanolides not specified) for 6 weeks had significant improvement compared to those taking a placebo (Andrade, Indian J Psychiatry 2000).

Ashwagandha has been used and promoted for the treatment of insomnia, and even part of its scientific name — somnifera — refers to "sleep." Nevertheless, there are only animal experiments suggesting this effect and no clinical studies in people. However, as insomnia is often due to stress and anxiety, and ashwagandha may reduce these states, a beneficial effect on insomnia is certainly possible — but not proven.

Male infertility
A placebo-controlled clinical study in men with low sperm count found one capsule of ashwagandha extract taken three times daily (a total daily dose of 675 mg extract, 33.75 mg withanolides) increased sperm concentration, volume and motility by, respectively, 167%, 53% and 57% over 3 months. Compared to men who took a placebo, men who took the ashwagandha also had a significant increase in serum testosterone levels (Ambiye, Evid Based Complement Alterat Med 2013).

Sexual function in women
A 2-month study in 50 women ages 21 to 50 in India with low sexual desire and/or arousal found those who took 300 mg of ashwagandha extract after eating, twice per day, had significant improvements in overall sexual function, including arousal, lubrication, and satisfaction compared to placebo; although there was not a significant improvement in sexual desire. No adverse effects were observed (Dongre Biomed Res Int 2015). The researcher's theorized that ashwagandha may improve sexual function in women by reducing stress and potentially increasing testosterone levels (as has been shown in men), although this was not measured in the study. (The extract used was KSM-66 from Ixoreal Biomed, containing 5% withanolides, which is about 2 to 3 times as concentrated as the products in this Review. It is available, however, in products such as Swanson Ultimate Ashwagandha KSM-66, and ProHealth Optimized Ashwagandha KSM-66, although these have not been tested by ConsumerLab.com).

Cognitive performance
Small but well-controlled studies in India have shown ashwagandha to improve cognitive performance in adults. A study among healthy men found that taking two 250 mg capsules of ashwagandha extract with a glass of water each morning and evening (providing a total daily dose of 1,000 mg ashwagandha extract [SENSORIL, Natreon, USA] with at least 100 mg of withanolides) for 12 days significantly improved cognitive performance and reaction times compared to placebo (Pingali, Pharmacognosy Res 2014). A study among men and women with mild cognitive impairment (average age of 50) found that taking 300 mg of ashwagandha root extract (KSM-66 from Ixoreal Biomed, USA) twice daily (providing a total daily dose of 600 mg containing 30 mg of withanolides) for 8 weeks significantly improved many aspects of immediate and general memory, executive function, sustained attention, and information processing speed compared to placebo (which showed lesser improvements). Most improvements were not significant relative to placebo after 4 weeks and required 8 weeks. There was no significant effect on visuospatial processing, i.e., drawing images from memory and comparing rotated images (Choudhary, J Diet Supp, 2017).

Physical performance
A small study in healthy men and women ages 18 to 25 found that a daily dose of 500 mg of ashwagandha root extract (% withanolides not listed) taken one hour after a meal for 2 months significantly improved measures of physical performance and cardiovascular endurance, including velocity while sprinting, leg muscle strength, and VO₂Max (a measure of aerobic capacity) compared to placebo (Sandhu, Int J Ayurveda Res, 2010).

Anti-inflammatory
Ashwagandha may have anti-inflammatory and analgesic properties. This was demonstrated in a small but well-controlled study in India of an extract made from ashwagandha leaves as well as roots (Sensoril®, Natreon, New Jersey) having a particularly high concentration of withanolides (not less than 10%). In the study, people with joint pain and discomfort from knee osteoarthritis took capsules containing 250 mg of extract, 150 mg of extract, or a placebo twice a day for 12 weeks. Significant reductions were observed on measures of pain, stiffness, and disability at both doses, although the 250 mg group showed earliest efficacy — at just 4 weeks. There were no adverse effects reported and no one dropped out of the study, although side effects were most common in the 250 mg group -- 20% of whom reported nausea. (Ramakanth, J Aruv Integ Med 2016) [Note: Sensoril is now found in several brands of supplements but was not an ingredient in products tested for this Review. The higher dose (250 mg) of extract used in this study would provide at least 50 mg of withanolides, which is much more than expected from the suggested serving sizes of products in this Review.]

Another clinical study found that two capsules (each containing 450 mg of ashwagandha root, 50 mg zinc complex, 100 mg of guggul and 50 mg of turmeric) taken 3 times daily for three months significantly reduced pain among patients with osteoarthritis, but no improvements were seen on x-ray (Kulkarni, J Ethnopharmacol 1991). Because the product contained a number of ingredients, it's not possible to know what the effect of ashwagandha alone might have been.

Quality Concerns and What CL Tested for:
Neither the Food and Drug Administration (FDA) nor any other federal or state agency routinely tests supplements for quality prior to sale. In order to help consumers identify products of better quality, ConsumerLab.com purchased and tested ashwagandha supplements to determine whether they contained the labeled and expected amounts of withanolides and withanosides (referred to collectively in this report as withanolides) and did not exceed contamination limits for lead, cadmium and arsenic. All products in regular tablet/caplet form also underwent disintegration testing to check if they would break apart properly in solution. ConsumerLab.com also determined whether the label recommended dose provided at least 6 mg of withanolides.

See How Products Were Evaluated for more information on testing.

Update:

(1/23/15): ConsumerLab.com was contacted by a representative of the distributor of one of the products which failed to pass this review for not meeting expectations applied by CL. CL acknowledges that it mistook the product for being a concentrated extract when information on its label indicated it to be a more dilute extract. CL has corrected the information in the report about this product, indicating that it does meet the expectations of its label, although it still does not pass the review as it does not provide the minimum expected total daily amount of withanolides generally shown to be effective in clincal trials. CL recognizes that it made a similar error with regard to a second extract and has corrected this information as well. That product also continues to not meet expectations applied by CL, as it provides a lower dose than expected from its label and a low daily dose.

(12/23/14): ConsumerLab.com was contacted by the distributor of one of the products which failed to pass this review. The distributor claims that the product should not have been held to the expectations applied by CL. However, CL believes that it properly interpreted the product labeling and applied appropriate expectations. More details are available in the Update in the full review.

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