Ashwagandha

What is ashwagandha?

Ashwagandha (Withania somnifera) is an evergreen shrub from India, Africa and the Middle East whose root has been used in Ayurvedic medicine for thousands of years. It contains withanolides, compounds associated with anti-inflammatory and antioxidant effects. Today it is marketed mainly for stress, sleep, male fertility and athletic performance (NCCIH).

What the research says

Ashwagandha is one of the better studied adaptogens. NCCIH states that some preparations may be effective for insomnia and stress, while evidence on anxiety is less clear (NCCIH). A 2022 meta-analysis of 12 randomized trials with about 1,000 participants found reductions in stress and anxiety scores compared with placebo, with stress benefits seen at 300 to 600 mg per day, although the certainty of the evidence was rated low because studies varied a lot (Akhgarjand et al., 2022).

On male hormones, NCCIH notes limited evidence that taking ashwagandha for two to four months may increase testosterone levels and sperm quality (NCCIH). In a crossover trial of overweight men aged 40 to 70, a standardized extract raised salivary testosterone by about 15% and DHEA-S by 18% more than placebo, but did not improve fatigue, vigor or sexual well-being compared with placebo (Lopresti et al., 2019).

We found no clinical trials testing ashwagandha for prostate size or urinary symptoms. Claims that it “optimizes the detoxification of toxins which may build up in the prostate” are not based on human research.

How it’s used in supplements

Ashwagandha is sold as root powder or standardized extracts (for example, extracts standardized to a percentage of withanolides), commonly at 250 to 600 mg per day. It appears in stress, sleep and men’s vitality products.

Safety matters here. NCCIH says ashwagandha may be safe for up to three months, but long-term safety is unknown; it can cause drowsiness and stomach upset, and rare cases of liver injury have been reported. It should be avoided in pregnancy and breastfeeding and by people with autoimmune or thyroid disorders, and it may interact with medicines for diabetes, blood pressure, seizures, thyroid disease, sedatives and immunosuppressants. Because ashwagandha may raise testosterone, NCCIH advises that people with hormone-sensitive prostate cancer avoid it (NCCIH).

The bottom line: ashwagandha is one of the better supported herbs for stress and sleep, and it may modestly raise testosterone in some men. That last point is a reason for caution, not enthusiasm, in a prostate product, because testosterone-raising supplements may not be appropriate for men with prostate cancer or those being monitored for it. If you choose to use ashwagandha, look for a standardized root extract at studied doses, limit use to a few months at a time, and stop and see a doctor if you notice signs of liver problems such as dark urine, yellowing of the skin or eyes, or unusual fatigue.