Ashwagandha does appear to increase testosterone in men, though the effect is modest and most pronounced in specific groups: men who are stressed, overweight, aging, or dealing with fertility issues. Several clinical trials have found statistically significant increases in testosterone after 8 to 12 weeks of daily supplementation, but the bump is relatively small compared to what you’d see from medical testosterone therapy. If you’re a healthy young man with normal hormone levels, the effect may be barely noticeable.
How Ashwagandha Affects Testosterone
Ashwagandha likely raises testosterone through two separate pathways. The first involves cortisol, your body’s main stress hormone. Cortisol and testosterone have an inverse relationship: when cortisol stays chronically elevated, it suppresses the hormonal signaling chain that tells your testes to produce testosterone. Multiple trials have shown ashwagandha lowers cortisol levels, which may remove that brake on testosterone production.
The second pathway is more direct. Lab and animal studies suggest ashwagandha stimulates the release of gonadotropin-releasing hormone (GnRH), the signal your brain sends to kick-start testosterone production in the testes. By boosting that signal, ashwagandha may increase testosterone output at the source. It also raises levels of DHEA, a precursor hormone that your body converts into testosterone.
This dual mechanism helps explain why the testosterone effect is strongest in men under physical or psychological stress. If your cortisol is already low and your hormonal signaling is working normally, there’s less room for ashwagandha to make a difference.
What the Clinical Trials Show
Most studies testing ashwagandha and testosterone have used doses between 300 mg and 600 mg of root extract daily, taken for 8 to 16 weeks. The populations studied matter a lot when interpreting results. Trials in overweight, aging men and in men with low sperm counts tend to show the clearest testosterone increases. Trials in young, healthy, physically active men show smaller or sometimes insignificant changes.
A randomized, double-blind, placebo-controlled crossover study published in the American Journal of Men’s Health tested ashwagandha in aging, overweight males and found increases in both DHEA and testosterone compared to placebo. The increases were statistically significant but not dramatic. This pattern repeats across the literature: real but moderate effects, typically in the range of a 10% to 25% increase over baseline depending on the population studied. For context, that might mean going from, say, 400 ng/dL to 450 or 500 ng/dL. Meaningful, but not transformative.
Most participants in these trials needed at least 8 weeks before measurable hormonal changes appeared. The 90-day mark is where results tend to be most robust, suggesting ashwagandha works gradually rather than producing a quick spike.
Effects on Male Fertility
The strongest evidence for ashwagandha’s reproductive benefits comes from men with low sperm counts. A pilot study in men with oligospermia (clinically low sperm concentration) found striking improvements after 90 days of ashwagandha root extract. Sperm count increased by 167%, rising from about 9.6 million per milliliter to 25.6 million. Semen volume increased by 53%, and sperm motility improved by 57%. All of these changes were highly statistically significant.
These are impressive numbers, but they came from men who started with abnormally low values. The results suggest ashwagandha may help restore reproductive function in men whose systems are underperforming, rather than supercharging already-normal fertility. If you’re exploring ashwagandha because you and a partner are trying to conceive, these findings are encouraging, though a single pilot study isn’t definitive proof.
Will It Help With Muscle Building?
This is probably the real question behind many searches on this topic. The logic goes: more testosterone equals more muscle. And while that’s true at the extremes (testosterone replacement therapy does increase muscle mass), the modest testosterone bump from ashwagandha is unlikely to produce dramatic physique changes on its own.
That said, ashwagandha may still support training results through other mechanisms. Its cortisol-lowering effect can improve recovery, sleep quality, and stress resilience, all of which contribute to better workouts and muscle growth over time. Some resistance training studies have reported small improvements in strength and body composition with ashwagandha supplementation, but separating the testosterone effect from the stress-reduction effect is difficult. Think of it as a useful supporting supplement rather than a muscle-building shortcut.
Thyroid Risks Worth Knowing About
Ashwagandha doesn’t just affect testosterone. It also stimulates the thyroid gland, increasing production and release of thyroid hormones T3 and T4. In one mouse study, T4 levels rose by approximately 111% after 20 days of supplementation. In humans, case reports have documented thyrotoxicosis (dangerously high thyroid hormone levels) linked to ashwagandha use, including at least one case that triggered a rapid heart rhythm requiring hospitalization.
Some commercially available ashwagandha supplements have been found to contain amounts of T3 and T4 that exceed the doses used to treat hypothyroidism. If you have a thyroid condition, are taking thyroid medication, or have a family history of thyroid disease, this is a real concern. Even without a known thyroid condition, monitoring how you feel on ashwagandha is important. Symptoms like rapid heartbeat, unexplained weight loss, tremors, or feeling wired and anxious could indicate your thyroid is being overstimulated.
Liver Safety Concerns
A growing number of case reports from the U.S., Japan, Iceland, and India have documented liver injury in people taking ashwagandha supplements. The pattern typically involves jaundice (yellowing of the skin and eyes), elevated liver enzymes, and in some cases, acute liver damage requiring hospitalization.
One reported case involved a man who took ashwagandha at the recommended dose for over a year without problems, then switched brands and developed acute liver injury within 20 days. Another case involved a woman who developed cholestatic hepatitis (a specific type of liver inflammation that blocks bile flow) with tissue death confirmed on biopsy. In a series of five patients from Iceland, all developed jaundice and drug-induced liver damage, which took eight months to resolve after stopping the supplement.
These cases are rare relative to the millions of people who take ashwagandha, but they’re worth knowing about. Liver injury from supplements can be unpredictable, and quality control varies widely between brands. If you develop nausea, dark urine, abdominal pain, or yellowing skin while taking ashwagandha, stop immediately.
Who Benefits Most
The evidence points to a clear pattern: ashwagandha’s testosterone-boosting effect is most relevant for men who are chronically stressed, overweight, over 40, or experiencing fertility problems. These are the groups where cortisol tends to be elevated and hormonal signaling tends to be suppressed, giving ashwagandha the most room to work.
If you’re a healthy man in your 20s with normal testosterone levels and low stress, you’re unlikely to see a meaningful hormonal change. You may still benefit from ashwagandha’s effects on sleep, anxiety, and recovery, but testosterone probably won’t be the mechanism. For women, the research is much thinner. Most clinical trials have been conducted exclusively in men, and the testosterone-producing pathway through the testes (via GnRH stimulation) is obviously male-specific. Women produce testosterone in smaller amounts through different mechanisms, and whether ashwagandha meaningfully affects those levels remains unclear.