Ashwagandha offers several well-studied benefits for men, with the strongest evidence supporting its effects on stress reduction, testosterone levels, fertility, and physical performance. Clinical trials consistently show measurable improvements across these areas, typically within one to three months of daily use at doses of 300 to 600 mg of a standardized root extract.
Effects on Testosterone
Multiple clinical trials have measured testosterone increases in men taking ashwagandha, with results ranging from about 11% to 22% depending on the dose, duration, and population studied. In one double-blind trial of healthy men aged 21 to 45, a 300 mg daily dose of root extract standardized to contain at least 5% withanolides produced a 17% increase in testosterone over two months. A separate trial in men aged 40 to 70 with symptoms of fatigue and low vitality found significant increases in both testosterone and DHEA-S (a precursor hormone) after four months of treatment.
Studies in infertile men using higher doses (5 grams of root powder daily) have shown even larger absolute increases, with testosterone rising by 0.85 to 1.43 ng/mL over three months. These gains were accompanied by favorable shifts in other reproductive hormones: luteinizing hormone increased by 11 to 21%, while prolactin decreased. The testosterone boost appears consistent across age groups and health profiles, though the size of the effect varies. Men with lower baseline levels or higher stress tend to see larger improvements.
Stress and Cortisol Reduction
Ashwagandha’s ability to lower cortisol, the body’s primary stress hormone, is one of its most reliable effects. In an eight-week randomized, placebo-controlled trial of chronically stressed adults, the ashwagandha group experienced a 23% reduction in morning cortisol levels. The placebo group, by comparison, saw a negligible 0.5% increase. This cortisol drop came alongside reductions in anxiety scores, resting pulse rate, blood pressure, and C-reactive protein (a marker of inflammation).
This matters for men specifically because chronically elevated cortisol suppresses testosterone production, disrupts sleep, promotes fat storage around the midsection, and impairs recovery from exercise. Lowering cortisol doesn’t just make you feel calmer. It creates hormonal conditions that support many of the other benefits ashwagandha is known for.
Fertility and Sperm Quality
For men with low sperm counts, the data is striking. In a pilot study of men with oligospermia (low sperm concentration), 90 days of ashwagandha root extract produced a 167% increase in sperm count, a 53% increase in semen volume, and a 57% increase in sperm motility. These are large improvements by any standard, taking average sperm concentration from about 9.6 million per milliliter to 25.6 million, which crosses the threshold considered normal for fertility.
These results have been replicated in similar populations, and the improvements appear to be driven partly by reduced oxidative stress in reproductive tissue and partly by the hormonal shifts described above. If you’re actively trying to conceive and dealing with a low sperm count, ashwagandha is one of the few supplements with meaningful clinical evidence behind it.
Muscle Strength and Body Composition
A randomized controlled trial of men engaged in resistance training found that ashwagandha supplementation significantly outperformed placebo on every strength and size metric measured. The ashwagandha group increased their bench press by an average of 46 kg over the study period, compared to 26.4 kg in the placebo group. Arm muscle size increased by 8.6 cm² versus 5.3 cm², and chest measurements grew by 3.3 cm versus 1.4 cm.
These differences are substantial, essentially representing a near-doubling of gains in some measures. The mechanism likely involves both the testosterone increase and improved recovery through lower cortisol and inflammation. Clinical trials on athletic performance have typically used doses in the range of 330 to 1,000 mg per day of standardized extract.
Sexual Desire and Function
A prospective, double-blind, placebo-controlled study in healthy men found that ashwagandha root extract produced significant improvements across nearly every domain of sexual function measured. Sexual desire scores increased by 61.9% over eight weeks in the supplement group, while the placebo group actually declined. The difference between groups was large enough to be considered clinically meaningful, not just statistically significant.
Beyond desire, men taking ashwagandha reported improvements in successful vaginal penetration, duration of intercourse, and total number of orgasms. By week eight, the overall sexual function score in the ashwagandha group was 15 points higher than placebo. Notably, these were healthy men without diagnosed sexual dysfunction, suggesting the benefits aren’t limited to men with existing problems.
How Long Before You Notice Results
Most men notice subtle effects within the first month, though the timeline varies by what you’re looking for. Stress and sleep improvements tend to show up earliest. Measurable changes in testosterone and sexual function typically appear by four to eight weeks in clinical trials. Strength and muscle gains require consistent training alongside supplementation and show up over eight to twelve weeks. Fertility improvements in the studies took a full 90 days to reach their peak numbers.
Dosage and What to Look For
Clinical trials have used doses ranging from 125 mg to 2,000 mg daily, but the sweet spot for most benefits appears to be 300 mg twice a day (600 mg total) of a standardized root extract. This dose has shown the best balance of effectiveness and safety across studies. Look for extracts standardized to contain a specific percentage of withanolides, the active compounds responsible for ashwagandha’s effects. KSM-66 and Sensoril are two widely studied branded extracts that meet this standard.
Root powder (the whole, non-extracted form) has been used in some studies at much higher doses of around 5 grams daily, but concentrated extracts are more practical and more commonly available as capsules.
Safety and Side Effects
In clinical trials lasting up to 24 weeks, ashwagandha root extract has been well tolerated with no serious adverse events reported. A 24-week study specifically designed to evaluate long-term safety found no clinically significant changes in laboratory values, supporting the conclusion that extended use at standard doses is safe for most people.
There are two notable cautions, though. First, ashwagandha can stimulate thyroid hormone production. There are case reports of thyrotoxicosis (overactive thyroid symptoms like weight loss, shakiness, and rapid heartbeat) in people taking ashwagandha, particularly at higher doses. If you have a thyroid condition or are taking thyroid medication, this interaction is worth discussing with your provider.
Second, while clinical trials have not shown liver enzyme elevations, a growing number of case reports since 2017 have linked ashwagandha to clinically apparent liver injury. The National Institutes of Health rates it as a “likely cause” of liver injury, though the occurrence is rare. Symptoms typically appear two to twelve weeks after starting supplementation, often presenting as jaundice and itching. Most cases resolve completely after stopping the supplement. However, rare severe outcomes have occurred in people with preexisting liver disease. Men with cirrhosis or chronic liver conditions should avoid ashwagandha entirely. For everyone else, choosing a reputable brand that undergoes third-party testing reduces the risk of contamination, which may account for some of the reported cases.