Ashwagandha does appear to increase testosterone in men, though the effect is moderate. Across multiple placebo-controlled trials, men taking ashwagandha saw testosterone increases ranging from about 15% to 22% over 8 to 12 weeks. A meta-analysis pooling results from several studies found an average increase of roughly 146 ng/dL in male participants. That’s meaningful, but it won’t transform someone with clinically low testosterone into the normal range on its own.
What the Clinical Trials Actually Show
The strongest evidence comes from a handful of randomized, placebo-controlled trials, each testing different populations. In a study of overweight men aged 40 to 70 with mild fatigue, eight weeks of ashwagandha extract produced a 14.7% greater increase in testosterone compared to placebo. The same study found an 18% increase in DHEA-S, a precursor hormone the body converts into both testosterone and estrogen.
A separate trial looked at young men (ages 18 to 50) doing resistance training. Those taking 600 mg of ashwagandha root extract daily for eight weeks saw their serum testosterone rise by about 96 ng/dL, compared to just 18 ng/dL in the placebo group. That difference was statistically significant. The ashwagandha group also gained more muscle strength on bench press and leg extension exercises.
In men with low sperm counts, 675 mg daily for 90 days raised testosterone by 17%, from an average of 4.45 ng/mL to 5.22 ng/mL. That study also showed dramatic improvements in sperm health: a 167% increase in sperm concentration, a 53% increase in semen volume, and a 57% increase in sperm motility. For men dealing with fertility issues, those numbers are more striking than the testosterone bump alone.
How Long It Takes to Work
Most trials measured testosterone at the 8-week mark, and that’s where statistically significant changes consistently showed up. The fertility study ran for 12 weeks (90 days). There’s no reliable data showing meaningful testosterone changes in the first week or two. If you start taking ashwagandha expecting a quick hormonal shift, you’ll likely need to wait at least two months before blood work would reflect a difference.
How It Likely Works
Ashwagandha is classified as an adaptogen, meaning it helps the body manage stress. Its active compounds (called withanolides) are thought to lower cortisol, the body’s primary stress hormone. Cortisol and testosterone have an inverse relationship: when cortisol stays chronically elevated, it suppresses the hormonal signaling chain that triggers testosterone production. By dialing down that stress response, ashwagandha may remove a brake on testosterone output rather than directly stimulating it.
This mechanism matters for setting expectations. If your cortisol levels are already low and your stress is well managed, ashwagandha may not move the needle much. The men who seem to benefit most in studies are those under physical or psychological stress, carrying extra weight, or dealing with fatigue. Healthy young men with already-optimal hormone levels have less room for improvement.
Dosages Used in Studies
The effective doses varied by formulation. The resistance training study used 600 mg per day of root extract (split into two 300 mg doses). The fertility study used 675 mg per day (split into three doses). The aging male study used a concentrated extract delivering just 21 mg of withanolide glycosides per day, which is a much smaller raw dose but a more refined preparation.
This variation highlights something important: not all ashwagandha supplements are equivalent. Different brands use different extraction methods, different parts of the plant, and different standardizations of the active withanolide compounds. The dose on the label matters less than the concentration of withanolides it delivers. Most commercially available supplements fall in the 300 to 600 mg range of root extract, which aligns with the doses shown to work in trials.
Effects on Women
The research on ashwagandha and testosterone in women is much thinner. One pilot study exploring sexual function in women hypothesized that ashwagandha might offset age-related testosterone decline, since women’s testosterone levels naturally drop over time and low levels are linked to reduced sexual desire. The researchers suggested ashwagandha could raise testosterone in women similarly to men, but the study focused on sexual function outcomes rather than directly measuring hormone changes. Notably, it did not find improvements in sexual desire despite other benefits. There isn’t enough controlled data to say whether ashwagandha reliably raises testosterone in women or by how much.
Safety Concerns Worth Knowing
Ashwagandha is generally well tolerated in the doses used in research, but it’s not risk-free. Australia’s Therapeutic Goods Administration issued a safety alert after receiving reports of liver problems in people taking ashwagandha products. Of 12 reports reviewed through early 2024, seven had enough detail to suggest the liver injury was plausibly caused by the supplement. The risk is considered very rare, but liver injury can be severe when it occurs.
Symptoms to watch for include yellowing of the skin or eyes, dark urine, nausea, unusual tiredness, and abdominal pain. Anyone with existing or past liver problems should avoid ashwagandha. The supplement may also increase thyroid hormone levels, which could be problematic for people with hyperthyroidism or those on thyroid medication. The NIH also notes that because ashwagandha can raise testosterone, it may not be safe for men with hormone-sensitive prostate cancer.
Some users report gastrointestinal symptoms, particularly at higher doses or on an empty stomach. These tend to be mild and temporary, but sudden or severe stomach issues are a signal to stop.
Putting the Numbers in Perspective
A 15% testosterone increase sounds impressive in a headline, but context matters. For a man with a total testosterone of 400 ng/dL, a 15% bump brings him to about 460 ng/dL. That’s a real change, but both numbers fall within the normal range for adult men (roughly 300 to 1,000 ng/dL). Ashwagandha is not comparable to testosterone replacement therapy, which can increase levels by several hundred percent. It’s more accurately described as a nudge, particularly useful for men whose levels are on the lower end of normal or who are under chronic stress that may be suppressing their natural production.
The strongest practical benefits in the research weren’t the testosterone numbers themselves but the downstream effects: better sperm parameters in infertile men, greater strength gains during resistance training, and improved recovery. Whether those outcomes were driven purely by higher testosterone or by ashwagandha’s broader effects on stress, inflammation, and sleep is hard to untangle. For most people considering it, the real question isn’t whether the testosterone number goes up on a lab report, but whether they feel or perform noticeably better. On that front, the evidence is promising but not overwhelming.