Ashwagandha and Testosterone: What the Clinical Trials Show

Key Takeaways

Multiple RCTs show ashwagandha raises total testosterone by 10 to 22 percent in men. The strongest evidence comes from KSM-66 at 600 mg/day over 8 to 16 weeks. The mechanism is indirect: ashwagandha lowers cortisol, which removes a brake on the hypothalamic-pituitary-gonadal axis and allows LH-driven testosterone production to recover. A 2021 systematic review of 32 herbal supplement trials named ashwagandha one of only two herbs with positive evidence for testosterone in men (Smith et al., 2021, Advances in Nutrition). The effect is clinically relevant for men with stress-suppressed or age-related low-normal testosterone. It will not push already-healthy levels into a supraphysiological range.

Does Ashwagandha Increase Testosterone?

It does, and the data is more consistent than for almost any other herbal supplement studied for this purpose. Across five placebo-controlled trials enrolling men aged 18–70, ashwagandha root extract produced statistically significant increases in serum testosterone compared to placebo. No trial showed testosterone going down.

That last point matters more than it sounds. The supplement industry is full of ingredients that show a bump in one study and nothing in the next. Ashwagandha's testosterone data has held up across different research teams, different countries, different age groups, and different extract formulations. When a finding replicates that many times in that many settings, it stops being a fluke and starts being a real biological signal.

The reason this keeps replicating is biological rather than pharmacological. Ashwagandha does not contain testosterone or anything structurally similar to it. It is not a hormone, a prohormone, or a SARM (for the full picture of what it does, see ashwagandha benefits). Instead it reduces cortisol, and cortisol and testosterone sit on opposite sides of a hormonal seesaw. Your body makes both from the same upstream precursor, pregnenolone. When your HPA axis is chronically activated by poor sleep, overtraining, job stress, or caloric restriction, the raw materials get shunted toward cortisol at the expense of testosterone. This is called the "pregnenolone steal" hypothesis, and while the term is debated among endocrinologists, the downstream effect is well documented: chronically stressed men have lower testosterone than their non-stressed counterparts, even after controlling for age and body fat.

What ashwagandha does is remove that bottleneck. With sustained cortisol reduction, the precursor pool becomes available for testosterone synthesis again. Your body does the rest. Ashwagandha is one of our best testosterone supplements for men for exactly this reason. This is why the testosterone increase is modest and proportional rather than dramatic. Ashwagandha is not injecting a signal, it is clearing a blockage.

What Do the Clinical Trials Actually Show?

Five controlled studies form the core evidence base. Each used a standardized root extract, each included a placebo arm, and each measured serum testosterone as a primary or secondary endpoint.

Chauhan et al., 2022 — the low-libido population

Fifty adult men with low sexual desire took 300 mg of ashwagandha root extract (KSM-66) twice daily for 8 weeks. Serum testosterone rose from an average of 402.8 to 474.8 ng/dL in the ashwagandha group, a mean increase of about 18 percent over placebo (p<0.0001), and the improvement in sexual wellbeing scores tracked alongside it. Sexual desire and overall wellbeing scores both improved. The trial was registered, randomized, and double-blinded (Chauhan et al., 2022).

What makes this trial especially relevant is the population. These were not men with diagnosed hypogonadism or fertility problems. They were otherwise healthy men who just noticed their sex drive had dropped. This describes a large portion of men in their thirties and forties who would never walk into an endocrinology clinic but who are searching "ashwagandha testosterone" online. The 17 percent rise in this group suggests the effect is not limited to clinical populations.

Wankhede et al., 2015 — the resistance-training population

Fifty-seven young men doing structured resistance training took 300 mg of KSM-66 twice daily for 8 weeks. The ashwagandha group gained an average of 96.2 ng/dL in testosterone versus only 18.0 ng/dL in the placebo group (p=0.004), which works out to roughly a 15 percent rise from baseline. Muscle strength, upper-body and lower-body, roughly doubled relative to the placebo group. Body fat percentage dropped more in the ashwagandha arm (Wankhede et al., 2015, JISSN).

The placebo group's testosterone actually declined by 2.6 percent over the same 8 weeks despite doing the same training program. That is not unusual, because heavy resistance training temporarily raises cortisol, which can suppress testosterone if recovery is inadequate. The ashwagandha group avoided that dip entirely, likely because the cortisol-blunting effect of KSM-66 protected their hormonal recovery between sessions. For men who train hard, this is the trial that matters most: the question is not only whether ashwagandha raises testosterone on its own, but whether it protects against the training-induced suppression that can undermine your gains. For the broader picture on muscle and performance, see ashwagandha for men.

Lopresti et al., 2019 — aging and overweight men

This crossover RCT enrolled 36 men aged 40–70 who were overweight. Each took Shoden ashwagandha extract (delivered as beads providing 21 mg of withanolide glycosides per day) or placebo for 16 weeks, then switched. Salivary testosterone increased 14.7 percent during the ashwagandha phase and DHEA-S rose 18 percent, while fatigue declined (Lopresti et al., 2019, Am J Men’s Health).

The crossover design is what makes this trial hard to dismiss. Every participant served as his own control, with the same body, lifestyle, and genetics, just ashwagandha versus placebo in different periods. That eliminates the biggest source of noise in supplement research: individual variation. When the same man shows higher testosterone during the ashwagandha phase and lower testosterone during placebo, the signal is about as clean as a supplement trial gets.

The 18 percent DHEA-S increase deserves its own mention. DHEA-S is an adrenal precursor that sits upstream of both testosterone and estrogen. An increase suggests ashwagandha may be doing two things at once: disinhibiting testicular testosterone production and nudging the adrenal contribution upward. For men over 50, whose adrenal androgen output declines more sharply than testicular output, this could be the more relevant pathway.

Salve et al., 2025 — long-term safety with hormone data

A 12-month prospective observational study of KSM-66 at 600 mg/day in healthy adults found that both free and total testosterone increased significantly over the course of a year, with no adverse hepatic, renal, or thyroid effects. This is the longest published safety dataset for ashwagandha and the only one tracking testosterone beyond 16 weeks (Salve et al., 2025, Phytotherapy Research).

The usual concern with long-term adaptogen use is that the body might adapt and the effect might fade. The Salve data does not support that worry, since testosterone kept climbing through month 12 rather than plateauing at month 3. The study was observational rather than placebo-controlled, so it carries less weight than the RCTs above. But for the question "will this keep working if I take it for a year," it is the only data point that exists, and it says yes.

Khanna et al., 2026 — sexual health and semen parameters

The most recent trial enrolled 76 healthy men aged 30–50 in a double-blind RCT. Eight weeks of ashwagandha root extract improved semen volume, sperm count, and motility alongside gains in erectile function and sexual desire scores. While testosterone was not the primary endpoint, the hormonal and semen data are consistent with the HPG-axis recovery pattern seen in earlier trials (Khanna et al., 2026, Frontiers in Reproductive Health).

This trial bridges two conversations that are often treated separately: testosterone and fertility. Improved semen parameters (count, motility, morphology) require functional Leydig and Sertoli cells, both of which depend on adequate testosterone and FSH signaling. When ashwagandha improves semen quality and erectile function in the same trial, it is not producing two independent effects. It is showing one upstream improvement, HPG-axis recovery, manifesting in two downstream outcomes. For men whose primary concern is fertility rather than testosterone numbers per se, the data here is directly applicable. For a deeper look at the libido-specific evidence, we have a separate article.

What the trials tell us collectively

Pull back from individual studies and a pattern emerges. Every trial that measured both cortisol and testosterone found them moving in opposite directions, with cortisol down and testosterone up. The magnitude of the testosterone increase tracks roughly with the magnitude of the cortisol decrease and the duration of supplementation. The populations ranged from young gym-goers to overweight men in their sixties, and the direction of the effect was the same in every case. That consistency across demographics is what separates ashwagandha from most of the testosterone-boosting supplement market, where a single positive trial in a narrow population gets extrapolated far beyond what the data supports.

It is also worth noting what the trials did not show. None reported significant adverse events attributable to ashwagandha. None showed testosterone crashing after discontinuation (though only the Salve study tracked beyond 16 weeks). And none showed the kind of supraphysiological testosterone spikes that would suggest the herb is acting as an anabolic agent. The profile is one of normalization, bringing suppressed levels back toward their physiological ceiling, rather than pharmacological enhancement.

How Much Does Testosterone Actually Rise?

Expect a 10–22 percent increase in total testosterone from baseline, depending on your starting point and stress levels. That translates to roughly 50–120 ng/dL in absolute terms for most men.

To put that in context: normal total testosterone in adult men ranges from about 300 to 1,000 ng/dL. A man sitting at 400 ng/dL who sees a 17 percent rise lands around 468. That shifts him from the low end of normal into the mid-range. A man at 550 who gets the same 17 percent bump reaches 644. Neither of those is going to turn you into a different person, but both may be enough to notice a difference in energy, recovery, and how you feel in the mornings.

Contrast that with testosterone replacement therapy, which typically targets 500–900 ng/dL regardless of where you start and delivers the hormone directly. Ashwagandha cannot do that. It removes an obstacle rather than injecting a payload. The ceiling on your testosterone is still set by your genetics, age, and lifestyle. Ashwagandha simply helps your body reach closer to its own ceiling instead of sitting 10–20 percent below it because of chronic stress.

The largest percentage increases in the literature come from infertile men with severely suppressed baseline levels. Claims of a "534 percent testosterone increase" trace back to the Ahmad 2010 trial in oligospermic men whose starting testosterone was pathologically low, some under 100 ng/dL. Going from 80 to 500 is a large percentage, but it says nothing about what happens when you start at a normal level. For men’s health outcomes more broadly, the 10 to 22 percent range is the honest expectation, and it is worth being realistic about it.

One more nuance: free testosterone may matter more than total. Total testosterone includes the fraction bound to SHBG (sex hormone-binding globulin), which is biologically inactive. The Lopresti trial showed DHEA-S increasing alongside total testosterone, which suggests more precursor is available for conversion, potentially affecting free testosterone disproportionately. The Salve 2025 study confirmed that free testosterone rose alongside total. If you are testing, ask for both.

How Does Ashwagandha Raise Testosterone?

The primary mechanism is cortisol-mediated HPG axis disinhibition. There is a secondary antioxidant pathway that may protect Leydig cells directly.

Think of testosterone production as a factory with a three-step supply chain. Your hypothalamus releases GnRH (gonadotropin-releasing hormone), which tells the pituitary to release LH (luteinizing hormone), which tells the Leydig cells in the testes to produce testosterone. Under normal conditions, this chain runs smoothly and self-regulates through feedback loops.

Chronic cortisol elevation disrupts this chain at every level. At the hypothalamus, cortisol suppresses GnRH pulsatility, meaning the "produce testosterone" signal fires less often. At the pituitary, cortisol blunts sensitivity to GnRH, so even the signals that do get through produce less LH. At the testes, cortisol directly impairs Leydig cell function and competes for the same enzymatic pathways that convert cholesterol into testosterone. The result is a coordinated suppression of testosterone output that can persist for as long as the stress does.

Ashwagandha's well-documented cortisol reduction (a 2025 meta-analysis of 15 RCTs with 873 participants measured an average drop of 2.36 µg/dL) removes this brake at all three levels at once and allows normal testosterone production to resume (Bachour et al., 2025, BJPsych Open). The largest analysis to date, a 2026 systematic review and meta-analysis of 23 trials covering 1,706 participants, confirmed a significant cortisol reduction and found dose-response effects tied to withanolide content (Fornalik et al., 2026, Planta Medica). That is why the testosterone increase correlates with the cortisol decrease in every trial that measured both, which tells us the two effects are mechanistically linked rather than coincidental.

The antioxidant pathway is less well established in humans but robust in preclinical data. Withanolides, the active compounds in ashwagandha, scavenge reactive oxygen species in testicular tissue. Oxidative stress is one of the known destroyers of Leydig cell steroidogenic capacity, and it accumulates with age, environmental toxin exposure, and poor diet. A 2025 narrative review spanning preclinical and clinical data concluded that ashwagandha modulates the HPG axis in men primarily through cortisol lowering, with antioxidant protection of gonadal tissue as a contributing factor (Vollmer & Brendler, 2026, Phytotherapy Research).

There is a practical implication here. If your testosterone is low because of a pituitary tumor, primary hypogonadism, or a genetic condition, the HPG axis is broken in a way that cortisol reduction cannot fix. Ashwagandha works specifically on the stress-mediated suppression pathway. That is a large group of men, arguably the largest group walking around with suboptimal testosterone, but it is not every man with low T.

How Much Ashwagandha Per Day for Testosterone?

600 mg of KSM-66 per day is the dose used in the strongest testosterone trials. Split it as 300 mg morning and 300 mg evening, taken with food.

The Chauhan and Wankhede studies both used 300 mg twice daily of KSM-66 (standardized to 5 percent withanolides). Lopresti used Shoden delivered as beads providing 21 mg of withanolide glycosides per day, a smaller absolute dose but a high-concentration extract, keeping the active-compound exposure in a comparable range. The bottom line: use a standardized extract at the dose validated in trials.

Why split the dose? Withanolides have a relatively short half-life, and splitting into two doses maintains more consistent blood levels throughout the day. Taking it with food improves absorption, because withanolides are lipophilic (fat-soluble) and a meal with some fat helps your gut absorb them. Taking ashwagandha on an empty stomach is not dangerous, but you may absorb less and you are more likely to experience mild stomach discomfort.

A common mistake is taking generic ashwagandha root powder at 1–3 grams per day and expecting the same results as the trials. Raw powder has not been tested for testosterone in controlled settings, and the withanolide content can vary enormously between batches, sometimes by a factor of ten. A gram of random powder might deliver 5 mg of withanolides or 50 mg, and you have no way to know which. Standardized extracts exist precisely to solve this problem. For a complete dose guide covering different goals, see ashwagandha dosage.

How Long Does It Take to See Testosterone Changes?

Plan on a minimum of 8 weeks. Most trials measured testosterone at 8, 12, or 16 weeks, and none has shown a meaningful testosterone shift before week 8.

This timeline follows from the mechanism, and understanding it helps set realistic expectations. Cortisol levels begin dropping within 2 to 4 weeks of starting ashwagandha, and you may notice better sleep, less anxiety, or calmer reactions to stress in that window. But the downstream effect on LH pulsatility and Leydig cell output takes additional time. The hypothalamus needs to register the lower cortisol environment, increase GnRH output, and then the pituitary and testes need to respond. That cascade takes weeks rather than days.

A rough timeline based on the trial data and the underlying biology looks like this. Weeks 1–3: cortisol begins declining, subjective stress improves, sleep quality may improve. Weeks 4–6: DHEA-S may start rising as the adrenal glands shift precursor allocation. Weeks 8–12: serum testosterone reaches a measurably higher level versus baseline. Months 3–12: based on the Salve 2025 data, the effect may continue compounding rather than plateauing.

If you are tracking, the practical protocol is straightforward. Get a baseline total and free testosterone blood draw before you start, taken in the morning before 10 AM, since testosterone peaks in the morning and drops through the day. Then retest at 10–12 weeks using the same lab and the same time of day. Testing at week 4 gives you noise rather than signal, because you will see day-to-day fluctuation instead of a real trend. For timing and how the timeline compares across other outcomes like anxiety and sleep, see how long ashwagandha takes to work.

Does Ashwagandha Increase Testosterone in Women?

The data is thin and the context is different. One trial in perimenopausal women showed increased estradiol and decreased LH, not increased testosterone. Do not extrapolate men’s testosterone data to women.

Women produce testosterone in much smaller quantities, roughly 15 to 70 ng/dL compared to 300 to 1,000 in men, and through different pathways. In women, testosterone comes primarily from the adrenal glands and ovaries, not from Leydig cells (which women do not have). The hormonal regulation is different, the feedback loops are different, and the clinical significance of a 15 percent change is different.

Ashwagandha’s cortisol reduction could theoretically affect DHEA-S and downstream androgens in women, but no RCT has specifically measured testosterone as an endpoint in a female population. The Gopal 2021 trial in perimenopausal women found hormonal shifts toward estradiol rather than testosterone. This fits the idea that ashwagandha supports whichever hormonal pathway is most suppressed by stress, and in perimenopausal women that pathway runs toward estrogen. A 2026 review of ashwagandha in women’s hormonal health reached the same conclusion, noting that the androgen effect appears sex-specific and does not elevate testosterone in women the way it does in male study groups (Namysł et al., 2026, Cureus).

For women concerned about excess androgens (as in PCOS), the cortisol-reduction mechanism should theoretically not worsen hyperandrogenism, but there is no trial data to confirm that. Consult your prescriber. For women-specific evidence across all outcomes, see ashwagandha for women.

KSM-66 vs Sensoril vs Generic Ashwagandha for Testosterone

All testosterone trial data comes from KSM-66 or Shoden extracts. Sensoril and generic powders have not been tested for testosterone in controlled human studies.

This is not a minor distinction. Ashwagandha extracts are not interchangeable. They differ in which part of the plant is used, how the active compounds are extracted, and what concentration of withanolides ends up in the final product. Those differences determine whether you are taking something that has been validated for your goal or something that has not.

KSM-66 is a full-spectrum root-only extract standardized to 5 percent withanolides, made using a water-based extraction process. It has the most published RCTs of any ashwagandha extract, including the Chauhan, Wankhede, and Salve testosterone studies above. Shoden is a high-concentration root-and-leaf extract standardized to a much higher percentage of withanolide glycosides. It was used in the Lopresti trial as beads delivering 21 mg of withanolide glycosides per day, a smaller absolute dose because the concentration is higher per milligram.

Sensoril uses a different extraction process and is standardized to 10 percent withanolides by total alkaloid weight. It has strong published data for cortisol reduction and anxiety, but no published RCT with testosterone as an endpoint. Could it raise testosterone via the same cortisol mechanism? Theoretically, yes. But "theoretically yes" is not the same as "demonstrated in a trial," and if testosterone is your specific goal, you want the extract that has actually been tested for it.

Generic ashwagandha root powder sold in bulk has no standardization at all, meaning the withanolide content varies widely between brands and even between batches of the same brand. You are essentially guessing at your dose. For testosterone specifically, KSM-66 at 600 mg/day has the most replication across independent research groups. This is the extract we use in our ashwagandha formula. For a deeper comparison, see KSM-66 vs regular ashwagandha extract, and for product picks, our roundup of the best KSM-66 ashwagandha supplements.

Who Should Not Rely on Ashwagandha for Testosterone

Ashwagandha is not a replacement for TRT in clinically hypogonadal men, and it will not override lifestyle factors that are actively suppressing testosterone.

If your total testosterone is below 300 ng/dL on two morning blood draws, that is clinical hypogonadism and warrants a conversation with an endocrinologist, not a supplement. Ashwagandha’s 10–22 percent uplift does not close a gap that large. Going from 250 to 300 leaves you at the bottom of the reference range with symptoms likely unchanged. That is a situation where testosterone replacement therapy may be medically appropriate, and where relying on a supplement instead simply delays proper care.

Similarly, lifestyle factors that are actively suppressing testosterone will overwhelm anything ashwagandha can do. The big four are sleep deprivation (less than 6 hours drops testosterone by 10–15 percent on its own), chronic caloric deficit (undereating for extended periods signals your body to shut down reproduction), excessive alcohol (more than two drinks daily suppresses LH directly), and obesity (adipose tissue converts testosterone to estrogen via aromatase). Fix the inputs first. Ashwagandha works best when it is removing the stress-mediated suppression on top of a reasonably functional baseline, rather than compensating for a system that is under assault from five directions.

Men on thyroid medication should consult their prescriber before adding ashwagandha, since it can shift thyroid hormone levels. The Brendler 2025 review reported that ashwagandha can elevate T3 and T4 in hypothyroid contexts, which may interact with levothyroxine dosing. The same applies to anyone on immunosuppressants or androgen-modulating drugs like clomiphene or anastrozole. For a full list of interactions, see ashwagandha side effects.

What Else Supports Testosterone Alongside Ashwagandha

Ashwagandha handles the cortisol side of the equation. The other major levers, which are sleep, training, body composition, and micronutrients, are things you control directly.

Sleep is the single largest non-pharmaceutical factor in testosterone production. Testosterone is synthesized primarily during deep sleep, and restricting sleep to 5 hours per night for one week drops testosterone by 10–15 percent in young healthy men. That is roughly the same magnitude as the increase ashwagandha provides. If you are taking ashwagandha while sleeping poorly, the supplement is fighting the sleep deficit to a draw rather than building on a solid base.

Resistance training, particularly compound movements like squats, deadlifts, and rows, acutely stimulates testosterone and growth hormone. The Wankhede trial showed that ashwagandha plus resistance training produced larger testosterone and strength gains than either alone. For programming, see our best supplement stack for muscle growth. Zinc (found in red meat, oysters, and pumpkin seeds) and vitamin D are the two micronutrients with the clearest evidence for supporting testosterone in men who are deficient in them. Correcting a zinc or vitamin D deficiency will not produce dramatic testosterone surges in someone who is already replete, but it removes a limitation that keeps your hormonal system from working at full capacity.

The ideal stack, if you want to call it that, is not five supplements. It is eight hours of sleep, three to four resistance sessions per week, adequate calories and protein, sufficient zinc and vitamin D, and ashwagandha to handle the cortisol suppression that even a well-structured lifestyle cannot fully prevent in a stressful world. If stress is your main driver, our best supplements for stress guide covers the wider toolkit.

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