Ashwagandha as a Testosterone Booster: What the Studies Show

Ashwagandha can modestly raise testosterone in some men, but the effect is smaller and less certain than most supplement ads suggest. As an ashwagandha testosterone booster, the best trials show increases of roughly 15% over placebo after eight weeks, mostly in small studies, often funded or supplied by extract makers.

This article focuses only on testosterone. For stress, sleep and general use, see our broader guide to ashwagandha for men.

Key takeaways

• Best trials show about a 15% rise in testosterone
• Most studies used 600 mg/day of root extract for 8 weeks
• Studies are small and often industry-supported
• Rare liver injury and thyroid effects are real risks

Does ashwagandha work as a testosterone booster?

A 2021 systematic review in Advances in Nutrition looked at 32 randomized trials of 13 herbs and found that ashwagandha was one of only two with positive effects on testosterone in men (the other was fenugreek). The authors also stressed the limits: small samples, varied doses and extracts, and mostly young, healthy volunteers rather than men with diagnosed low testosterone.

So the short answer is yes, ashwagandha is one of the better-supported herbal testosterone boosters, but “better-supported” is a low bar in this field.

What the main studies show

Young men starting weight training (2015)

In a trial of 57 untrained men aged 18 to 50, 300 mg of KSM-66 root extract twice daily for eight weeks raised testosterone by about 96 ng/dL, compared with 18 ng/dL on placebo. The ashwagandha group also gained more bench-press strength. The extract’s supplier provided the product, and the trial was small.

Overweight men aged 40 to 70 (2019)

In a crossover trial of 57 men (43 completed), an extract providing 21 mg of withanolides a day raised salivary testosterone about 15% more than placebo after eight weeks, and DHEA-S about 18% more. But fatigue, vigor and sexual well-being didn’t improve more than with placebo. Salivary testosterone is also less reliable than a blood test.

Men with low sexual desire (2022)

A trial of 50 men with low sexual desire used 300 mg of root extract twice daily for eight weeks. Testosterone rose about 66 ng/dL more than with placebo, and sexual function scores improved. Some authors disclosed financial ties related to the study.

Infertile men (2009 to 2013)

Older studies in men with infertility, including one using 5 g of root powder daily for three months, reported higher testosterone along with better sperm counts and motility. Some lacked a proper placebo group, so they carry less weight.

How might ashwagandha raise testosterone?

The leading theory is stress. Ashwagandha has lowered cortisol in several trials, and chronically high cortisol can suppress the hormonal signals that tell the testes to make testosterone. Better sleep, which some trials also reported, may help indirectly. Neither mechanism is proven to be the main driver, and the effect may be largest in men who are stressed or sleeping poorly.

How much ashwagandha for testosterone?

There’s no established dose. The positive trials mostly used 600 mg a day of a standardized root extract (often 300 mg twice daily) for at least eight weeks. Some used much larger amounts of plain root powder.

Many testosterone-booster blends contain less. Testosil, for example, lists 300 mg of KSM-66 per serving, half the strongest trial dose. When comparing products, check the extract name, the milligrams and whether the label lists withanolide content. Our TestoPrime vs Testosil comparison shows how much ashwagandha dosing can vary between similar products, and the full Testosil review breaks down that label.

How long does it take?

Every trial measured results at eight weeks or later, so don’t judge ashwagandha after a week or two. If nothing has changed after two to three months, it probably isn’t going to do much for you.

Side effects and who should avoid it

Most men tolerate ashwagandha well in the short term. Reported side effects include stomach upset, loose stools and drowsiness. More serious concerns:

• Liver injury. The NIH LiverTox database lists ashwagandha as a probable cause of rare liver injury, usually appearing two to 12 weeks after starting. Stop and see a doctor if you develop yellow skin or eyes, dark urine or itching.
• Thyroid. It may raise thyroid hormone levels. Take extra care with thyroid disease or thyroid medication.
• Autoimmune conditions and prostate cancer. It may stimulate the immune system and has hormonal effects, so get medical advice first.
• Interactions. Sedatives, alcohol, immunosuppressants, and diabetes or blood pressure drugs.
• Long-term use. Most trials lasted three months or less, so long-term safety isn’t well studied.

Ashwagandha vs other testosterone boosters

Among herbs, ashwagandha and fenugreek have the most consistent human data; tribulus has largely failed to raise testosterone in trials. Tongkat ali has a supportive meta-analysis but quality concerns. See Tongkat Ali vs Ashwagandha for a head-to-head look, and our testosterone support hub for full product comparisons.

If you have symptoms of low testosterone, start with a morning blood test. Supplements can’t fix a medical cause such as a pituitary problem, and some symptoms overlap with thyroid disease, depression or sleep apnea.

Does ashwagandha increase testosterone?

Small trials show modest increases, about 15% over placebo after eight weeks, mainly in young men who were training or men with infertility or low libido. Evidence in men with diagnosed low testosterone is lacking.

How much ashwagandha should I take to boost testosterone?

Most positive trials used 600 mg a day of a standardized root extract, often split into two 300 mg doses, for at least eight weeks. There’s no officially established dose.

How long does it take for ashwagandha to increase testosterone?

Studies measured changes at eight weeks or longer. Expect to wait about two months before judging any effect.

Can ashwagandha lower testosterone?

Clinical trials in men haven’t shown a drop in testosterone with ashwagandha. Its main known risks are rare liver injury and effects on thyroid hormones.