What the trials found
| Trial | Who | Length | Testosterone result |
|---|---|---|---|
| Ambiye, 2013 | 46 men with infertility | 90 days | Significant rise vs placebo |
| Wankhede, 2015 | 57 healthy men, average age about 28 | 8 weeks | Significant rise vs placebo |
| Lopresti, 2019 (crossover) | 57 men aged 40 to 70, overweight, mild fatigue | 8 weeks per period | 14.7% higher than placebo |
| Lopresti, 2019 (parallel) | Stressed adults; 19 men analyzed | 60 days | No significant difference vs placebo |
In the best-rated trial, the rise was in saliva testosterone, stayed within the normal range, and the authors reported it was not sustained 8 weeks after people stopped. The product maker funded that study. The authors called the sample small and said larger studies are needed.
How strong is the evidence?
Low. The trials are few and small, used different extracts and doses, and most had some risk-of-bias concerns. The 2021 review said ashwagandha and fenugreek had the most support among herbs tested, but that more research is needed before firm conclusions on benefit or safety. NCCIH describes the evidence as limited.
None of these trials studied men with diagnosed low testosterone (hypogonadism). If you have symptoms such as low sex drive, low energy or loss of muscle, get a morning testosterone blood test first. See also the total testosterone lab guide.
Safety: liver, thyroid, pregnancy and medicines
- Short-term use: generally well tolerated for up to about 3 months. Long-term safety is not known.
- Common side effects: loose stools, nausea, stomach upset and drowsiness.
- Liver injury: rare, but a number of cases have been linked to ashwagandha supplements.
- Thyroid: may affect thyroid function and interact with thyroid hormone medicine. NCCIH advises against it for people with thyroid or autoimmune conditions.
- Pregnancy and breastfeeding: avoid during pregnancy; NCCIH says not to use it while breastfeeding.
- Prostate cancer: because it may raise testosterone, people with hormone-sensitive prostate cancer should avoid it.
- Medicines: may interact with diabetes and blood pressure drugs, immunosuppressants, sedatives and anti-seizure medicines. Not recommended before surgery.
Stop taking ashwagandha and call a clinician if you develop yellow skin or eyes, dark urine, itching, belly pain, or unusual tiredness. Signs of an overactive thyroid, such as a racing heart, shakiness or unexplained weight loss, also need a check.
What to do instead of guessing
- Test before you treat: a morning total testosterone, repeated if low, plus related labs your clinician orders.
- Review sleep, body weight, activity, alcohol and stress with your clinician; they all matter for overall health.
- If you still want to try ashwagandha, tell your clinician, pick a third-party tested product, and stop after about 3 months unless your clinician advises otherwise.
- If your levels are truly low, talk with a clinician about the causes and options. See what is TRT.
Common questions
How much does ashwagandha raise testosterone?
In the best-rated trial, saliva testosterone was 14.7% higher than on placebo after 8 weeks, and it stayed within the normal range. Other trials differed in size and method.
How long does ashwagandha take to affect testosterone?
The trials that saw a rise ran 8 weeks to 90 days. In one trial, the authors reported the effect was not sustained 8 weeks after people stopped.
Is ashwagandha safe for men?
Most healthy adults tolerate it for up to about 3 months. Rare liver injury has been reported, and men with hormone-sensitive prostate cancer should avoid it.
Can ashwagandha replace TRT?
No. The trials didn't study men with diagnosed low testosterone, and the rises seen were modest. A clinician should evaluate low testosterone.
Does ashwagandha affect the thyroid?
It may. Ashwagandha can change thyroid function and interact with thyroid medicine, so people with thyroid conditions should talk with a clinician before using it.
Sources
- Ashwagandha: Is it helpful for stress, anxiety, or sleep? Fact Sheet for Health Professionals NIH Office of Dietary Supplements
- Ashwagandha National Center for Complementary and Integrative Health (NIH)
- Examining the Effects of Herbs on Testosterone Concentrations in Men: A Systematic Review (Smith et al., 2021) Advances in Nutrition
- A Randomized, Double-Blind, Placebo-Controlled, Crossover Study Examining the Hormonal and Vitality Effects of Ashwagandha in Aging, Overweight Males (Lopresti et al., 2019) American Journal of Men's Health
This guide is general information, not medical advice. It does not replace a visit with a licensed clinician. Gabriel membership is not health insurance.