Ashwagandha Benefits: The Cortisol Drops. Feeling Better Is a Separate Question.

If you are stressed, your cortisol will probably go down.

Whether you feel any better is a separate question. Of the two reviews that measured both, one found people’s own stress ratings fell too; the other could not show that they did.

The question that should frame everything else

In 2025 a systematic review pooled two things side by side from ashwagandha trials: cortisol — the stress hormone you can measure in blood — and Perceived Stress Scale scores, which is the questionnaire where people say how stressed they actually feel. [1]

Cortisol dropped, clearly and significantly. Perceived stress did not reach significance — p = 0.40, which means the result is compatible with nothing happening. But the range of plausible answers ran from a large drop in stress to a modest rise, so the review could not rule out a real benefit either.

This is the oldest trap in health research and it has a name: a surrogate endpoint. Cortisol is a stand-in for stress. It is easy to measure, it moves, and it makes a great bullet point. The thing you actually care about — how you feel on a Tuesday afternoon — is harder to shift and harder to measure, and in this analysis it could not be shown to shift.

So does that settle it? No. A 2024 review pooled the same two measures, from nine trials in 558 people, and found that both fell: the questionnaire scores as well as cortisol. [13] A 2025 review of three trials in people with diagnosed mental disorders found perceived stress fell too, and rated its own evidence low certainty. [14] So the felt outcome is not a clean no. It is a weakly supported yes with one review dissenting, and here is where it gets genuinely complicated rather than conveniently simple.

The spectacular number, and why it should worry you

The headline result for ashwagandha and anxiety comes from a 2022 meta-analysis of 12 trials in 1,002 people. It found a standardised mean difference of −1.55 for anxiety and −1.75 for stress. [2]

A standardised mean difference puts different studies on one scale: 0.2 is a small effect, 0.5 moderate, 0.8 large. So 1.55 is not just large. It is enormous. Prescription drugs for generalised anxiety averaged 0.39 against placebo, on the same kind of scale, in one analysis of 21 trials. [15]

Which is exactly why you should look at the next number. The heterogeneity was 93.8%.

Heterogeneity is how much the trials’ results differ from one another. The 93.8% figure, called I², is the share of that spread that is more than chance would produce, so at 93.8% nearly all of it is more than luck. What the figure does not tell you is how the trials differed. They could all have found anxiety falling, some by a little and some by a lot; or some could have found a fall and others next to nothing. The per-trial results that would show which are in the paper’s full text, and we have not been able to read it. Either way, an average laid over a spread that large is not the reliable summary it looks like.

The authors were straightforward about this. Their own assessment: “we identified that the certainty of the evidence was low for both outcomes,” and “further high-quality studies are needed to firmly establish the clinical efficacy of the plant.” [2]

That caveat is in the paper. Look for it the next time you see the −1.55 quoted.

Where the evidence is actually decent: sleep

This is the claim with the cleanest support, and it is not the one on the front of the bottle.

A 2021 meta-analysis of five randomised trials in 400 people found a significant effect on sleep — a standardised mean difference of −0.59, which is moderate on the scale above rather than spectacular; the review’s authors call it “small but significant”, and rate the certainty of that evidence moderate, the second of four grades. [3] It was larger in three specific circumstances: in people actually diagnosed with insomnia, at doses of 600 mg a day or more, and over treatment lasting at least eight weeks.

Ashwagandha also improved how alert people felt on waking. It did not significantly improve quality of life.

Worth knowing about that review, because it is unusually candid: it declares itself unfunded, it notes that all five trials were conducted in India, and it records that one of them was partly sponsored by the manufacturer. [3]

Ashwagandha for men and for women — the hormone numbers

A 2026 meta-analysis pooled 23 randomised trials covering 1,706 people and measured what actually happens to circulating hormones. [4] It is the most useful single answer to the men-versus-women question, because it reports both. Not every trial measured every hormone, and the counts below say how many did.

Cortisol fell on average across the 12 trials that measured it. The headline figure, −1.18 on the standardised scale, comes from the nine run in people with raised stress. That is large, but the authors found signs of publication bias — small trials with disappointing results tend not to get published — and the result shifted when single trials were left out. [4] Serotonin rose. Testosterone was measured in eight of the trials. Pooled from the six that included men, it rose in men by 57.43 ng/dL. In women it rose by 5.09 — a change the analysis could not tell apart from zero, and the difference between the sexes was itself statistically significant. Estradiol did not move in either group.

What is 57 ng/dL? It is a real, measurable change, and it is not testosterone replacement therapy. We are deliberately not converting it into a percentage, because that needs a baseline the meta-analysis does not report, and a made-up denominator is exactly the trick this site exists to catch other people doing.

A broader 2021 review of 13 herbs across 32 studies puts it in context: ashwagandha and fenugreek were the two with positive testosterone findings in men, but across the whole field only 9 of 32 studies showed a statistically significant increase at all. [5]

The thyroid question, on five small trials

This matters if you take thyroid medication, and the honest answer has two halves.

Only five of those 23 trials measured TSH, the pituitary hormone that tells the thyroid how hard to work; four measured T3 and three T4, the thyroid’s own hormones. They were a mixed group: healthy volunteers, stressed adults, people with bipolar disorder, and the subclinical-hypothyroid trial described next. Pooled, TSH and T3 did not move, and T4 rose modestly. [4]

But a 2018 trial ran specifically in 50 people with subclinical hypothyroidism — a mildly underactive thyroid without obvious symptoms — and found significant changes in all three: TSH, T3 and T4. [6] Its authors call it a pilot study, and it is one of the five in that pool.

What that leaves is thin. The pooled result already includes the one trial that moved all three hormones, so it cannot show that a healthy thyroid is left alone, and the idea that a borderline thyroid responds rests on that single pilot of 50 people. If you are on levothyroxine or being monitored for thyroid function, that is a conversation with the person managing it — not because ashwagandha is dangerous to your thyroid, but because it may be active on it, and your dose was calculated without it.

Can ashwagandha cause anxiety?

It is sold to calm you down, so the question sounds backwards. People ask it anyway, and an AI search answer we saved on 20 October 2026 opens with “Yes, ashwagandha can cause or worsen anxiety”, calling it a “paradoxical reaction”. The page it cites for that sentence is a telehealth company’s blog, which sells online anxiety treatment and cites no study. A health-news site in the same answer says “Not typically” [23]. So which is it?

The short answer first. In the placebo-controlled trials that counted side effects, anxiety, agitation, restlessness and insomnia came up rarely, and about as rarely on ashwagandha as on a dummy pill. Most of those trials ran for two or three months, and the biggest left out people with most psychiatric diagnoses. Beyond them sit case reports and drug-safety databases, which can show that something happened to someone, never how often [24] [25] [14].

What the trials recorded

The biggest test is a single 2026 trial of 1,002 adults with stress and anxiety (the same number as the twelve trials in the 2022 review above, by coincidence), run at 15 sites in India, Australia, the US, Portugal and Nigeria, though 888 of them were enrolled in India. Half took 600 mg a day of a root extract, the most-tested amount on this page, for eight weeks; half took a capsule of starch. People with panic disorder, depression and several other psychiatric diagnoses, and anyone on antidepressants, were left out. On ashwagandha, one person reported restlessness, one irritability and one insomnia. On placebo, one reported insomnia and one palpitations [24].

The commonest complaints were nausea, dry mouth and headache. Nausea came up in 2.0% on ashwagandha against 3.2% on placebo, diarrhoea in 0.6% against 0.4%, vomiting in 2 people against 0. Counting everyone with any side effect at all, it was 26 of 498 (5.2%) on ashwagandha and 39 of 504 (7.8%) on placebo, a gap the paper calls not statistically significant, meaning chance could easily account for it [24].

Who ran it matters. It was paid for by the maker of the extract it tested: the funder is the company the extract’s brand lists on its website as its Indian office, which the trial’s Indian registry entry names as its sponsor and payer, and the extract came from the same maker’s US company. It is the same branded extract as the two stress trials above, and two of its five authors also wrote the 2019 one. The trial was registered, in India and the US, with anxiety scores as its main measure. This paper calls itself the safety report from a broader trial whose main focus is stress and anxiety, and names safety as its own primary outcome. By 20 October 2026, two and a half years after the last participant’s final visit in April 2024, we could not find the anxiety results published with their numbers, in a journal, as a preprint or in either registry entry. The extract’s maker does state them, on its website: it says the trial “significantly reduced stress, anxiety and serum cortisol levels, as compared to the placebo group” (in research, “significantly” means unlikely to be chance, not large), calls that preliminary research not yet peer-reviewed, and gives no figures [24]. A plan of the trial, written by two of the safety report’s authors and a member of the funder’s medical-affairs team, was published online in August 2026. It sets out what the trial would measure, anxiety and stress scores and blood cortisol, and reports no results [36]. And the safety report says that all 1,002 people finished the eight weeks [24] [12].

A 2026 systematic review gathered 23 trials of root extracts in 2,317 generally healthy adults, stressed adults and people with insomnia among them, and listed each trial’s side effects. That 1,002-person trial is 43% of everyone in it, the biggest by far. In the other 22, the side effects listed are stomach upsets, headaches, drowsiness, colds, fevers and the like; anxiety, agitation and restlessness do not appear. But 12 of the 23 trials described no side effects at all, the review could not pool the rest because they were reported so unevenly, and it rates its own evidence on side effects as low certainty, the second-lowest of the four grades reviewers use. It had no outside funding; two of its six authors have been paid to consult or speak for supplement companies, some of which distribute ashwagandha [25].

What about people whose mental health is already fragile, where a jittery reaction would matter most? The 2025 review of trials in people with diagnosed mental disorders, cited above, pooled five trials, 287 people, that counted side effects of any kind. They came out about as common on ashwagandha as on the comparison: an odds ratio of 0.99, where 1 means no difference, with a range of plausible answers from 0.54 to 1.82, so the odds of a side effect could be roughly half as high or nearly twice as high. Read that figure loosely. By our reading of the trials’ own papers, the review’s counts for two of them, both described further down, are not what its heading says. For the 2000 anxiety trial it entered the people who dropped out because of side effects, 2 against 3; for the bipolar trial its numbers, 19 of 24 against 26 of 29, do not match that trial’s own count of people reporting any side effect, 13 of 30 against 19 of 30 (our arithmetic from its table) [14] [29] [27]. The heaviest-weighted trial, 42% of the result, is of 70 adults with mild to moderate depression and anxiety; the company that markets its extract paid for it and supplied the capsules, and four of its six authors work for that company. Two of the five trials did not test ashwagandha on its own: that one added piperine, a black-pepper extract used to increase absorption, and another gave ashwagandha inside a package of naturopathic care [14] [26].

Two US trials looked at exactly the people you would worry about. In 60 adults with bipolar disorder, steady on their usual medicines, 500 mg a day for eight weeks left their ratings for mania and anxiety low and steady; the authors noted no worsening, and palpitations came up once, on placebo [27]. In 66 adults with schizophrenia whose symptoms had flared, given 1,000 mg a day for 12 weeks on top of their antipsychotics, 2 people on ashwagandha were recorded as hyperactive against 0 on placebo, and 2 against 1 as having their psychiatric symptoms worsen, while anxiety was recorded in 0 against 2, and confusion in 0 against 2. Those counts come from the trial’s registry record, which lists the side effects that struck at least one person in 20 in either group. Sleepiness was the commonest, 7 of 33 against 3 of 33, and the paper reports that the gaps in those side effects were not statistically significant [28]. Both trials were small, and both were paid for by non-profit research funders, with the extract and the dummy pills supplied by the company that makes the extract.

Can ashwagandha cause insomnia?

The trials give little sign of it. Sleep is this page’s best-supported claim, and in the 1,002-person trial insomnia came up once on ashwagandha and once on the dummy pill [3] [24]. A small trial tilts the other way: in a 2000 trial of 39 people with anxiety disorders, 2 of the 17 on ashwagandha whose side effects it tabulated reported decreased sleep, against 0 of 16 on placebo. Those numbers are too small to tell from chance, and decreased sleep is not among the effects its authors single out [29]. Poor sleep also turns up among the drug-safety reports described below [19].

The sleep-related side effect the trials and regulators flag more often is the opposite one: drowsiness. It was the commonest complaint in the schizophrenia trial, and the 2000 trial recorded more drowsiness (2 against 0) and heaviness of the head (4 against 1) on ashwagandha, in the first few days only [28] [29]. The biggest trial is the exception: it recorded drowsiness only on placebo, in 2 people against none [24]. The US National Institutes of Health’s fact sheet lists drowsiness among the common side effects, with loose stools and nausea, and calls them usually mild; the experts behind France’s food-safety agency’s opinion advise against ashwagandha when driving or using machines, or alongside anything that sedates, because trials have shown it can make people sleepy [30] [19].

What the case reports describe

A trial can tell you how often something happens. A case report can only tell you that something happened once, to one person, and that the doctors who wrote it up suspected the supplement. Keep the two apart.

One documented route from ashwagandha to a racing heart is the thyroid, which the thyroid section above found it may be active on. The NIH fact sheet counts three published reports of an overactive thyroid, thyrotoxicosis, in women taking ashwagandha, and in all three the symptoms went when the ashwagandha stopped [30]. In one, a 73-year-old woman with an underactive thyroid had swapped her prescribed thyroid hormone for ashwagandha two years earlier. She arrived with palpitations, chest pain, tremor, irritability and a heart rate of 173, and her symptoms had gone two weeks after stopping. Her doctors point out that some thyroid supplements have been found to contain thyroid hormone itself; the paper does not report testing hers [31].

Another documented route is what else is in the bottle. A 2024 conference abstract from US toxicologists describes a 50-year-old man brought to hospital with agitated delirium and a racing heart after stirring a “generous tablespoon” of an ashwagandha product bought online into a smoothie. Tests found atropine, a drug that in overdose speeds the heart and brings on delirium, in his urine and in the product; his confusion and his heart rate improved within an hour of a drug that reverses its effects. The toxicologists wrote that ashwagandha, though a member of the nightshade family, had not been found to contain atropine. Their hypothesis was an adulterant, something added to or contaminating the product; the laboratory found atropine in his product and not in a control sample, and the abstract does not say where it came from [35]. Whether the plant itself can carry atropine is less settled than that sentence suggests. France’s food-safety agency lists tropane alkaloids, the chemical family atropine belongs to, among the plant’s main compounds, though the ones it names from the root are not atropine; and a 2025 laboratory analysis of roots grown in Egypt reported a match for atropine itself, identified by comparing its chemical fingerprint with a reference library, with no test against pure atropine reported, and given only as a share of the sample’s signal, not as an amount [19] [37].

Then there is the warning, in the telehealth blog and the AI answer, that stopping suddenly brings “rebound anxiety”. The blog cites nothing for it [23]. In the medical literature we found two case reports. In a 2025 one, a 20-year-old student taking 300 mg twice a day, who also vaped cannabis, stopped, and two days later had a racing heart, insomnia, no appetite and anxiety, for a week; three earlier visits had diagnosed a panic attack without anyone asking about the supplement, and his tests were normal. His doctors think it may have been withdrawal, and say the anxiety he had been taking it for coming back could also explain it [32]. In the other, posted the same year as a preprint, a report not yet checked by other scientists, a 35-year-old man with a long-standing anxiety disorder stopped after about a year, giving up green tea, turmeric and biotin at the same time, and had panic attacks and intense anxiety. His antidepressant dose was doubled (the report says he did it without his doctor’s knowledge; his own account, printed with it, says his family doctor suggested it), and about six months after stopping he had a manic episode with psychotic symptoms that put him in a psychiatric ward. His doctors say the anxiety could be rebound or his illness resurfacing, and that the higher antidepressant dose may have contributed to the mania [33]. Against that, a 2000 trial stopped everyone’s tablets abruptly after six weeks; it did not formally look for withdrawal, but its clinical records noted none in either group [29].

What regulators say about mood and sleep

Do the official safety reviews list anxiety? The NIH fact sheet’s list of side effects does not include it: its common side effects are loose stools, nausea and drowsiness, it calls ashwagandha well tolerated for up to about three months, and it says its long-term safety is not known [30]. France’s food-safety agency, in the 2024 opinion described further down, did find anxiety in the reports it gathered from drug-safety databases. It is among the most frequent complaints in the 73 reports in the World Health Organization’s database, and anxiety, panic attacks and poor sleep are among the most often reported in the 29 in the US Food and Drug Administration’s, alongside liver problems. But in every report from the US and Canadian databases, ashwagandha had been taken with other ingredients or medicines [19]. The Dutch public-health institute’s 2024 assessment, also below, looked at 28 trials, found only mild side effects, and in none of them did side effects differ significantly from the control group [20].

Can you take it with an antidepressant such as sertraline, sold as Zoloft? None of the three official documents we read, from the NIH and the French and Dutch agencies, lists antidepressants among the medicines ashwagandha may interact with. What they do list is longer than any one paragraph, so here is a selection, starting with the medicines a reader of this section is most likely to take. Sedatives, anti-anxiety drugs among them: the Dutch report passes on German risk assessors’ advice not to take ashwagandha with alcohol, sedatives or anxiolytics (anti-anxiety drugs), and both European documents cite a World Health Organization caution about barbiturates and two benzodiazepines, diazepam and clonazepam (sold as Valium and Klonopin). The French agency advises anyone on a sedative not to use ashwagandha; the Dutch report says the worry that it strengthens benzodiazepines and other sedating drugs rests on pharmacological theory. Thyroid medicines: thyroid hormone, the one interaction the Dutch report, citing a drug-interaction database, rates probable, and, in the French opinion, drugs for an overactive thyroid. Medicines for diabetes, for blood pressure and for damping down the immune system. And the French opinion passes on the warning Poland requires on these supplements: not with sedatives, sleeping pills or epilepsy drugs [30] [19] [20]. One trial on this page bears on the question: in the bipolar trial above, 19 of the 30 people on ashwagandha, and 18 of the 30 on placebo, were also taking an antidepressant, and the authors call the side effects minor. It was small, and not designed to study the combination [27]. Another record comes from Poland, where a university drug-safety centre linked 30 side effects reported in 2021 and 2022 to an adaptogen taken with an antidepressant; 7 involved ashwagandha. None of the seven was anxiety: the one with sertraline was severe diarrhoea that put a 36-year-old man in hospital [34].

This is journalism, not medical advice. If you take a prescribed medicine for anxiety or depression, or have thyroid or liver disease, ask your prescriber before taking ashwagandha.

Rated in words, the questions people ask. That ashwagandha makes people anxious, agitated or restless: Unsupported, of the tested kind. The placebo-controlled trials that counted those complaints found them rare, and about as rare as on a dummy pill, in stressed adults and in people with bipolar disorder and schizophrenia alike [24] [25] [27] [28]. They were short and mostly company-linked, and a reaction that strikes one person in a thousand would show up, on average, about once in every two trials the size of the biggest, with 498 people on the herb (our arithmetic), so a rare reaction can slip through. The case of agitated delirium described above is a single report: its toxicologists found atropine in the product and suspected an adulterant, without establishing where the atropine came from [35]. That it causes insomnia: Unsupported, of the tested kind. In the biggest trial insomnia came up once on each side, and a small trial’s tilt the other way, decreased sleep in 2 people against none among 33, is too small to tell from chance; the sleep effect the trials record more often is drowsiness [24] [29] [28]. That stopping it suddenly brings rebound anxiety: Preliminary, on two case reports whose own authors offer another explanation, against one trial from 2000 that noted nothing when the tablets stopped, without formally looking [29] [32] [33]. That it can push a thyroid into overdrive, with the racing heart that brings: Preliminary, on case reports and the small trials in the thyroid section above [4] [6] [30] [31]. These ratings leave the page’s own, which is about stress, where it was.

Side effects: the liver, reported properly

This is the part of the ashwagandha story that gets either ignored or turned into a scare. Neither is useful, so here is what is actually documented.

In 2020, a case series from Iceland and the US Drug-Induced Liver Injury Network described five people who developed liver injury after taking ashwagandha supplements. [7] All five became jaundiced. The paper puts onset at 2 to 12 weeks after starting, though its own case table records symptoms beginning anywhere from day 5 to day 116. The injury was cholestatic or mixed — cholestatic is the bile-flow type, and mixed means the liver cells themselves were hit as well — and bilirubin, the yellow pigment behind jaundice, stayed high for 5 to 20 weeks; two of the five had itching. Nobody developed liver failure. Liver tests recovered in the four who were followed up, most within one to five months (one took nine to clear fully); the fifth was lost to follow-up.

One detail in that paper closes off the usual escape hatch. Chemical analysis confirmed ashwagandha was in the supplements, and “no other toxic compounds were identified.” [7] This was not a contamination story. The expert committee rated the herb the cause as definite in one case, highly likely in two, probable in one and possible in one, and in one case a second herb, rhodiola, may also have played a part.

Then a 2023 series from multiple centres in India reports the other end of the range. Among eight patients injured by single-ingredient ashwagandha, five had underlying chronic liver disease. Three of those arrived in acute-on-chronic liver failure. All three died. [8] In the patients without existing liver disease, the injury was prolonged but self-limiting — the same picture as Iceland. Across the eight, symptoms began anywhere from day 14 to day 540 after starting.

So the risk is not one thing. The worst outcomes cluster in livers that were already damaged, but a healthy liver is not a guarantee. A 2023 US case report describes a 41-year-old woman, with no liver disease reported, whose liver failed after two months of ashwagandha taken alongside a progesterone supplement; she needed a transplant, and the case’s causality score rated ashwagandha a possible cause. Counting her and the three deaths in India, 4 of the 25 published cases ended in death or a transplant. [9]

Now the denominator, because scale matters

A 2026 scoping review searched the literature through December 2025 and found 13 publications describing 25 patients. That counts cases written up in English-language, peer-reviewed journals; the review left out the first report, which was in Japanese, and says others may have been missed. [9]

How many people are taking it? A 2024 analysis of national US survey data from 2017 to early 2020 estimated that about 1.25 million American adults had taken ashwagandha in the previous 30 days. That rests on 28 users in the survey sample, so the range the true figure probably sits in runs from about 760,000 to 2.1 million. The paper’s headline number, 15.6 million, is for any of six liver-linked botanicals, and turmeric alone accounts for about 11.4 million of it. [10] The authors point out that the six-botanical total is comparable to the 14 million people prescribed simvastatin, a cholesterol drug that can also, rarely, injure the liver. [17]

So can you divide one number by the other and call it your risk? No. The published cases are only the ones somebody wrote up, and the review itself says case reports “cannot quantify attributable risk”. [9] What can be said is that published cases are few against a million-plus users, and Australia’s regulator, which holds its own reports of side effects, calls the risk very rare. [16] That does not mean zero, it does not mean the cases are not real, and it does not help you at all if you have cirrhosis.

What the simvastatin comparison should make you notice is the asymmetry. Simvastatin comes with a prescriber, and with a label telling that prescriber to consider a liver test before starting and to stop the drug if serious liver injury appears. [17] Nearly all of the ashwagandha users in the survey, 96% of a small sample, said no health care provider had recommended it. [10]

What the authorities have said

Here is what authorities in five countries have said, each for its own reasons. Denmark’s food authority says ashwagandha is illegal to sell as a food there, because a risk assessment by the Technical University of Denmark found negative effects on sex hormones and reproduction in both men and women, and that the plant can affect metabolism, the immune system and the central nervous system. [18] The ban dates from 2023, [4] and the reasons Denmark gives do not include the liver. France’s food-safety agency, ANSES, said in April 2024 that the data were too poor to set a safe intake, and advised people with liver, thyroid or heart conditions or hyperandrogenism (excess male hormones), pregnant women, and anyone taking sedatives not to use ashwagandha supplements, and breastfeeding women and under-18s not to either, as a precaution. [19] In the Netherlands, the national public-health institute, RIVM, advised consumers in March 2024 not to use ashwagandha preparations, as a precaution and especially in pregnancy, citing reports of harm to the liver and to thyroid-hormone and cortisol levels, [20] and the Dutch pharmacovigilance centre, Lareb, which collects reports of side effects, warned about liver toxicity in September 2023 and again in July 2025, after eight more reports. [21]

Australia’s Therapeutic Goods Administration issued a safety advisory in 2024 and followed it up on 7 July 2026. Liver injury, it says, is very rare but can be severe: 11 possible cases have been reported to it, none fatal and none needing a transplant; it knows of at least four published cases of liver failure abroad, one of which needed a transplant; and people who have or have had liver problems should avoid the herb. Its summary of the Dutch reports puts onset anywhere from 6 weeks to 22 months after starting. [16] And in India, the food regulator told manufacturers on 16 April 2026 that only the root and its extracts are permitted in supplements, not the leaf, the day after the traditional-medicine ministry barred the leaf from its own products, citing possible safety concerns from the leaf’s higher levels of reactive withanolides, the plant’s active compounds. The ministry recommends the root. [22]

Dose, timing, and what the trials actually did

Dose. The two stress trials cited here gave 300 mg twice a day, 600 mg in all [11], or 125 or 300 mg twice a day, 250 or 600 mg in all [12]. The sleep trials used 120, 250 or 600 mg a day, and the effect was stronger at 600 mg a day or more. [3] So 600 mg a day, as two doses of 300 mg, is the most-tested amount; none of these trials used 300 mg a day. Across the 23 trials in the hormone review, daily doses ran from 60 to 6,000 mg, and the extracts’ strength varied just as widely, from 0.2% to 35% withanolides. [4]

Timing. The two stress trials cited here dosed twice a day, after food, without naming a time of day. [11][12] None of these studies tested whether a particular hour matters, so anyone telling you there is a magic window is going beyond the evidence.

How long. Eight weeks or more, in the trials where the sleep effect was largest. [3] Nothing here is a same-week proposition.

One caveat that runs under all of it: the two stress trials cited here both used the same branded extract, KSM-66, described as “provided by” and “manufactured and gifted by” its manufacturer. [11][12] The 2012 paper declares no funding and no conflict of interest, and that declaration deserves to be reported alongside the supply arrangement rather than instead of it. The two are typical. Every one of the nine trials behind the hormone review’s headline cortisol figure was paid for by a company, used product a company supplied, or had company staff among its authors, and so did at least four of the five sleep trials; the funding row at the top names them. And a branded extract means the dose you buy may not be the material that was tested, and withanolide content — the active fraction — varies between products.

The verdict

Ashwagandha is not nothing, which makes it more interesting than most of what we check. On average, it lowers a stress hormone. It has a moderate, replicated effect on sleep. It nudges testosterone in men and not in women. It is measurably active on the endocrine system.

What it has not clearly done is make people report feeling less stressed — the one outcome the whole category is sold on. Of the two analyses that measured cortisol and perceived stress side by side, one found both fell and the other found the first and could not show the second. The analysis with the spectacular anxiety numbers carries 93.8% heterogeneity and a low-certainty rating from its own authors, and the 2025 review in people with mental disorders rates its stress evidence low too. And the evidence base is narrow: for sleep, five trials, all from one country, largely one supplier’s extract, and across the board, trials mostly paid for, supplied or staffed by companies that sell extracts.

We have it at Preliminary. Something real is happening in the bloodwork. Whether it reaches the part of you that wanted the bottle is not yet established.

If you try it: the most-tested amount is 600 mg a day, as two doses, for at least eight weeks; sleep is the claim with the best support; and you should talk to a doctor first if you have any liver condition, take thyroid medication or sedatives, or are pregnant. If you develop jaundice (yellowing skin or eyes), dark urine, or persistent itching, stop and get liver tests; Australia’s regulator adds nausea, vomiting, unusual tiredness, weakness, stomach pain and loss of appetite to that list. [16] Jaundice is the usual pattern in the published cases. Most cases began within weeks to a few months of starting, but reports run from days to 22 months, so a long run without trouble is not a clean bill of health. [7][8][9][16]

What would move this to Supported: trials outside India, using extracts from more than one supplier and paid for by someone other than the companies that sell them, powered for perceived stress rather than cortisol, and reporting whether people felt better rather than whether their bloodwork did.

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