Remedies › Ashwagandha

Ashwagandha (Withania somnifera)

Also called Withania somnifera, Indian ginseng, winter cherry, KSM-66, Sensoril, Shoden.

Ashwagandha is a shrub in the nightshade family whose root has been used in Ayurvedic medicine for centuries as a tonic. It is now one of the best-selling herbal supplements for stress and sleep, usually as standardized root extracts sold under brand names such as KSM-66, Sensoril and Shoden. It is banned from sale in Denmark, and liver injury has been reported.

What it has been studied for

Beyond Google: what a search won’t show you

Places a normal search rarely reaches: trial registries, FDA report databases, government food-safety pages, patent offices and grant records. Each item links to its primary record.

Unpublished trial
Sensoril for generalized anxiety disorder (phase 2, 120 people, run by the extract maker Natreon)
completed November 2012
A placebo-controlled trial of a branded ashwagandha extract in people with diagnosed generalized anxiety disorder, primary outcome the Hamilton anxiety score. Nearly 14 years after completion the registry shows no results, and we found no paper on PubMed for Sensoril in generalized anxiety. It is about the size of the larger published anxiety trials.
Unpublished trial
Ashwagandha root extract for stress during weight loss (Loma Linda University, 35 people)
completed June 2021
A US university placebo trial, 300 mg twice daily for 12 weeks, primary outcome perceived stress, with sleep among its listed conditions. No results posted and no paper citing the registration after more than five years.
Trial with posted results
How much reaches the blood? Shoden in older adults (OHSU, NIH-funded, 11 people)
ended December 2024; record updated April 2026
Stopped early for a paperwork reason, but its posted numbers show withaferin A, a compound richer in the leaf, in the blood after a root-and-leaf extract: peak 3.02 ng/mL after 240 mg and 13.69 ng/mL after 480 mg, so doubling the dose raised the peak about 4.5-fold. No serious side effects. A 2026 regulatory review ties the theoretical toxicity concerns about leaf preparations to withaferin A.
Trial with posted results
Ashwagandha added to medication for persistent schizophrenia (47 people, terminated by COVID)
ended June 2023
The posted results show no significant difference from placebo on symptoms (P = .31); serious adverse events in 1 of 24 on ashwagandha and 3 of 23 on placebo. A 2026 paper (PubMed 42464773) reports a trial of the same size and design with the same null result, the counterweight to the positive 2018 Sensoril trial.
FDA adverse-event reports
173 reports to the FDA naming an ashwagandha product (CAERS, 2009 to 2026)
counted 28 October 2026
We recounted every openFDA CAERS report whose product names include ashwagandha. 50 record a hospital stay, 35 an emergency visit and 7 a life-threatening event; none records a death. 30 list a liver problem (jaundice in 10, 'liver injury' in 7), 10 of them with a hospital stay. 72 reports name ashwagandha as the only product. Gut symptoms appear in 58, rashes or allergy in 39, anxiety, insomnia, hallucinations or similar in 28, heart symptoms in 13. A report shows what was reported, not what caused it.
Government decision
Denmark: products containing ashwagandha are illegal to sell
page checked 28 October 2026
The Danish Veterinary and Food Administration states that the plant, including its root, is illegal to sell as food in Denmark, citing a DTU risk assessment that found possible effects on sex hormones and reproduction in men and women, and on metabolism, the immune system and the nervous system. The page does not give the date the rule took effect.
Risk assessment
DTU National Food Institute risk assessment of Withania somnifera (memo to the Danish food authority)
15 May 2020
The memo the Danish decision rests on, dated before most of the liver-injury case series were published. It is a risk assessment, not a new study, and we have not reviewed its full reasoning here.
Patent
Withania somnifera extracts for increasing male sperm count (US 6,866,872)
granted 2005
A Japanese patent claiming the sperm-count use years before the placebo trials. A patent is a claim, not evidence.
Patent
Method of treatment or management of stress (US 2007/036873, also WO and Korean filings)
filed 2007-2008
Inventor S. Ghosal; one of 27 patent filings Europe PMC lists for ashwagandha with stress, sleep or fertility words, most of them for multi-ingredient products.
Preprint
Withdrawal symptoms and acute psychosis following discontinuation of ashwagandha
2025
A case posted as a preprint, not peer reviewed, describing psychiatric symptoms after stopping. With the published 2025 withdrawal case, it is a second report of trouble on stopping rather than starting.
Research funding
Who the NIH pays to study ashwagandha (52 projects in NIH RePORTER)
2010-2026
Most projects are lab cancer studies of withaferin A. The largest current one is an Oregon botanicals centre (about $1.1-1.2 million a year, 2020-2024) studying ashwagandha and Centella asiatica in ageing; an Auburn grant tested drug-enzyme interactions. Among the 52 project titles we found no NIH-funded trial of ashwagandha for anxiety, sleep or testosterone.
Japanese journals
J-STAGE: 14 ashwagandha papers, 3 not in PubMed
searched 28 October 2026
The three papers PubMed does not index are a 2007 cell study of leaf extract with cancer drugs and two 2018 conference abstracts in rats (stress adaptation, autism model). No hidden human data.

Sources searched on 2026-10-28: ClinicalTrials.gov, Brand names (KSM-66, Sensoril, Shoden, Witholytin), Europe PMC preprints, Europe PMC patents, FDA CAERS (openFDA), NIH RePORTER, J-STAGE, Danish Veterinary and Food Administration. Where we look

Safety notes

Liver injury: case series from Iceland and the US Drug-Induced Liver Injury Network describe jaundice, itching and cholestatic hepatitis appearing 2 to 12 weeks after starting ashwagandha products, usually resolving within 1 to 5 months after stopping. Source
In a series of 8 people in India with liver injury from single-ingredient ashwagandha, the 3 who already had chronic liver disease developed liver failure and died. Do not take it if you have liver disease. Source
A 2026 review of the published reports counted 25 people with ashwagandha-linked liver injury, including one liver transplant and three deaths, all three in people with cirrhosis. Source
Thyroid: case reports describe an overactive thyroid (thyrotoxicosis) while taking ashwagandha, including a 73-year-old taking it for an underactive thyroid who developed a fast heart rhythm. Trials show a small rise in T4. People with thyroid disease or on thyroid medicine should check with their doctor. Source
Cortisol: trials consistently show lower cortisol, and case reports describe adrenal insufficiency, including a woman whose adrenal glands had not recovered three months after stopping 950 mg a day taken for over a year. Source
The most common side effects in trials are sleepiness, stomach discomfort and loose stools; less common ones include dizziness, nausea, rash and, rarely, hallucinations. Source
In the largest trial (1,002 adults, 600 mg a day for 8 weeks) side effects were no more common than on placebo (5.6% vs 9.2%) and liver tests did not change. Liver injury is rare and unpredictable, so a short trial cannot rule it out. Source
Stopping abruptly: one case report describes a fast heart rate, insomnia and anxiety after a 20-year-old stopped 600 mg a day; the authors raise a withdrawal effect but could not exclude returning anxiety. Source
Pregnancy: safety is not established. Denmark's food authority has made products containing ashwagandha illegal to sell, citing a DTU risk assessment of possible effects on sex hormones and reproduction (see Beyond Google). A 2026 review whose first author works for a supplement-industry company judged the evidence of harm inconclusive. Source
Drug interactions: in lab tests, root and leaf extracts did not measurably block the main drug-processing liver enzymes, but human interaction studies are lacking. Combining it with sedatives, thyroid drugs, immune-suppressants or diabetes medicine has not been tested. Source

Possible links

Where one finding points to others. These are leads for research, not conclusions.

Other conditions

Memory and thinking 189 papers A 2026 meta-analysis of 20 trials found better memory (SMD 0.52) and attention; most trials were small. See on PubMed
Muscle strength and exercise 56 papers Several small trials found greater strength gains with training; the 2026 meta-analysis found gains only in physically active people. See on PubMed
Thyroid 36 papers Can raise thyroid hormone; studied for underactive thyroid, but also linked to thyrotoxicosis in case reports. See on PubMed
Schizophrenia (added to medication) 19 papers One US trial found benefits on negative symptoms; a second, ended early by COVID, found none. See on PubMed
Menopause symptoms 8 papers Small Indian placebo trials report fewer hot flashes and better sleep. See on PubMed
Cancer 419 papers Almost entirely lab and animal work on withaferin A, a compound richer in the leaf than the root. See on PubMed

Same mechanism

Cortisol and the stress-hormone axis (HPA axis) 51 papers The most consistent measured effect in people: morning cortisol falls in most trials (2022 review of human trials, 2026 hormone meta-analysis). See on PubMed Source
GABA, the brain's calming signal (like benzodiazepines) 42 papers Lab and animal studies show GABA-like activity; a 2018 review grouped ashwagandha with kava and valerian on this basis. Not confirmed in human brain studies. See on PubMed Source
Triethylene glycol (a sleep-inducing leaf compound) 6 papers Identified in a 2017 mouse study as a sleep-inducing component of the leaf; the human sleep trials use root extracts. See on PubMed Source

Combinations

Ashwagandha with Rhodiola 37 papers Often sold together as 'adaptogen' blends; a 2026 US trial of a morning blend lowered weekly perceived stress, but the two herbs' shares cannot be separated. See on PubMed
Ashwagandha with saffron 23 papers A saffron, ashwagandha, tryptophan and vitamin B6 product was tested in one open-label study of 46 women; a 2026 review of trials covers each herb separately. See on PubMed
Ashwagandha with fenugreek (testosterone boosters) 17 papers The two herbs with the best-documented testosterone effects, often combined in boosters; combinations themselves are rarely tested. See on PubMed
Ashwagandha with melatonin 12 papers A 2026 trial of 200 adults found the combination improved sleep onset more than either alone. See on PubMed

Who does the research

D. Langade 14 papers D. Y. Patil University School of Medicine, Navi Mumbai. Co-author of most of the Indian sleep, stress and sexual-health trials of standardized root extract, often with J. Salve (6 papers) and K. Debnath (5).
A. L. Lopresti and S. J. Smith 6 papers Clinical Research Australia, Perth (6 papers each). Ran the Shoden, Witholytin and Ashwa.30 trials, including two with null primary results, and a 2021 review of herbs for testosterone.
A. Soumyanath 7 papers Oregon Health & Science University; leads the NIH-funded BENFRA botanicals centre at the university that ran the Shoden blood-level trial in older adults.
K. N. R. Chengappa 3 papers University of Pittsburgh; the US trials of Sensoril in bipolar disorder and schizophrenia.
A. A. Mahdi and M. K. Ahmad 4 papers Chhatrapati Shahuji Maharaj Medical University, Lucknow (4 and 3 papers); the root-powder male infertility studies (2010-2013).

Who pays for it

US National Center for Complementary and Integrative Health (NIH) 8 papers
Other NIH institutes (general, NIGMS, NIA, NCATS) 14 papers
Natreon (maker of Sensoril) 1 papers
Shri Kartikeya Pharma 1 papers

Counts are papers across our three PubMed lists (374 unique records) that list the funder; most human trials list no funder in PubMed. Several trials were run by extract makers, visible only from author affiliations (Sami-Sabinsa, Nutriventia, Gaia Herbs) or company funding (Natreon, Shri Kartikeya Pharma). We did not check full-text conflict-of-interest statements, so unlisted industry funding is possible.

What people report

We read public first-person posts and counted every outcome, good or bad. 40 reports, read on 2026-10-28; 24 mention side effects.

13Helped
4No effect
18Got worse
5Mixed
0Too early

Why these counts prove nothing on their own: people who post are not a random sample, most take other treatments at the same time, and nobody checks the diagnosis. We show them because they tell researchers what to test next.

Read all 40 reports

No effect Tried it for anxiety and noticed little difference; found L-theanine worked better. Mumsnet, 2024-10-18 (No dose or duration given.)
Helped Noticed a difference in anxiety on a KSM-66 product that also contained L-theanine, with magnesium alongside. Mumsnet, 2024-10-21 (Three other calming ingredients at the same time; unsure it would help severe anxiety.)
Mixed It helped her anxiety, but indigestion and stomach aches made her stop. Side effects: indigestion, stomach aches. Mumsnet, 2024-10-21 (No dose or duration given.)
No effect Says it did not really do anything for them. Mumsnet, 2025-09-07 (One-line report; no dose or duration.)
Helped Thinks it helped somewhat, but the effect was very subtle. Mumsnet, 2025-09-07 (The poster is unsure there was any effect at all.)
Helped Anxiety returning in perimenopause eased within two weeks; she has kept taking it for a couple of years. Mumsnet, 2025-09-07 (No dose given; perimenopause symptoms change on their own.)
Helped Started after stopping an antidepressant; slept better and felt calmer within days, later raising the extract dose from 300 to 600 mg. Mental Health Forum, 2022-11-17 (Early reports (days to two weeks); also on quetiapine and melatonin, and had just stopped sertraline.)
Worse Years earlier it had the opposite effect: worse insomnia, tension and strong anger hours after a dose. Side effects: worse insomnia, tension, anger. Mental Health Forum, 2022-11-19 (Recalled from years before; dose not given.)
Helped Two 150 mg capsules at night: sleeping better, with more vivid dreams; effect on stress hard to judge. Side effects: vivid dreams. Mental Health Forum, 2022-12-02 (About two weeks of use.)
Mixed Very helpful for anxiety when taken in the morning, but a night-time dose leaves them feeling worse. Side effects: feels worse when taken at night. Mental Health Forum, 2024-07-07 (The timing explanation is the poster's own theory.)
Worse Says it sped up her hair loss, which did not recover; she will not use it again. Side effects: hair loss. HealthUnlocked, 2022 (Date approximate (shown as four years ago); hair loss with age has other causes.)
Worse After three to four months, a two-day stimulant-like episode then a crash; symptoms persisted after stopping at eight months. Side effects: stimulant-like episode, crash, palpitations, exhaustion. HealthUnlocked, 2026-04 (Long prior illness and many supplements make the cause hard to judge. Date approximate (six months ago).)
Worse Reports a similar crash on ashwagandha; private tests later found autoimmune thyroid disease. HealthUnlocked, 2026-04 (Brief reply; no timing given, and the thyroid disease may be unrelated.)
Worse Each of three tries, including half a 470 mg dose, brought neck and chest tightness and an odd feeling. Side effects: neck and chest muscle tightness, breathing felt difficult, sweating. LongeCity forum, 2013-05-08 (The poster says anxiety could explain the breathing sensation. Thread asked for bad reactions.)
Worse Similar reaction: tight neck and chest, sweating and a headache the next day. Side effects: neck and chest tightness, sweating, headache. LongeCity forum, 2013-05-08 (Thread asked for bad reactions; dose not given.)
Worse Loose bowels, an odd feeling, and says it disturbed their thyroid hormones. Side effects: loose bowels, feeling odd, thyroid hormone change. LongeCity forum, 2013-05-08 (No test results given for the thyroid claim.)
Mixed Over two to three months felt calmer and more focused, but had headaches and an irritable rebound hours after doses. Side effects: headache, irritability hours after dosing. LongeCity forum, 2014-05-28 (Also on a prescribed stimulant; one product was of unknown quality.)
Worse Repeated headaches after doses, which they put down to dehydration. Side effects: headaches. LongeCity forum, 2014-05-28 (Reports only the side effect, not whether it helped.)
Worse Says it made them more depressed and feel odd. Side effects: more depressed, feeling odd. LongeCity forum, 2018-04-16 (Short report; product and dose not given.)
Worse A bedtime dose left them awake from 4 am, detached and with a headache; it never worked for them. Side effects: early waking, headache, feeling detached. LongeCity forum, 2018-04-20 (Says L-theanine causes the same reaction.)
Mixed KSM-66 eased anxiety and overthinking, but brought new pimples and more irritability. Side effects: acne, irritability. LongeCity forum, 2019-06-14 (Several other supplements taken together.)
Helped Anxiety largely lifted within two days of plain root powder; it returned when doses were missed and eased on restarting. Side effects: mild headache. LongeCity forum, 2013-02-17 (On two prescription drugs; later stopped the antidepressant abruptly, which complicates the picture.)
Helped Noticed less hair thinning as an unexpected benefit. LongeCity forum, 2013-05-28 (One sentence; no dose, duration or measurement.)
Mixed More sex drive and better erections, but also more acne. Side effects: acne. LongeCity forum, 2014-02-13 (No hormone test; the poster reads the acne as a sign of higher testosterone.)
Worse Once felt slightly better on it; now each course brings extreme fatigue, brain fog and apathy by day three. Side effects: extreme fatigue, brain fog, apathy. LongeCity forum, 2014-08-24 (Several brands tried; one dose a day.)
Worse Felt apathetic and lethargic after two weeks of 450 mg three times a day. Side effects: apathy, lethargy. LongeCity forum, 2014-08-25 (Short reply.)
Helped Feels great after four weeks of 600 mg a day of a 10% withanolide extract. LongeCity forum, 2014-08-25 (No specific condition or measurement.)
Worse A testosterone booster containing Sensoril left them dull, unmotivated and emotionally flat. Side effects: dullness, low motivation, emotional flatness. LongeCity forum, 2011-09-02 (Multi-ingredient product; the poster suspects the ashwagandha part.)
Worse Taken alone, it made them sluggish and dazed, with no benefit. Side effects: stupor, sluggishness. LongeCity forum, 2011-09-03 (No dose given.)
Worse With selegiline, felt unmotivated and joyless for one to two weeks; motivation returned after stopping both. Side effects: low motivation, loss of pleasure. LongeCity forum, 2011-09-05 (Started a prescription drug at the same time.)
Worse Emotional numbness and little motivation; stopped within a week. Side effects: emotional numbness, low motivation. LongeCity forum, 2011-09-05 (Took several supplements; the thread asked for this reaction.)
No effect About three months with no difference either when starting or after stopping. Mumsnet, 2026-09-19 (No dose given.)
No effect A high-strength product did nothing for them. Mumsnet, 2026-09-19 (One-line report.)
Helped Makes a big difference: less anxiety and stress, more energy. Mumsnet, 2026-09-19 (Short report; no dose or duration.)
Helped Makes a big difference: less anxiety and better sleep. Mumsnet, 2026-09-21 (Short report; no dose or duration.)
Helped Her cycle went back to 29-30 days from 25-26; thinks anxiety is better but is unsure. Mumsnet, 2026-09-21 (She says the anxiety change may be placebo or hormones.)
Worse Strange, vivid dreams left her unsettled and tired; it happened on two separate tries months apart. Side effects: very vivid dreams, waking unsettled and tired. Mumsnet, 2026-09-21 (Two short trials of one to two weeks.)
Worse After two nights felt odd and foggy-headed, like starting antidepressants years ago, and stopped. Side effects: feeling odd, foggy head. Mumsnet, 2025-09-12 (Only two doses.)
Helped Night waking improved; her Fitbit showed deep sleep up by at least a third. Mumsnet, 2026-01-22 (Consumer sleep trackers estimate deep sleep imprecisely; also tried magnesium.)
Helped Very helpful over two years; anxiety and poor sleep come back when she misses a few days. Mumsnet, 2023 (Exact post date not captured (thread from October 2023); also takes magnesium.)

Checked against PubMed on 2026-10-28.