Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to ashwagandha supplementation.
Ashwagandha is one of the most popular herbal supplements, and for good reason. There’s extensive clinical research backing its efficacy for stress reduction, and some studies suggest the herb may also be effective for improving testosterone levels and fertility in men.
But which ashwagandha brands use an effective dose and format similar to that in medical studies? Are any ashwagandha brands contaminated? What is KSM-66 ashwagandha, and is it really more effective? And how can consumers determine if an ashwagandha supplement is worth the money?
In this article we'll answer all of these questions and more, and hopefully help readers make sense of the thousands of brands selling ashwagandha supplements in various formats and doses.
We'll explain how to qualify ashwagandha supplements based on their form and dosage, explain what KSM-66 ashwagandha is and if it's more effective than regular ashwgandha, and discuss whether some popular ashwagandha brands have been shown to be contaminated in third-party tests.
We'll also provide our two top ashwagandha picks based on third-party test results and formulation.
What to Look For in an Ashwagandha Brand
Dosage is one of the most important things to consider when choosing an ashwagandha supplement. You want to choose a brand that uses a dose shown to be effective in clinical studies.
A medical review on ashwagandha published in the Journal of Alternative and Complementary Medicine highlighted three studies on ashwagandha.
The doses used in the three studies were 600, 600 and 1,000 milligrams (mg) per day.
We consider around 600 mg to be an effective ashwagandha dose.
Format is the second consideration. Ashwagandha is available in many forms, but most of the clinical studies we've reviewed use either ashwagandha extract (which is a more concentrated form of the herb), or ashwagandha root powder (which is the unprocessed form of the herb).
Both forms have been shown to be effective in clinical trials, but we've come across significantly more clinical trials using ashwagandha extract than raw ashwagandha powder, which suggests that ashwagandha extract is the medical standard.
Standardization is the third consideration, although it's less important than the first two.
Standardization refers to the process of ensuring a minimum quantity of the active chemical compound in the plant through concentration.
In the case of ashwagandha, supplements are often standardized for withanolides, which is a phytonutrient in ashwagandha thought to be responsible for many of its positive effects.
We don’t have a preference between generic (non-standardized) ashwagandha extract and standardized ashwagandha. There are many studies proving both to be effective.
In summary, it seems from a review of clinical research that ashwagandha extract supplements providing a dosage of 600 mg per day or above are the most likely to be effective.
Is KSM-66 Ashwagandha More Effective?
Consumers who have considered purchasing an ashwagandha supplement have likely come across something called “KSM-66.”
KSM-66 is a patented ashwagandha extract which is “full-spectrum,” meaning it maintains the same ratio of active chemicals in the extracted version as in the dry herb.
The company which manufactures it, called Ixoreal Biomed, also claims to use no leaves in the formulation; only ashwagandha root.
We haven’t come across any clinical research suggesting that KSM-66 is more effective than non-patented ashwagandha extract.
There are many clinical trials suggesting KSM-66 ashwagandha is effective, and also many clinical trials suggesting that non-branded ashwagandha is effective.
We don't currently believe it's worth paying a premium for KSM-66 ashwagandha.
Is Ashwagandha Contaminated?
We recommend that consumers exercise caution when purchasing ashwagandha supplements, due to the unique potential for the plant to absorb toxic heavy metals from soil.
A 2010 medical review on heavy metal accumulation in various medicinal plants found ashwagandha to show “very high metal bioaccumulation.”
The levels of heavy metals absorbed by ashwagandha were significantly higher than all other plants examined.
This doesn't mean that all ashwagandha supplements are contaminated; it just highlights the importance of choosing a reputable brand, because a low-quality ashwagandha brand may expose consumers to levels of heavy metals above safe thresholds.
One way to check the contaminant levels for different ashwagandha brands is to read ConsumerLab's review of ashwagandha supplements.
ConsumerLab is a third-party, independent lab testing company that publishes off-the-shelf test results of popular brands.
Their ashwagandha review, linked above, analyzed 16 different ashwagandha supplements and only 11, or 69%, passed both label accuracy and purity tests.
Our Top Ashwagandha Pick
Organic India Ashwagandha Capsules is the best-priced ashwagandha supplement that passed ConsumerLab testing, costing only $0.36 per serving at the time of updating this article.
This product is a raw powder and will be less potent than an ashwagandha extract.
Organic India's supplement was accurately labeled according to ConsumerLab's test results (meaning it contained the phytonutrients in ashwagandha at the same dose that the brand claims on its label), and did not exceed thresholds for heavy metal contamination.
YouTuber Tries Ashwagandha
One of the most popular YouTube videos on a real user's experience trying ashwagandha comes from a creator named Dalati who took the supplement for a full year straight, and shares his experience in a video with over one million views:
