How much does ashwagandha raise testosterone?

Randomized trials report increases in total testosterone in the range of roughly 10 to 17 percent against placebo, which for a man starting at 420 nanograms per decilitre means approximately 40 to 60 nanograms. The most relevant trial in older men, Lopresti and colleagues in the American Journal of Men's Health in 2019, found a 14.7 percent greater increase than placebo in men aged 40 to 70 over eight weeks. That is a genuine but modest change, and it is not large enough to move a man from a clinically low reading into a normal range.

What is the correct ashwagandha dosage?

The dose depends on the extract rather than on capsule weight. A root only extract standardised to at least 5 percent withanolides, such as KSM-66, is used in trials at 600 milligrams daily split as 300 milligrams twice. A root and leaf extract standardised to at least 10 percent withanolides, such as Sensoril, is used at 125 to 250 milligrams daily. Unstandardised root powder may contain under 1 percent withanolides and is not comparable to either at the same weight.

How long does ashwagandha take to work?

Sleep changes are usually the first thing men notice, appearing within two to four weeks in the actigraphy trials. Serum cortisol reductions reach statistical separation from placebo at around four to eight weeks, and the hormone changes reported in trials were measured at eight weeks or later. Ashwagandha does not produce a meaningful acute effect from a single dose, so judging it within the first few days is judging the wrong timescale.

Is ashwagandha bad for your liver?

Ashwagandha has been linked to rare cases of idiosyncratic liver injury. Björnsson and colleagues published a case series in Liver International in 2020 describing five patients with jaundice and a cholestatic or mixed injury pattern beginning two to twelve weeks after starting the supplement, all of whom recovered after stopping. The herb now has a LiverTox entry and Denmark has restricted its sale. The risk appears low in absolute terms, but jaundice, dark urine or persistent right upper abdominal discomfort while taking it warrants stopping and checking liver enzymes.

Can you take ashwagandha every day long term?

Nearly every randomized trial of ashwagandha ran for twelve weeks or less, so continuous use beyond three months has no controlled safety data behind it. The common advice to cycle eight to twelve weeks on followed by several weeks off is a convention rather than an evidence based protocol, but it does keep use inside the window that has actually been studied. Men taking it continuously for years are operating outside the trial evidence entirely.

Does ashwagandha affect thyroid function?

Ashwagandha can raise circulating T3 and T4, an effect deliberately studied by Sharma and colleagues in a 2018 pilot trial in subclinical hypothyroidism where it improved thyroid indices. For a man with normal thyroid function this is generally unremarkable. For a man taking levothyroxine or with hyperthyroidism it introduces an unwanted variable that can shift a stable dose, so anyone in that situation should raise it with the clinician managing the prescription before starting.

Should I take ashwagandha in the morning or at night?

The trials that produced the cortisol and testosterone results used a split dose, typically 300 milligrams in the morning and 300 milligrams in the evening with food. Men who experience daytime drowsiness generally do better weighting more of the dose toward the evening, and men using it primarily for sleep often take the larger portion an hour or two before bed. Taking it with a meal rather than on an empty stomach reduces the nausea and loose stools that are the most common reason for stopping.

Does ashwagandha work for building muscle?

The strength and muscle evidence comes mainly from Wankhede and colleagues in the Journal of the International Society of Sports Nutrition in 2015, where 57 previously untrained men with a mean age near 26 took 600 milligrams daily during an eight week supervised resistance training program and gained more bench press and leg extension strength than placebo. That population was young, untrained and newly training, which is a group that responds strongly to almost any intervention. Whether the same effect holds in a trained man over 40 has not been tested.

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Ashwagandha for Men Over 40: What It Does to Cortisol, and What It Does Not Do to Testosterone

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Supplements 12 min read Sep 3, 2026

Ashwagandha for Men Over 40: What It Does to Cortisol, and What It Does Not Do to Testosterone

The strongest randomized evidence for ashwagandha is about stress hormones and sleep. The testosterone headline comes from a study of young men doing a resistance training program.

Ashwagandha is the most heavily marketed testosterone supplement of the last decade, and it is also one of the few herbal products with genuinely decent randomized data behind it. Those two facts point in different directions. The trials that hold up best are the ones measuring cortisol, perceived stress and sleep, where the effect sizes are consistent across separate research groups. The testosterone story rests on a much thinner base, and the single most quoted number came from men in their twenties who were also lifting weights four days a week. This article separates what the randomized evidence supports from what the label copy implies, covers the dose and extract differences that make one product a fifth as strong as another, and looks squarely at the liver and thyroid signals that most supplement pages skip.

Ashwagandha, Withania somnifera, is an adaptogenic herb from Ayurvedic medicine that has accumulated more placebo controlled human data in the last fifteen years than almost any other botanical sold to men. For a man over 40 the practical question is narrow. Does it reliably do anything to cortisol, testosterone, sleep or training performance at a dose he can actually buy, and what is the cost of finding out. The answer separates cleanly into a well supported half and a badly oversold half.

The well supported half is stress physiology. Multiple independent randomized trials report meaningful reductions in serum cortisol and in perceived stress scores over 8 to 12 weeks, with effect sizes large enough to notice. The oversold half is testosterone. The single trial responsible for most of the marketing enrolled healthy men with a mean age around 26 who were simultaneously running a supervised resistance training program, which makes its hormone result difficult to attribute to the capsule alone.

600 mg

Standard KSM-66 Dose

300 mg twice daily, root only extract

22 to 28%

Cortisol Reduction

reported across separate 8 to 12 week trials

14.7%

Testosterone Change

in men aged 40 to 70 over 8 weeks, against placebo

125 to 250 mg

Sensoril Dose

a different extract, not interchangeable by weight

4 to 8 wks

Time to Measurable Effect

on cortisol and perceived stress

5%+

Withanolide Standard

the number that defines the dose, not capsule weight

Does ashwagandha actually raise testosterone in men?

Ashwagandha produces a small increase in total testosterone in some randomized trials, and the size of that increase is far below what supplement marketing suggests. The most relevant trial for men over 40 is Lopresti and colleagues, published in the American Journal of Men's Health in 2019, which randomized 57 overweight men aged 40 to 70 with mild fatigue to 300 milligrams of a root extract twice daily or placebo for eight weeks. The ashwagandha group showed a 14.7 percent greater increase in total testosterone and an 18 percent greater increase in DHEA-S than placebo. Fatigue, vigor and sexual wellbeing scores did not separate significantly, which is the part of that trial almost nobody quotes.

The number cited far more often comes from a different population. Wankhede and colleagues, publishing in the Journal of the International Society of Sports Nutrition in 2015, gave 600 milligrams daily of a root extract to 57 previously untrained men with a mean age near 26 while putting both groups through an eight week resistance training program. Testosterone rose by roughly 96 nanograms per decilitre in the supplement arm against 18 in placebo, and bench press strength gains were substantially larger. That result belongs to young men beginning a structured lifting program, and extending it to a sedentary 52 year old is a leap the data does not license.

Reported Change in Total Testosterone Against Placebo in Randomized Ashwagandha Trials

How much does ashwagandha lower cortisol, and how fast?

Randomized trials report serum cortisol reductions of roughly 22 to 28 percent over 8 to 12 weeks at doses of 500 to 600 milligrams daily, and this is the most replicated finding in the ashwagandha literature. Chandrasekhar and colleagues, in the Indian Journal of Psychological Medicine in 2012, randomized 64 adults with a history of chronic stress to 300 milligrams twice daily of a high concentration root extract for 60 days and reported a 27.9 percent reduction in serum cortisol against placebo alongside a large drop in Perceived Stress Scale scores. Salve and colleagues, publishing in Cureus in 2019, compared 250 and 600 milligrams daily over eight weeks and found a 22.2 percent cortisol reduction in the higher dose arm with a clear dose response between the two.

The timeline for cortisol is faster than most men expect. Both trials showed separation from placebo by the first measured interim point, generally four to six weeks, with the effect continuing to widen through the end of the study period. This matters because a man taking ashwagandha for stress and giving up at three weeks has not run the experiment properly, while a man who has taken it for six months with no perceptible change in sleep or stress is unlikely to be rewarded by month seven.

Serum Cortisol Falling From Baseline on 600 mg Daily Over an Eight Week Trial Window

This curve is an illustrative representation of the shape and magnitude reported in placebo controlled trials rather than measured data from a single study, and individual responses vary widely around it. The feature worth carrying is that the decline is gradual and roughly linear across the eight week window rather than immediate. Ashwagandha does not behave like a sedative taken for an acute effect, and a man judging it on how he feels ninety minutes after the first capsule is measuring the wrong thing.

Cortisol Is Not a Number Most Men Should Chase

A single morning serum cortisol is a poor summary of a man's stress physiology, because cortisol follows a steep diurnal curve and a draw at 7 am and a draw at 9 am are not the same test. The trials above used standardised timing and still saw wide individual variation. For most men the usable endpoint is not a cortisol value at all, it is whether sleep onset, night waking and perceived stress changed over eight weeks. If a man does want a laboratory picture, a four point salivary curve or a morning draw at a fixed time repeated under identical conditions is more informative than a one off number, and an abnormal result belongs with a physician rather than with a supplement decision.

Does ashwagandha improve sleep?

Sleep is the second best supported effect and in practical terms it may be the primary one. Langade and colleagues, publishing in Cureus in 2019 and again in the Journal of Ethnopharmacology in 2021, ran placebo controlled trials of 300 milligrams twice daily in adults with and without insomnia, reporting improvements in sleep onset latency, total sleep time and sleep efficiency measured by actigraphy alongside subjective sleep quality scores. A 2021 meta-analysis by Cheah and colleagues in PLOS One pooled five randomized trials and found a small but significant improvement in overall sleep, with larger effects in participants diagnosed with insomnia and at doses of at least 600 milligrams daily taken for eight weeks or more.

For a man over 40 the sleep effect and the testosterone question are less separate than they look. Testosterone secretion is tied to sleep architecture, and short or fragmented sleep reduces morning testosterone measurably in controlled sleep restriction studies. If ashwagandha improves sleep continuity in a man who was sleeping badly, a modest testosterone change is a plausible downstream consequence rather than a direct hormonal action of the herb. That framing fits the trial data better than the idea that a withanolide acts on the testes.

The Main Randomized Ashwagandha Trials and What Each One Measured

Trial	Population and design	Dose and duration	Reported finding
Chandrasekhar and colleagues, Indian Journal of Psychological Medicine, 2012	64 adults with a history of chronic stress, randomized, double blind, placebo controlled	300 mg twice daily of a high concentration root extract, 60 days	Serum cortisol reduced by approximately 27.9 percent against placebo with a large reduction in Perceived Stress Scale scores
Ambiye and colleagues, Evidence-Based Complementary and Alternative Medicine, 2013	46 men with low sperm count, randomized, placebo controlled	225 mg three times daily of a root extract, 90 days	Sperm concentration and semen volume increased substantially with an approximately 17 percent rise in serum testosterone
Wankhede and colleagues, Journal of the International Society of Sports Nutrition, 2015	57 untrained men, mean age approximately 26, randomized alongside a supervised resistance training program	300 mg twice daily, 8 weeks	Larger gains in bench press and leg extension strength, greater arm circumference change, and a testosterone rise of roughly 96 ng/dL against 18 ng/dL in placebo
Salve and colleagues, Cureus, 2019	60 healthy stressed adults, randomized, placebo controlled, three arms	250 mg or 600 mg daily, 8 weeks	Dose dependent cortisol reduction reaching 22.2 percent at 600 mg with reductions in perceived stress and improvement in sleep quality
Lopresti and colleagues, American Journal of Men's Health, 2019	57 overweight men aged 40 to 70 with mild fatigue, randomized, placebo controlled	300 mg twice daily, 8 weeks	14.7 percent greater increase in total testosterone and 18 percent greater increase in DHEA-S against placebo, with no significant separation in fatigue, vigor or sexual wellbeing scores
Cheah and colleagues, PLOS One, 2021	Meta-analysis of five randomized controlled trials on sleep outcomes	Doses from 120 mg to 600 mg daily, 6 to 12 weeks	Small significant improvement in overall sleep quality with larger effects in participants with diagnosed insomnia and at doses of 600 mg or more
Björnsson and colleagues, Liver International, 2020	Case series of ashwagandha associated liver injury reported across several countries	Commercial supplement use, onset generally 2 to 12 weeks after starting	Five cases of cholestatic or mixed pattern liver injury with jaundice, all resolving after the supplement was stopped

What is the right dose, and why does KSM-66 differ from Sensoril?

The dose that matters is milligrams of withanolides, not milligrams of powder, and this is where most men buy the wrong product. KSM-66 is a root only extract standardised to at least 5 percent withanolides and is used in trials at 600 milligrams daily, usually split as 300 milligrams twice. Sensoril is a root and leaf extract standardised to at least 10 percent withanolides with a higher withaferin A content, and is used at 125 to 250 milligrams daily. Taking 600 milligrams of Sensoril because that is the number seen in the KSM-66 literature delivers roughly double the withanolide load the Sensoril trials used.

Unstandardised root powder is a third category and it is not equivalent to either. A capsule of plain milled ashwagandha root may contain under 1 percent withanolides, meaning a 600 milligram capsule delivers a fraction of the active compound present in 600 milligrams of a standardised extract. Any product that does not state a withanolide percentage on the label is not comparable to trial doses at all, and price per capsule is a useless comparison across these three categories.

What Is Actually Inside a 600 mg Dose of a Standardised Root Extract

Withanolide glycosides and aglycones, the standardised active fraction
Alkaloids, sitoindosides and other minor phytochemicals
Carbohydrate and starch fraction of the root matrix
Protein, fibre and mineral content of the root
Residual moisture and carrier excipients

This breakdown represents a typical root extract standardised to 5 percent withanolides rather than a laboratory analysis of a specific branded product, and higher concentration extracts shift these proportions. The relevant point is the small gold slice. In a 600 milligram dose only about 30 milligrams is the standardised active fraction, which is why the withanolide percentage on the label decides the dose and the capsule weight tells a man almost nothing.

What Changes and When on 600 mg Daily

Days 1 to 7

Mostly Nothing

Some men report mild sedation or a settled feeling in the evening within the first week, and some report gastrointestinal upset or loose stools, which is the most common reason for stopping early. No hormonal change is measurable in this window

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Weeks 2 to 4

Sleep Moves First

Sleep onset latency and night waking are usually the earliest changes a man notices, and the actigraphy trials show separation from placebo in this range. Perceived stress scores begin to fall before serum cortisol does

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Weeks 4 to 8

Cortisol Separates

Serum cortisol reductions reach statistical separation from placebo in this window across multiple trials, with the effect continuing to widen rather than plateauing at eight weeks

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Weeks 8 to 12

Hormone Changes If Any

The modest testosterone and DHEA-S changes reported in trials were measured at eight weeks, and the sperm parameter trial ran 90 days. This is the earliest point a hormone panel is worth repeating

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Beyond 12 weeks

Unstudied Territory

Almost every randomized trial ran for 12 weeks or less, so continuous use beyond three months has no controlled safety or efficacy data behind it. Cycling eight to twelve weeks on and several weeks off is a convention rather than an evidence based protocol

What are the real risks of taking ashwagandha?

The most substantiated safety concern is idiosyncratic liver injury, and it is rare but genuine. Björnsson and colleagues published a case series in Liver International in 2020 describing five patients with ashwagandha associated liver injury presenting with jaundice and a cholestatic or mixed biochemical pattern, with onset generally two to twelve weeks after starting the supplement and resolution after stopping. Further cases have been reported since and ashwagandha now has an entry in the National Institutes of Health LiverTox database. Denmark's food authority has restricted its sale on safety grounds. This does not make the herb dangerous for most users, but it does mean that new fatigue, dark urine, upper right abdominal discomfort or yellowing of the eyes while taking it is a reason to stop and get liver enzymes checked rather than to wait it out.

Thyroid effects are the second concern and they are relevant to a specific group. Ashwagandha can raise circulating T3 and T4, an effect studied deliberately by Sharma and colleagues in a 2018 pilot trial in subclinical hypothyroidism where it improved thyroid indices. For a man with normal thyroid function that is unremarkable, but for a man already on levothyroxine or with hyperthyroidism it is an unwanted variable, and anyone in that position should not add it without telling the clinician managing the thyroid prescription. Ashwagandha also has immunostimulant properties, which is why it is generally avoided in autoimmune conditions and in anyone on immunosuppressive therapy after transplant.

The routine side effects are milder and more common than either. Gastrointestinal upset, loose stools and nausea are the most frequently reported adverse events in the trials and are usually dose related and worse on an empty stomach. Daytime drowsiness occurs in some men, which argues for putting more of the dose in the evening. A subset of users describe emotional flattening or reduced motivation, which appears in user reports far more than in trial data and has not been formally characterised, but it is consistent enough to be worth watching for in yourself.

A Twelve Week Structure for Testing Ashwagandha Properly

Week 0: Set a baseline you can actually compare against

✓Write down current sleep onset time, number of night wakings and a simple one to ten stress rating, because these are the endpoints the evidence best supports and the ones you will otherwise misremember
✓If you intend to look at hormones, draw total testosterone, free testosterone, SHBG and a morning cortisol at a fixed time before starting rather than after, since a post hoc comparison against a number from two years ago is worthless
✓Check liver enzymes if you have any history of liver problems, drink regularly, or take other supplements or medications metabolised hepatically
✓Confirm you are not on levothyroxine, immunosuppressants or sedatives, and clear it with your prescriber if you are

Weeks 1 to 4: Get the product and the dose right

✓Choose a standardised extract that states a withanolide percentage on the label and match the dose to that extract, meaning 600 mg daily for a 5 percent root extract and 125 to 250 mg daily for a 10 percent root and leaf extract
✓Split the dose morning and evening with food, and weight the evening portion more heavily if daytime drowsiness appears
✓Change nothing else in the same window, since starting ashwagandha and a new training block and a magnesium supplement together makes the result uninterpretable
✓Stop immediately and get liver enzymes checked if jaundice, dark urine, persistent nausea or right upper abdominal pain appears

Weeks 5 to 8: Judge it on sleep and stress, not on feel

✓Score sleep and stress against your week 0 baseline rather than against how you feel on the day, because the effect size is moderate and recall is unreliable
✓Expect no acute sensation from a single dose, since the trial effects accumulate over weeks and an absent immediate response says nothing about whether it is working
✓Note gastrointestinal tolerance honestly, as loose stools and nausea are the most common reasons men abandon it and are often fixed by taking it with a larger meal
✓Resist escalating the dose beyond the studied range, because no trial has shown better outcomes above 600 mg daily of a 5 percent extract

Weeks 9 to 12: Retest and make a decision

✓Repeat the same hormone panel at the same laboratory at the same time of morning if you drew one at baseline, since assay and timing differences are large enough to imitate a real change
✓Compare your sleep and stress scores against week 0 and treat a null result as a null result rather than extending indefinitely in hope
✓Recognise that a testosterone move in the range of 40 to 60 ng/dL is what the trials support, so a man who was clinically low at baseline and is still low is not a candidate for a higher dose, he is a candidate for a clinical evaluation
✓Take any abnormal liver, thyroid or hormone result to a physician rather than adjusting the supplement on your own

So should a man over 40 take it?

Ashwagandha is a reasonable eight to twelve week trial for a man over 40 whose main complaints are poor sleep and high perceived stress, and it is a poor choice for a man whose goal is fixing a low testosterone reading. Those are two different products in the same capsule, and the marketing has deliberately blurred them. The stress and sleep evidence comes from several independent groups using placebo controls and objective measures, which is a stronger position than almost any other herbal supplement occupies. The testosterone evidence comes from a handful of small trials with mixed populations and effect sizes that translate to tens of nanograms per decilitre.

The framing that fits the data is that ashwagandha operates upstream. It appears to reduce the stress hormone load and improve sleep continuity, and whatever happens to testosterone follows from that rather than from a direct gonadal action. For a man over 40 who is sleeping five and a half broken hours a night, that upstream lever is not trivial. It is also not a substitute for the sleep itself, and it is not an alternative to a proper endocrine workup when the numbers on a panel are genuinely low.

Medical Disclaimer

This article is for educational purposes only and is not medical advice. Nothing here diagnoses, treats, cures, or prevents any disease or condition, including hypogonadism, insomnia, anxiety, thyroid disease, or any consequence of ageing. Ashwagandha has been associated with rare cases of liver injury and can alter thyroid hormone levels, and it is generally avoided in autoimmune conditions, in pregnancy, and alongside immunosuppressive, sedative or thyroid medication. Anyone taking prescription medication or with existing liver, thyroid or autoimmune disease should speak with a licensed clinician before using it. Testosterone therapy is a prescription treatment and every decision about it belongs with a licensed clinician working from your bloodwork. The charts in this article are illustrative representations of direction, relative magnitude, and physiological pattern rather than measured trial results, and the studies referenced differ in population, extract, dose, duration, and endpoint, so their figures are not directly comparable to one another.