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Ashwagandha capsules in females hand

Ashwagandha guide: Benefits, dosage, supplements & more

13 Feb 2024 • 8 min read

Ashwagandha has been used for centuries in traditional medicine in India, with praises for its medicinal properties - but what makes it special and is there any science to it?1

Ashwagandha, commonly used in Indian ayurvedic medicine, has traditionally been used to help almost everything, from arthritis to rheumatism. Some use it as a general tonic to increase energy, and improve overall health, while others use it to prevent illness in athletes and the elderly.1

It is worth noting though, that ashwagandha is not recommended for use during pregnancy and lactation, plus if you’re taking medication, you always should consult with a healthcare professional before starting use.

So, what is the evidence to back up these so-called benefits that have been linked to using ashwagandha, or its KSM-66 extract? In this article, you’ll discover everything there is to know.

What is ashwagandha?

Ashwagandha is a small evergreen shrub that originates from parts of India, the Middle East, and Africa.1 Its unusual name relates to the way it smells – ashwagandha roots smell like a horse, with ‘ashva’ meaning ‘horse’ and ‘gandha’ meaning ‘smelling like’ in Sanskrit. The entire plant is harvested, dried, and ground down into a powder, which is sold as ashwagandha supplements.2

The ashwagandha plant has been traditionally renowned by those who believe in Ayurvedic medicine as one of the most powerful herbs, which spans back thousands of years.1

Typically, when people refer to ashwagandha, they are referring to the extract.

What is the difference between KSM-66 and ashwagandha?

The difference between KSM-66 and regular ashwagandha is that traditional ashwagandha is composed of extracts derived from both the leaf and root of the ashwagandha plant, whereas KSM-66 follows a conventional approach and is composed solely of root extract.3

The health benefits of ashwagandha

Ashwagandha has been used for many things over the last 3,000 years.

Potential uses of ashwagandha that have been researched include effects on stress and anxiety, sexual function and fertility, athletic performance, cognitive performance, pain, fatigue, thyroid function, schizophrenia, diabetes, obsessive-compulsive disorder, insomnia, hypercholesterolemia, and tuberculosis. Initial findings for some of these conditions have been promising, but more robust clinical study designs are needed before confirming its benefits.

Our video recap explains all the potential health benefits of ashwagandha, its history, and how to use it.

Benefits of Ashwagandha | Debunking Wellness | H&B

Although ashwagandha has a long list of potential benefits, is there any scientific evidence behind it?

There have been many scientific studies on ashwagandha, many of which, however, have small sample sizes, short duration times, and other limitations. So, further robust studies are needed to confirm these potential benefits.

Nonetheless, some promising findings from the following studies suggest ashwagandha and KSM-66 may help with the following: 
  • May reduce stress – Two studies investigated how ashwagandha might help reduce mild stress, but more research is needed with diverse and larger populations and varying dosages.4,5
  • May reduce anxiety – One 2022 review of ashwagandha studies found that ashwagandha significantly reduced anxiety compared to placebo. While this is promising, the authors acknowledged higher quality studies are needed to establish this potential benefit.
  • May help with fatigue – A scientific study involving 120 participants researched fatigue levels and found that ashwagandha may have ‘anti-fatigue’ effects through its effect on the autonomic nervous system’6
  • May increase testosterone – One study looked into the link between ashwagandha and stress in 60 people, but as an adverse effect actually found that testosterone levels increased in the male participants during the study.5 They didn’t observe the same effects in the female participants.
  • May help with poor memory – Another placebo-controlled study involving 60 participants found that one ashwagandha capsule per day for 90 days improved memory in participants who were stressed.7
  • May improve concentration – Focus can be heavily affected by stress, so based on the findings discussed earlier, we are not surprised that in the same scientific study where they found memory improvement, they found that ashwagandha improved concentration in people who reported high levels of stress.
  • May help with better quality sleep – A 2021 study found that one ashwagandha capsule per day helped improve sleep quality in participants.
  • May help with low libido – Two independent studies both found that ashwagandha helped people involved in their studies have better quality ‘sexual function’.8,9
  • May improve endurance – Anecdotally, ashwagandha is supposed to help with endurance of any kind. Studies into this are rare, but one 2015 study did find that ashwagandha helped improve lung endurance in 50 healthy athletic adults.10
  • May reduce joint pain – A 2021 study suggested that it might be useful to help manage joint pain in people with arthritis, but again this was a small study and authors acknowledged that studies with more than 100 participants are needed.11
  • May help with neurological conditions – A 2020 study evaluating the link between ashwagandha and brain disorders, concluded it might be a promising drug target. 13 However, they also concluded that because a lot of these neurological conditions are not very well understood, it is hard to know whether ashwagandha affects these conditions directly.12

Please note scientific evidence for this product is very limited and although there are emerging studies, more clinical research needs to be conducted. Please speak to your GP before taking any new products.

What does Ashwagandha do?

Ashwagandha is an adaptogen, a natural agent that reportedly helps the body cope with stress according to this particular study.13  There is a lot of research on the potential effects of ashwagandha, but we still don’t know how it works on the body or if these effects would be seen in larger studies.

One thing that is known is that ashwagandha also contains a large amount of Withanolides, which are one of the primary active ingredients in ashwagandha. The level of Withanolides, which are mainly found in ashwagandha roots, varies from one extract to the other.14

Ashwagandha side effects

As with taking any supplement, it’s important that ashwagandha is taken in line with the manufacturer’s guidance. Ashwagandha is believed to be safe for most people to take, although its long-term effects are unknown.15

Typical doses, taken on a short-term basis, may cause mild to moderate side effects, such as headaches, sleepiness and stomach upsets.15 

You should avoid taking it if you are pregnant, breastfeeding, taking certain medications, or have an autoimmune disease or if advised by your GP.


Is Ashwagandha safe?

Ashwagandha is a natural herbal treatment that is believed to be safe for most people.15

Consider factors such as dosage and speak to your GP if you have concerns. 

 If you are pregnant or breastfeeding, taking certain medications, and other reasons explained in the previous section, ashwagandha should be avoided.

The Final Say

We hope you’re feeling more clued up about ashwagandha, especially when it comes to knowing what it’s used for and potentially, how to start using it yourself.

Ashwagandha has been researched for a range of possible benefits, including reducing anxiety, stress, and fatigue, increasing testosterone in men, improving sexual well-being in all genders, reducing joint pain and helping with better quality sleep. More robust studies are needed to confirm the benefits of Ashwagandha, we do not know if these effects would be replicated in larger studies, but for now, some preliminary research shows promising results and encourages further study.5,6,7,8,9,12

If you do intend to use this ayurvedic herb, speak to your GP first, always read the labels and follow the recommended intake levels. Do not take it if you are breastfeeding, pregnant, or taking medication for anything else.




1. Mishra LC, Singh BB, Dagenais S. Scientific basis for the therapeutic use of Withania somnifera (ashwagandha): a review. Alternative medicine review. 2000. Available at: https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=2bdff82eb23a373885252c87b53135b2fc9adde4
2. Rajeswara Rao BR, Rajput DK, Nagaraju G, Adinarayana G. Opportunities and challenges in the cultivation of Ashwagandha {Withania somnifera (L.) Du-nal}. Journal of Pharmacognosy, ISSN. 2012. Available at: https://www.researchgate.net/profile/Adi-G/publication/264289020_OPPORTUNITIES_AND_CHALLENGES_IN_THE_CULTIVATION_OF_ASHWAGANDHA_Withania_somnifera_L_DUNAL/links/53d79f780cf2631430bfbadf/OPPORTUNITIES-AND-CHALLENGES-IN-THE-CULTIVATION-OF-ASHWAGANDHA-Withania-somnifera-L-DUNAL.pdf
3. Tripathi N, Shrivastava D, Mir BA, Kumar S, Govil S, Vahedi M, Bisen PS. Metabolomic and biotechnological approaches to determine therapeutic potential of Withania somnifera (L.) Dunal: A review. Phytomedicine. 2018. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0944711317301101
4. Lopresti AL, Smith SJ, Malvi H, Kodgule R. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study. Medicine (Baltimore). 2019. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6750292/
5. Akhgarjand C, Asoudeh F, Bagheri A, Kalantar Z, Vahabi Z, Shab‐bidar S, Rezvani H, Djafarian K. Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta‐analysis of randomized controlled trials. Phytotherapy Research. 2022. Available at: https://onlinelibrary.wiley.com/doi/abs/10.1002/ptr.7598
6. Smith SJ, Lopresti AL, Fairchild TJ. Exploring the efficacy and safety of a novel standardized ashwagandha (Withania somnifera) root extract (Witholytin®) in adults experiencing high stress and fatigue in a randomized, double-blind, placebo-controlled trial. Journal of Psychopharmacology. 2023. Available at: https://journals.sagepub.com/doi/full/10.1177/02698811231200023
7. Gopukumar K, Thanawala S, Somepalli V, Rao TS, Thamatam VB, Chauhan S. Efficacy and safety of ashwagandha root extract on cognitive functions in healthy, stressed adults: a randomized, double-blind, placebo-controlled study. Evidence-Based Complementary and Alternative Medicine. 2021. Available at: https://www.hindawi.com/journals/ecam/2021/8254344/
8. Dongre S, Langade D, Bhattacharyya S. Efficacy and safety of Ashwagandha (Withania somnifera) root extract in improving sexual function in women: a pilot study. BioMed research international. 2015. Available at: https://www.hindawi.com/journals/bmri/2015/284154/
9. Chauhan S, Srivastava MK, Pathak AK. Effect of standardized root extract of ashwagandha (Withania somnifera) on well‐being and sexual performance in adult males: A randomized controlled trial. Health Science Reports. 2022. Available at: https://onlinelibrary.wiley.com/doi/full/10.1002/hsr2.741
10. Choudhary B, Shetty A, Langade DG. Efficacy of Ashwagandha (Withania somnifera [L.] Dunal) in improving cardiorespiratory endurance in healthy athletic adults. Ayu. 2015. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4687242/
11. Kanjilal S, Gupta AK, Patnaik RS, Dey A. Analysis of clinical trial registry of India for evidence of anti-arthritic properties of Withania somnifera (ashwagandha). Altern. Ther. Health Med. 2021. Available at: http://www.alternative-therapies.com/oa/pdf/65961.pdf
12. Zahiruddin S, Basist P, Parveen A, Parveen R, Khan W, Ahmad S. Ashwagandha in brain disorders: A review of recent developments. Journal of ethnopharmacology. 2020. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0378874119339182
13. Bonilla DA, Moreno Y, Gho C, Petro JL, Adrián Odriozola-Martínez, Kreider RB. Effects of Ashwagandha (Withania somnifera) on Physical Performance: Systematic Review and Bayesian Meta-Analysis. Journal of Functional Morphology and Kinesiology [Internet]. 2021 Feb 11 [cited 2024 Feb 1];6(1):20–0. Available from: https://pubmed.ncbi.nlm.nih.gov/33670194/
14. Samadi A. Potential Anticancer Properties and Mechanisms of Action of Withanolides. The Enzymes [Internet]. 2015 Jan 1 [cited 2023 Dec 19];73–94. Available from: https://www.sciencedirect.com/topics/neuroscience/withanolide
15. Verma N, Gupta SK, Tiwari S, Mishra AK. Safety of ashwagandha root extract: a randomized, placebo-controlled, study in healthy volunteers. Complementary therapies in medicine. 2021. Available at: https://www.sciencedirect.com/science/article/pii/S0965229920319099
Laura Harcourt

Laura Harcourt


SEO Content Executive

Joined Holland & Barrett: March 2022


Laura brings her passion for health and wellness to life by creating engaging and informative content on the H&B Health Hub.

Her writing journey began during her studies at the University of Reading, where she discovered a love for content while writing lifestyle articles for the student newspaper. After graduation, Laura's experience in the health and beauty world further fueled her passion for the health and wellness industry.

Now, Laura tackles diverse health and wellness topics on the Health Hub, ranging from supporting those navigating menopause to exploring the fascinating world of adaptogenic mushrooms.

Outside of writing, you'll likely find her conquering her ever-growing Goodreads list, mastering the art of Pilates, or spending quality time with Winston, her golden cocker spaniel.
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