What is ashwagandha?

Ashwagandha (Withania somnifera) is a plant native to India, the Middle East, and parts of Africa. Its root has been used in Ayurvedic medicine for over 3,000 years, where it is classified as a rasayana — a category of preparations traditionally associated with vitality and longevity.

In modern supplement science, ashwagandha is categorised as an adaptogen: a botanical compound studied for its potential effects on the body's physiological stress response. The active compounds of interest are withanolides — steroidal lactones found primarily in the root.

Ashwagandha does not have any EU-authorised health claims. No claim for stress reduction, sleep improvement, cognitive function, or any other outcome has been approved under EU Regulation 432/2012, retained in UK law. Everything in this article that relates to efficacy is based on clinical trial evidence, not regulatory approval.

What is KSM-66® and why does it matter?

Not all ashwagandha extracts are the same. The extract type, plant part used, and standardisation process all affect what you are actually consuming.

KSM-66® is a full-spectrum root extract produced by Ixoreal Biomed, standardised to contain at least 5% withanolides. It is extracted using a process based on the principles of "green chemistry" — without alcohol or chemical solvents. It is the most clinically studied ashwagandha extract globally, with over 24 published clinical trials to date.

The distinction between root-only and whole-plant extracts matters. Ashwagandha leaves contain different compound profiles to the root, including withaferin A — a compound that has raised safety questions in some preclinical studies. KSM-66® uses only the root, which aligns with traditional Ayurvedic use and avoids the compounds present in leaves that are less well characterised for safety.

Generic ashwagandha extracts vary widely in withanolide content, extraction methods, and plant parts used. When clinical trials show positive results with a specific standardised extract, those results cannot be automatically applied to a different extract with a different composition. This is why the extract type matters — and why PARTICULAR uses KSM-66® specifically.

What is the EU regulatory status of ashwagandha?

This is a live issue that customers in the UK and Europe are understandably searching for clarity on.

Within the European Union, several member states have moved to restrict or suspend the sale of ashwagandha supplements. Denmark banned ashwagandha in food supplements in 2023. France has added it to its list of banned plants in supplements. Belgium treats ashwagandha supplements as medicinal products requiring special authorisation. Germany and the Netherlands have also taken restrictive positions.

At the EU level, the European Commission's working group of Heads of Food Safety Agencies recommended in 2024 that ashwagandha be prioritised for an Article 8 procedure under Regulation (EC) No. 1925/2006, citing potential effects on reproduction, thyroid hormones, the immune system, and liver function. If this procedure is executed, it could lead to a formal restriction on ashwagandha's use in food supplements across the EU.

The UK position is different. The Food Standards Agency (FSA) has confirmed that ashwagandha root — specifically, non-concentrated aqueous infusions from the roots — has a significant history of consumption in the UK prior to the novel food cut-off date (15 May 1997). As such, ashwagandha does not fall within the scope of the UK's assimilated Novel Foods Regulation for use in food supplements. The FSA launched a call for evidence in July 2024 to gather further safety data, and this review remains ongoing.

This article does not take a position on whether the EU restrictions are justified. What is clear is that the regulatory landscape is evolving, and anyone using ashwagandha supplements should stay informed about developments in their jurisdiction.

What does the clinical evidence say about stress and cortisol?

The most cited clinical trial on ashwagandha and stress used KSM-66® — the same extract that PARTICULAR includes.

Chandrasekhar et al. (2012) conducted a prospective, randomised, double-blind, placebo-controlled study published in the Indian Journal of Psychological Medicine. Sixty-four adults with a history of chronic stress received either 300mg KSM-66® ashwagandha root extract twice daily or placebo for 60 days. The ashwagandha group showed a significant reduction in scores on all stress-assessment scales compared to placebo, including the Perceived Stress Scale, the General Health Questionnaire, and the Depression Anxiety Stress Scale. Serum cortisol levels were also substantially lower in the ashwagandha group.

Salve et al. (2019) — a double-blind, randomised, placebo-controlled study published in Cureus — found similar results. Sixty healthy adults received KSM-66® ashwagandha root extract at varying doses or placebo for 8 weeks. The study reported significant reductions in perceived stress and serum cortisol in the ashwagandha groups compared to placebo.

These are well-designed trials with meaningful results. But the limitations should be acknowledged: sample sizes are modest, the research base is still developing, and the precise mechanism — thought to involve modulation of the hypothalamic-pituitary-adrenal (HPA) axis — is not fully established. Clinical trial evidence suggests that KSM-66® may have a meaningful effect on perceived stress and cortisol levels. It does not constitute proof of a universal stress-relieving effect.

For more on the broader landscape of nutritional support for stress, see our article on supplements for stress and anxiety.

What does the clinical evidence say about sleep quality?

Langade et al. (2019) published a double-blind, randomised, placebo-controlled study in Cureus examining ashwagandha root extract in 60 participants with insomnia. The treatment group received 300mg of ashwagandha root extract twice daily (600mg total) for 10 weeks. The study found significant improvements in sleep onset latency, sleep efficiency, and Pittsburgh Sleep Quality Index (PSQI) scores in the ashwagandha group compared to placebo.

Langade et al. (2021) — a subsequent study published in the Journal of Ethnopharmacology — examined ashwagandha root extract in both healthy volunteers and insomnia patients using a double-blind, randomised, parallel-group, placebo-controlled design. Both groups showed significant improvement in sleep parameters with ashwagandha, with the effect being more pronounced in the insomnia group.

The proposed mechanism is indirect. Ashwagandha does not appear to act as a sedative. Rather, clinical evidence suggests that its effects on sleep may be mediated through its influence on cortisol and the stress response — reducing the physiological arousal that can interfere with sleep onset and maintenance.

Ashwagandha does not carry any EU-authorised health claim related to sleep. These are clinical trial findings only. For a broader look at nutritional approaches to sleep, see our articles on supplements for sleep and magnesium for sleep.

What does the clinical evidence say about cognitive function?

Choudhary et al. (2017) conducted a prospective, randomised, double-blind, placebo-controlled study published in the Journal of Dietary Supplements. Fifty adults with mild cognitive impairment received either 300mg KSM-66® ashwagandha root extract twice daily or placebo for 8 weeks. The ashwagandha group showed significant improvements in immediate and general memory on the Wechsler Memory Scale III, as well as improvements in executive function, sustained attention, and information-processing speed on multiple cognitive tests.

This is a single trial with a relatively small sample size, and it studied a specific population (adults with existing mild cognitive impairment) rather than healthy adults. The results are suggestive, not definitive. Ashwagandha has no EU-authorised health claim for cognitive function — the nutrients that do carry this specific claim are iron, zinc, and iodine.

For more on nutritional support for concentration and mental performance, see our article on supplements for focus and concentration.

What does the clinical evidence say about testosterone and male reproductive health?

Lopresti et al. (2019) conducted a randomised, double-blind, placebo-controlled, crossover study published in the American Journal of Men's Health. Fifty-seven ageing, overweight men (aged 40-70) received either ashwagandha extract or placebo for 8 weeks, then crossed over. The ashwagandha group experienced an 18% greater increase in DHEA-S and a 14.7% greater increase in testosterone compared to placebo. However, no statistically significant differences were observed in fatigue, vigour, or sexual wellbeing between the groups.

It is worth noting that this study used a Shoden ashwagandha extract rather than KSM-66®. While both are standardised ashwagandha root extracts, they differ in extraction method and withanolide concentration. The results are relevant to the broader ashwagandha evidence base but should not be directly attributed to KSM-66®.

There is no EU-authorised health claim for ashwagandha in relation to testosterone or male reproductive health. The nutrient that does carry the authorised claim "contributes to the maintenance of normal testosterone levels in the blood" is zinc. For more on this topic, see our article on supplements for hormone balance.

Is ashwagandha safe?

In the clinical trials cited above, ashwagandha root extract was generally well tolerated at doses up to 600mg per day. Reported adverse effects were typically mild and comparable in frequency to placebo. The most commonly reported side effects include gastrointestinal discomfort — particularly when taken on an empty stomach.

However, there are important contraindications and safety considerations:

Immunosuppressant medications. Ashwagandha has demonstrated immunomodulatory activity in preclinical studies. PARTICULAR excludes ashwagandha from formulas for anyone taking immunosuppressant medications.

Cancer or cancer treatment. Due to ashwagandha's potential effects on immune function and cell proliferation pathways, PARTICULAR excludes it for anyone undergoing cancer treatment or with a current cancer diagnosis.

Thyroid function. Some evidence suggests ashwagandha may influence thyroid hormone levels. Anyone with a thyroid condition or taking thyroid medication should consult their healthcare provider before using ashwagandha.

Pregnancy and breastfeeding. There is insufficient safety data for ashwagandha use during pregnancy or breastfeeding. PARTICULAR blocks its entire service — not just ashwagandha — for pregnant and breastfeeding users at the questionnaire level.

Liver function. Rare case reports of liver injury associated with ashwagandha use have been documented, and this is one of the safety signals cited in the EU's regulatory review. While these reports involve a very small number of cases relative to the volume of global use, they should not be dismissed.

The safety concerns raised by EU regulators are genuine and deserve serious consideration, even where the evidence is preliminary. Anyone with an existing medical condition or taking prescription medication should consult a healthcare professional before supplementing with ashwagandha.

How does PARTICULAR use ashwagandha?

PARTICULAR uses KSM-66® ashwagandha root extract, standardised to at least 5% withanolides, at a dose of 150-300mg per daily serving.

Ashwagandha is not included in every formula. The PARTICULAR algorithm determines relevance based on individual questionnaire responses — specifically, responses relating to stress, sleep, and lifestyle factors. If the algorithm does not identify a relevant need, ashwagandha is not included.

When it is included, ashwagandha is delivered as enteric-coated microgranules — the same pharmaceutical-grade delivery system used for all PARTICULAR ingredients. Each granule is individually coated, allowing targeted release in the digestive tract rather than immediate breakdown in the stomach. For more on how this technology works, see our science page.

PARTICULAR is a food supplement service, not a medical service. Ashwagandha supplementation is not a substitute for professional medical advice, and anyone experiencing significant stress, sleep difficulties, or hormonal concerns should speak to their GP as a first step.

Key takeaways

  1. Ashwagandha (Withania somnifera) is an adaptogenic herb with over 3,000 years of use in Ayurvedic tradition. It has no EU-authorised health claims.

  2. KSM-66® is the most clinically studied ashwagandha extract, produced from root only and standardised to at least 5% withanolides. The extract type matters — results from one extract cannot be assumed to apply to others.

  3. A randomised controlled trial found that 300mg KSM-66® twice daily for 60 days led to significant reductions in perceived stress scores and serum cortisol compared to placebo.

  4. Clinical trial evidence suggests ashwagandha root extract may support sleep quality, with improvements in sleep onset latency and sleep efficiency observed in multiple placebo-controlled studies.

  5. A single trial found improvements in memory and cognitive function with KSM-66® in adults with mild cognitive impairment. The evidence is preliminary.

  6. The EU regulatory landscape for ashwagandha is changing. Several member states have restricted or banned its sale in supplements. In the UK, ashwagandha remains legal for use in food supplements, though the FSA is conducting an ongoing safety review.

  7. Ashwagandha is generally well tolerated in clinical trials at doses up to 600mg per day. PARTICULAR excludes it for users taking immunosuppressants or undergoing cancer treatment, and blocks the entire service for pregnant or breastfeeding users.

  8. PARTICULAR uses KSM-66® at 150-300mg, included only when the personalisation algorithm identifies relevance based on individual questionnaire responses.

Sources cited in this article: