Ashwagandha and Testosterone: What the Trials Show and Who Should Be Cautious

The clip runs eleven seconds. A man in a gym mirror holds up a brown bottle, says one word, and the caption promises his testosterone “doubled in a month.” By the time it reached my feed it had been stitched, duetted and translated into four languages. As of September 2026, that single word, ashwagandha, is one of the fastest-rising men’s health searches, and the phrase “ashwagandha testosterone” sits near the top of the list.

Two things pushed it there at once. On one side, supplement marketing and fitness influencers have turned a handful of small clinical trials into a muscular headline. On the other, liver specialists have been quietly logging case reports of people whose jaundice began a few weeks after they started the capsules.

Both stories are real. Neither is the whole story. This piece walks through what the trials measured, what the numbers mean for an actual body, and who should pause before reaching for that bottle.

What changed recently in the ashwagandha testosterone conversation

Ashwagandha has been part of Ayurvedic practice for centuries, but the modern testosterone claim is young. The trials that anchor it were published between 2009 and 2022, and most readers are meeting them now only because short-form video has compressed them into a slogan.

A few dated facts explain the current surge. In 2023 the NIH Office of Dietary Supplements released its first dedicated ashwagandha fact sheet, pulling together the scattered trials on stress, sleep, athletic performance and male hormones in one place; that document is now the reference most clinicians reach for when a patient asks. In the same period, the NIH LiverTox database, which catalogs medicines and supplements linked to liver injury, expanded its ashwagandha entry as case reports accumulated from the United States, Europe and Asia, with most cases beginning two to twelve weeks after starting the supplement and most resolving after stopping it. Several European food-safety agencies have issued cautions or restrictions since 2023, which in turn generated headlines that bounced back into the testosterone discussion.

What has not changed is the evidence base itself. No large, long trial has been published in the past two years that would move the needle in either direction. The newest ingredient is attention, not data. That matters because attention tends to flatten nuance: a 15 percent change inside the normal range becomes “boosted,” and a rare liver reaction becomes either “toxic” or “debunked,” depending on who is talking.

Reading the actual studies, which the next sections do, restores the proportion that the clips remove. The honest summary is a modest, consistent signal from small trials, a plausible mechanism, and a safety profile that is mostly reassuring with one exception serious enough to deserve its own section.

What is ashwagandha, and what are withanolides?

Ashwagandha is the root, and sometimes the leaf, of a small evergreen shrub, Withania somnifera, that grows across India, the Middle East and parts of Africa. Its Sanskrit name translates roughly as “smell of horse,” a reference to the odor of the fresh root and, in traditional framing, to strength.

The compounds that interest researchers are withanolides, a family of naturally occurring steroid-like molecules found in the plant; they are thought to be responsible for most of its measurable effects. Products are often labeled as “standardized” to a certain withanolide content, which simply means the manufacturer has tested each batch so that it contains a consistent amount. Two bottles that both say ashwagandha can still differ sharply: one may use root only, another root and leaf, one may be a water extract, another an alcohol extract, and the withanolide profile shifts with each choice.

This matters for the testosterone question because nearly all of the positive trials used a particular standardized root extract, taken daily for two to four months. Findings from one preparation do not automatically transfer to another, a point the NIH fact sheet makes explicitly.

Ashwagandha is usually described as an adaptogen, a marketing and herbal term for a substance claimed to help the body cope with stress; the word has no formal medical definition and no regulatory meaning. In the United States it is sold as a dietary supplement, which means the Food and Drug Administration does not review it for effectiveness before sale and does not approve it to treat any condition. The practical upshot: label claims about hormones, stamina or “male vitality” are claims the manufacturer chose to make, not claims an agency verified.

Does ashwagandha increase testosterone? What the evidence actually says

Testosterone is the main male sex hormone, produced mostly in the testicles, and it influences muscle, bone, red blood cells, mood and sexual function. The cleanest way to test whether a supplement changes it is a randomized controlled trial, a study in which participants are assigned by chance to the real product or a placebo, an inactive look-alike, so that neither expectation nor selection explains the result.

Ashwagandha has a handful of such trials, and they point the same way. Men given the standardized root extract for 8 to 16 weeks showed higher total testosterone than men given placebo, with the difference typically in the range of 10 to 20 percent. The populations were specific: men with infertility, men who were overweight and middle-aged with mild fatigue, and young men beginning a strength-training program.

How strong is that evidence? Graded honestly, it is low to moderate. The trials were randomized and placebo-controlled, which is the right design. But each enrolled fewer than 100 men, each ran for a few months at most, several were funded or supplied by the extract’s manufacturer, and nearly all used the same proprietary preparation, so there is little independent replication. None followed participants long enough to know whether the change persists, and none was designed to test whether a higher testosterone number translated into better health, mood or sexual function.

Observational data add little, and expert opinion from mainstream sources, including the NIH Office of Dietary Supplements and MedlinePlus, lands on “possible but insufficient evidence.” So the answer to the search question is a qualified yes: in small trials, ashwagandha modestly increased testosterone. Whether that is meaningful is a different question, and the one that matters.

Ashwagandha testosterone study results at a glance

The trials below are the ones most often cited, in clips and in the NIH fact sheet. Percentages are approximate and refer to the change in the ashwagandha group compared with placebo; exact figures vary with how each paper reported them.

Trial population	Duration	Testosterone finding	What else was measured
Men with infertility, India (2013)	3 months	About 17 percent increase	Higher sperm count and motility; no placebo arm in some analyses
Young men starting resistance training (2015)	8 weeks	About 15 percent greater rise than placebo	Larger strength and muscle-size gains, lower exercise-related muscle damage markers
Overweight men aged 40 to 70 with mild fatigue (2019)	16 weeks, crossover	About 15 percent increase	DHEA-S rose; cortisol, estradiol and fatigue scores did not differ meaningfully
Healthy adult men (2022)	8 weeks	Modest increase versus placebo	Self-reported stress and quality of life improved

Three patterns stand out. The direction is consistent, which is reassuring. The magnitude is modest; none of these studies reports anything resembling a doubling. And the populations were already under some kind of physiological strain, whether excess weight, infertility or a new training load, which fits the leading theory that the extract works, if it works, by dampening stress signals rather than by stimulating the testicles directly.

DHEA-S, mentioned in the 2019 trial, is a hormone made by the adrenal glands that the body can convert into testosterone and estrogen; a rise there hints that the adrenal side of the system is involved. The crossover design of that trial, where each man took both the extract and the placebo in separate periods, is a strength, since every participant served as his own control.

How could ashwagandha raise testosterone? The mechanisms being studied

No one has shown precisely how withanolides nudge testosterone, but three lines of research converge on a plausible story.

The first runs through cortisol, the body’s main stress hormone, released by the adrenal glands. Chronically high cortisol suppresses the signals the brain sends to the testicles. Several ashwagandha trials, mostly in people reporting chronic stress, found cortisol levels fell by roughly a quarter over two to three months compared with placebo. If cortisol drops, the brake on testosterone production may ease. This is the most widely cited mechanism, though notably the 2019 trial in older men found a testosterone rise without a clear cortisol change, so it cannot be the whole explanation.

The second involves luteinizing hormone, often shortened to LH, the pituitary hormone that tells the testicles to make testosterone. Small studies in infertile men reported higher LH alongside higher testosterone, suggesting the extract may act upstream in the brain rather than in the testicle itself.

The third is oxidative stress, the cell-level damage caused by reactive molecules when the body’s antioxidant defenses are overwhelmed. Sperm are unusually vulnerable to it, and the testicular cells that make testosterone are too. Laboratory and animal work show withanolides have antioxidant activity; the fertility trials reported lower markers of oxidative damage in semen.

Why does the mechanism matter to a reader rather than a researcher? Because it predicts who might respond. A stress-dampening effect would be expected to help most in men whose testosterone is being held down by poor sleep, overtraining, excess weight or psychological strain, and to do little in men whose levels are already optimal or whose low testosterone has a structural cause such as testicular damage or a pituitary problem. The trial populations fit that prediction. The influencer in the gym mirror, who may already be healthy, rested and lean, is the person least likely to see much.

What does a 15 percent testosterone rise actually mean for your body?

Numbers need a scale. A typical adult man’s total testosterone, measured on a morning blood test, falls somewhere between roughly 300 and 1,000 nanograms per deciliter, and most laboratories and urology guidelines treat values persistently below about 300 as low. A 15 percent increase for a man starting at 450 lands him near 520. He began in the normal range and he ends in the normal range.

Compare that with the body’s own daily swing. Testosterone peaks in the early morning and drifts down through the afternoon by 20 to 30 percent in younger men. Sleeping five hours a night for a single week lowered daytime testosterone by 10 to 15 percent in a small experimental study of healthy young men. Put plainly, the entire effect size seen in the ashwagandha trials is about the size of a bad week of sleep, or the difference between a 7 a.m. and a 3 p.m. blood draw.

That is not nothing, but it is not a transformation. Mainstream reviews, including Harvard Health’s overview of what testosterone does and does not do, make the point that symptoms such as low energy, low libido or weaker erections correlate only loosely with the number once it is inside the normal band. A man at 520 does not reliably feel different from a man at 450.

Where a modest shift might plausibly matter is at the margin: a man whose morning level hovers just under the threshold because of stress, weight and poor sleep. Even there, the trials cannot tell us whether the symptom improves, because they did not enroll men with diagnosed low testosterone and did not use symptom relief as a primary outcome. The honest reading is that the blood test moved; whether the person did is unknown.

Ashwagandha benefits for men beyond the testosterone number

Testosterone gets the headline, but the better-supported findings sit elsewhere, and they are worth knowing because they shape realistic expectations.

Stress and sleep have the largest body of evidence. Multiple randomized trials, mostly of adults reporting chronic stress or trouble sleeping, found lower scores on standardized stress and anxiety questionnaires and modest improvements in sleep quality over six to twelve weeks. The NIH fact sheet rates this as the area with the most consistent, if still preliminary, support. For a man whose low mood or flat libido is downstream of a stressful year, that may be the relevant effect, with or without any hormone change.

Strength and recovery come next. In the 2015 trial of young men starting a lifting program, those taking the extract gained more on bench press and leg extension and showed smaller rises in creatine kinase, a blood marker of muscle damage, after training. One trial is one trial, and the training stimulus itself did most of the work, but the direction was encouraging.

Sperm quality is the third area. Trials in men with infertility reported higher sperm counts, better motility and lower oxidative damage after about three months. These were small, and a higher count on a lab report is not the same as a pregnancy; fertility specialists consider the evidence promising rather than established.

What the research does not show is equally useful. There is no good trial evidence that ashwagandha improves erectile function, increases penis size, builds muscle without training, or “reverses” age-related decline. Claims in those directions are extrapolation, and some are simply invented. The pattern across the genuine findings is consistent: small, measurable, modest effects in people under some form of strain, over months rather than days.

Ashwagandha side effects and the liver question

For most adults in the trials, ashwagandha was well tolerated over a few months. The common complaints were drowsiness, stomach upset, loose stools and nausea, usually mild and usually settling. A few participants reported headaches or vivid dreams. Those are the side effects a reader is most likely to meet.

The liver is the exception that justifies caution. Hepatotoxicity, meaning injury to the liver caused by a substance, has been reported in dozens of published cases, and the NIH LiverTox database now classifies ashwagandha as a probable cause of clinically apparent liver injury. The typical picture is cholestatic, meaning bile flow is impaired: itching, dark urine, pale stools and yellowing of the skin or eyes appear two to twelve weeks after starting the supplement. Liver enzymes on blood tests rise, sometimes steeply. In nearly all reported cases, symptoms resolved within one to three months after the supplement was stopped, though a small number of people became seriously ill and at least one required intensive treatment.

Why this happens is unclear. It appears to be idiosyncratic, meaning an unpredictable individual reaction rather than a simple matter of taking too much, and it has occurred with products that tested as uncontaminated. No one can yet identify in advance who is susceptible.

How common is it? Unknown, and that uncertainty cuts both ways. Millions of people use ashwagandha each year and the published cases number in the dozens, so the absolute risk per user appears low. But supplement side effects are badly underreported, and the trials were far too small to detect a rare event. The sensible conclusion is that serious liver injury is rare, real, and not something a healthy-looking label can rule out.

Who should be cautious with ashwagandha

The trial participants were, by design, relatively healthy men. Several groups were excluded from every study, and for them the question is not whether ashwagandha raises testosterone but whether it is safe to take at all.

• Anyone with liver disease or a history of liver injury from a medicine or supplement. Given the case reports above, most hepatologists advise against it.
• People with thyroid conditions. Small studies and case reports suggest ashwagandha can raise thyroid hormone levels; that could worsen an overactive thyroid or interfere with treatment of an underactive one.
• People with autoimmune disease such as lupus, rheumatoid arthritis or multiple sclerosis. Laboratory work suggests the extract may stimulate immune activity, which is the opposite of what those conditions call for.
• Anyone with a hormone-sensitive condition, including prostate cancer, where a hormonal nudge in either direction deserves specialist input.
• Pregnant or breastfeeding women. Ashwagandha may cause uterine contractions; the NIH advises against use in pregnancy, and safety in breastfeeding is unstudied.
• People scheduled for surgery. Because the extract can slow the central nervous system, anesthesiologists generally ask patients to stop it at least two weeks before an operation.
• Anyone taking sedatives, thyroid medicine, immunosuppressants, or drugs for diabetes or blood pressure, covered in the next section.

Adolescents deserve a specific mention. The testosterone claim has an obvious pull for teenage boys, yet no trial has included anyone under 18, and the developing endocrine system is exactly where an unstudied hormonal effect is least welcome. Older men with a diagnosis of low testosterone sit in a different category: their condition has a workup and established treatments, and a supplement should be a conversation with the clinician managing it, never a substitute.

Ashwagandha interactions with common medicines

Supplements interact with medicines through the same biology as medicines interact with each other, and ashwagandha has several documented or theoretical overlaps. None is a reason to panic; all are reasons to tell the prescriber.

Sedation is the most practical. Ashwagandha has mild calming and sleep-promoting effects in trials, and combining it with benzodiazepines, sleep medicines, some antidepressants, opioid pain relievers or alcohol can add up to more drowsiness than either alone. For someone who drives for a living or operates machinery, that additive effect is not trivial.

Thyroid medicine is next. If the extract raises thyroid hormone output even slightly, a person on levothyroxine for an underactive thyroid may find their dose is suddenly too high, with palpitations, sweating, weight loss or anxiety as clues. Anyone on thyroid treatment who starts or stops ashwagandha should tell the clinician who monitors their blood tests.

Immunosuppressants, including those used after organ transplant or for autoimmune disease, may be opposed by the extract’s apparent immune-stimulating activity; the clinical significance is uncertain, but transplant teams usually advise avoiding herbal immune modulators altogether.

Diabetes and blood pressure medicines round out the list. Small trials suggest ashwagandha can lower blood sugar and blood pressure a little; stacked on top of prescribed treatment, that could tip someone into lightheadedness or low blood sugar. The effect is small enough that it rarely causes trouble, which is also why it often goes unnoticed until it does.

Two principles cover all of these. First, a supplement is a drug the regulator has not reviewed, so it belongs on the medication list the pharmacist and doctor see. Second, every decision to add, continue or stop belongs to the prescribing clinician, who can weigh the interaction against the reason the medicine was prescribed in the first place.

Common myths about ashwagandha and testosterone

Viral claims travel faster than trial tables. These are the ones that appear most often, set against what the research shows.

“It doubles your testosterone.” No published trial comes close. The consistent finding is an increase of roughly 10 to 20 percent, within the normal range, in specific groups of men. A claimed doubling, if the person measured anything at all, usually reflects comparing an afternoon draw with a morning one, or a sick-day value with a healthy one.

“It works like testosterone therapy, without the prescription.” Prescribed testosterone replaces the hormone directly and can take a man from clearly low to mid-normal. Ashwagandha, at best, lifts the body’s own production modestly. They are not the same category of intervention, and the next section lays out the differences.

“It’s natural, so it can’t hurt your liver.” Liver injury from botanical products is well documented, and ashwagandha now has its own entry in the NIH LiverTox database. Natural describes origin, not safety.

“The liver cases were all contaminated products.” Some reports did involve products of unknown quality, but several involved supplements that were tested and found to contain what the label said. The reaction appears to be an individual one.

“More is better.” Trials used one fixed daily amount of one extract for a set period; nothing shows a larger amount produces a larger hormone change, and the liver reports include people who took more than the label suggested.

“If it worked for him, it will work for you.” The mechanism points to stress reduction, so the men most likely to respond are those whose testosterone is being suppressed by strain. A rested, lean, low-stress man is the person with the least room to move.

None of these corrections turns ashwagandha into a villain. They simply return a modest supplement to its modest place.

Ashwagandha vs testosterone replacement therapy: not the same conversation

Readers often arrive at ashwagandha from the other direction: they suspect low testosterone, feel uneasy about prescription therapy, and hope a supplement is the gentle middle path. It helps to see how different the two really are.

Male hypogonadism, the medical term for the body producing too little testosterone, is a diagnosis, not a feeling. Mayo Clinic and urology guidelines describe it as persistently low morning testosterone on at least two separate blood tests, together with symptoms such as reduced libido, erectile difficulty, loss of muscle, fatigue or low mood. The workup also looks for a cause: pituitary problems, testicular injury, certain medicines, sleep apnea, obesity and a long list of others. Some of those causes are themselves treatable, and finding them is the point of the evaluation.

Testosterone replacement, prescribed as gels, injections, patches or pellets, is designed to bring a clearly low level into the normal range. It has well-characterized benefits and well-characterized risks, including effects on red blood cell count, fertility, the prostate and possibly the heart, which is why it requires monitoring and a prescriber. It is also not appropriate for men whose levels are normal, a point Harvard Health makes bluntly in its review of what the hormone does and does not do.

Ashwagandha, by contrast, has never been trialed in men diagnosed with hypogonadism, has an effect size that would not lift a clearly low level into the normal range, and is not approved to treat any condition. For a man with symptoms, taking it instead of getting tested risks delaying a diagnosis that may have a specific cause and a specific treatment.

The two can coexist in a conversation with a clinician. They cannot substitute for one another, and the choice between evaluation, treatment, lifestyle change or a supplement belongs to the man and his doctor, with a blood test on the table.

What moves testosterone more than any supplement

If the extract’s main lever is stress, the obvious question is what else pulls that lever, and how hard. The answer reframes the whole topic.

Sleep comes first. The experimental study that restricted healthy young men to five hours a night for a week measured a 10 to 15 percent fall in daytime testosterone, which is the entire ashwagandha effect erased in seven days. Untreated sleep apnea, common in men who snore and carry extra weight, suppresses the hormone further and is frequently the real diagnosis behind “low T” symptoms.

Body weight is second. Fat tissue contains an enzyme, aromatase, that converts testosterone into estrogen, so men with obesity tend to run lower levels. Observational studies and weight-loss trials consistently show testosterone rising as weight falls, with larger losses producing larger rises; the gains from meaningful weight reduction can exceed what any supplement trial has reported.

Resistance training is third, and here the 2015 ashwagandha trial is instructive. Both groups, extract and placebo, got stronger and both showed hormonal changes; the supplement added a margin on top of what lifting had already done. Regular strength work, two or three sessions a week, has its own well-documented effects on muscle, mood and metabolic health regardless of the hormone number.

Alcohol is fourth. Heavy drinking lowers testosterone directly and damages the liver, which is also the organ the supplement question keeps circling back to.

Chronic stress ties it together. Cortisol suppresses the system, and whatever reduces cortisol, whether sleep, exercise, counseling or a less punishing schedule, gets at the same mechanism the extract is thought to use. The point is not that supplements are useless. It is that a man who fixes sleep, weight, training and drinking has already captured most of what is available, and a man who has not will not supplement his way around it.

When to see a doctor about testosterone, ashwagandha or both

Some situations are worth a visit before the first capsule; others mean stopping and calling the same day. Both lists are short and worth remembering.

See a clinician before starting if you: have symptoms you suspect are low testosterone (low libido, erectile difficulty, unexplained fatigue, loss of muscle or body hair, low mood); have any liver, thyroid or autoimmune condition; take sedatives, thyroid medicine, immunosuppressants or treatment for diabetes or blood pressure; have a hormone-sensitive cancer; are under 18; or are trying to conceive and want fertility properly evaluated rather than guessed at. In each case the right first step is a conversation and, usually, a morning blood test, not a supplement.

Stop the supplement and seek care promptly if you develop any of these red flags:

• Yellowing of the skin or the whites of the eyes
• Dark urine, pale or clay-colored stools, or persistent itching
• Pain or tenderness under the right ribs, nausea or loss of appetite that lasts more than a day or two
• Palpitations, tremor, heat intolerance or unexplained weight loss, which can signal an overactive thyroid
• Severe drowsiness or confusion, especially if combined with alcohol or sedating medicines
• Rash, swelling of the face or lips, or trouble breathing, which are signs of an allergic reaction and warrant emergency care

Bring the bottle, or a photo of the label, to the appointment. The specific extract, the daily amount and the start date are exactly what a clinician needs to judge whether the supplement is the likely cause.

Every decision about continuing, stopping or combining ashwagandha with a prescribed medicine belongs to the clinician who knows your history. That is not caution for its own sake. It is the only way to tell a modest, well-tolerated supplement apart from the rare case where it is quietly doing harm.

Frequently asked questions

Does ashwagandha increase testosterone in healthy men?

Modestly, in the small trials that tested it. Men who were overweight, infertile or starting resistance training saw increases of about 10 to 20 percent over two to four months, within the normal range. The effect appears to come from lowering stress signals rather than stimulating the testicles directly, so healthy, rested, lean men may see little or no change.

Which ashwagandha testosterone study is the one everyone cites?

Usually the 2015 trial of young men beginning a strength-training program, who gained more muscle and showed about a 15 percent greater rise in testosterone than the placebo group over eight weeks. A 2019 crossover trial in overweight men aged 40 to 70 found a similar increase. Both were small and used the same proprietary root extract.

How long does ashwagandha take to affect testosterone?

The trials measured hormones after 8 to 16 weeks of daily use, and none reported earlier time points, so there is no evidence of a change within days. Anyone expecting a quick result is measuring normal day-to-day variation, which can swing testosterone by 20 to 30 percent between morning and afternoon on its own.

What are the ashwagandha benefits for men beyond hormones?

The most consistent trial findings are lower self-reported stress and anxiety and better sleep quality over six to twelve weeks. One trial found greater strength gains and less muscle-damage marker rise in men who were lifting weights, and small fertility studies found higher sperm counts and motility. Evidence for erectile function or muscle gain without training is lacking.

What are the ashwagandha side effects, and can it affect the liver?

Common side effects are drowsiness, stomach upset, loose stools and nausea, usually mild. Rarely, ashwagandha has caused liver injury, with itching, dark urine and yellowing of the skin or eyes appearing two to twelve weeks after starting; most cases resolved after stopping. The NIH LiverTox database lists it as a probable cause of liver injury.

Can ashwagandha replace testosterone therapy?

No. Prescribed testosterone replaces the hormone directly and can bring a clearly low level into the normal range, under medical monitoring. Ashwagandha has never been trialed in men with diagnosed low testosterone, and its modest effect would not lift a low level into normal. Men with symptoms should be tested and evaluated rather than self-treat with a supplement.

Is ashwagandha safe for teenagers who want higher testosterone?

There is no trial evidence in anyone under 18, and the developing endocrine system is where an unstudied hormonal effect is least welcome. Teenagers also commonly have normal testosterone and are responding to online claims rather than a medical problem. A clinician can address concerns about development, energy or body image without an untested supplement.

Does ashwagandha affect the thyroid?

Possibly. Small studies and case reports suggest it can raise thyroid hormone levels, which could worsen an overactive thyroid or shift the balance for someone on treatment for an underactive one. People with any thyroid condition, or taking thyroid medicine, should discuss ashwagandha with the clinician who monitors their blood tests before starting or stopping it.

Can I take ashwagandha with alcohol or sleep medicines?

Caution is advised. Ashwagandha has mild sedating effects in trials, and combining it with alcohol, benzodiazepines, sleep medicines, opioids or sedating antidepressants can add up to more drowsiness than either alone. Anyone taking prescribed sedating medicines should ask the prescriber or pharmacist before adding it, and it should appear on the medication list they see.

Does ashwagandha help male fertility?

Small trials in men with infertility reported higher sperm counts, better motility and lower oxidative damage in semen after about three months, alongside a modest rise in testosterone. These results are promising but preliminary, and a better lab report is not the same as a pregnancy. Couples trying to conceive benefit most from a proper fertility evaluation first.

References

• Ashwagandha, LiverTox: Clinical and Research Information on Drug-Induced Liver Injury (NIH)
• Ashwagandha, MedlinePlus Herbs and Supplements

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.