Withania somnifera

Some extracts may reduce subjective stress and anxiety.

For stress, consider the results for the specific extract; studies obtained different results.

Study result. In Arumugam 2024, the difference on the Perceived Stress Scale (PSS) was −4.72 points (95% CI −8.45 to −0.99). A later review found no convincing overall PSS difference.

Some extracts may reduce subjective stress and anxiety.

For anxiety, refer to the results of specific trials.

Study result. In the review, the difference on the HAM-A scale was −2.19 points (95% CI −3.83 to −0.55).

May improve sleep quality.

KSM-66 root extract has been studied for sleep.

Study result. In one study, the Pittsburgh Sleep Quality Index (PSQI) changed by −2.9 versus −1.4 points.

A specific root extract may reduce subjective fatigue in adults with existing complaints.

Witholytin extract was studied in people with baseline fatigue.

Study result. The final fatigue scores were 9.11 versus 11.55; these are group scores, not an individual prediction.

May improve some mood measures.

For mood, studies have examined individual scales in people with stress.

Study result. In one trial, the change in the DASS depression subscale was −13.5 versus −1.0 points.

Improvements in individual cognitive tests are possible. A noticeable improvement in everyday memory and attention has not been established.

For memory and attention, look at specific tests rather than generalizing the result to all cognitive functions.

Study result. In the review, the difference for memory tests was SMD 0.52 (95% CI 0.27–0.78), and for attention and speed 0.29 (0.07–0.51). These are standardized estimates across different tests, not percentages.

May improve some measures of strength and aerobic performance.

KSM-66 was studied alongside strength training in men starting training.

Study result. In the RCT, the machine bench press strength measure increased by 46.0 versus 26.4 kg.

May improve some measures of strength and aerobic performance.

KSM-66 was studied for aerobic performance in physically active adults.

Study result. Estimated VO₂max from a shuttle test increased by 5.67 versus 1.86 mL/kg/min.

Consistently faster recovery and reduced post-exercise muscle soreness have not been established.

For recovery, there is an individual result in professional female footballers.

Study result. In one RCT, subjective recovery ratings improved in professional female footballers. In other groups, recovery and soreness results were mixed.

One study of a specific extract reported weight loss in people with overweight.

KSM-66 was studied for body weight in adults with overweight.

Study result. In one RCT, body weight changed by −8.46 versus −2.41 kg. Both groups were instructed to maintain their usual diet and activity.

May improve sexual desire and some sperm measures in the studied groups. An increased likelihood of conception and live birth has not been established.

For sperm measures, consider the specific measure assessed.

Study result. The difference in change in total sperm count per ejaculate was +21.20 million (95% CI 6.09–36.30); there was no convincing difference in concentration or motility. Conception and live birth were not assessed.

Testosterone and sexual desire changed in individual studies. A predictable increase in testosterone in a healthy consumer has not been established.

Subjective sexual desire was studied in people with sexual complaints.

Study result. In one RCT, the authors reported improved subjective sexual desire; no convincing between-group increase in testosterone was shown.

Certain extracts may reduce subjective menopausal symptoms.

Root extracts were studied for symptoms of the menopausal transition.

Study result. In one RCT, the total MRS score changed from 31.37 to 18.53 versus 30.73 to 30.03. Some figures in the published tables are inconsistent.

May affect glucose under the studied conditions. Predictable improvement in HbA1c and prevention of diabetes have not been established.

For glucose measures, assess fasting glucose and HbA1c separately.

Study result. In the review, the mean difference in fasting glucose was −3.09 mg/dL; the HbA1c result was uncertain.

A predictable effect on blood pressure has not been established.

No separate reliable regimen for blood pressure was identified.

Study result. A predictable effect on blood pressure has not been shown.

Prevention of colds and infections has not been established.

For prevention of infections, refer to the specific study.

Study result. SARS-CoV-2 infection was recorded in 27 of 598 and 20 of 602; no convincing advantage was shown.

Stronger bones and fewer fractures have not been established.

For bone health, distinguish bone density from fracture risk.

Study result. In one RCT, the adjusted difference in lumbar T-score at 500 mg was 0.054 (95% CI 0.020–0.087); another study found no difference in density. Fractures were not assessed.

May improve some subjective measures of sexual function in women with complaints.

Root extract was studied in women with sexual function complaints.

Study result. The total Female Sexual Function Index (FSFI) score changed from 14.20 to 22.62 versus 14.17 to 19.25 with placebo.

There is a signal of improvement in some skin and hair measures with a specific extract. This does not establish treatment of hair loss.

The specific KSM-66 extract was studied for skin and hair.

Study result. Over 75 days in one RCT, the change in transepidermal water loss was −1.35 versus −0.39; some hair measures differed. Units for one hair growth measure in the article require clarification.