Ashwagandha, also called Withania somnifera, contains bioactive compounds known as withanolides. Researchers often measure cortisol because this hormone participates in the body’s stress response. That biological response is not the same as improved mood, less anxiety, better sleep, or better daily functioning.

A 2025 meta-analysis combined randomized trials involving 488 participants. Ashwagandha lowered cortisol by an average of 1.16 micrograms per deciliter, but it did not meaningfully improve perceived-stress scores. The studies varied moderately, and their overall risk of bias was generally moderate. A

A registered 84-day trial enrolled 90 adults with non-chronic mild-to-moderate stress. Compared with placebo, 125 milligrams of the branded Zenroot formulation improved perceived-stress, anxiety, and sleep-quality scores at several time points. It did not lower serum cortisol or salivary alpha-amylase. All participants completed the study, and investigators reported no product-related adverse events.

A registered 30-day trial in 60 healthy college students tested 700 milligrams per day of a full-spectrum root extract. Its primary combined analysis found no meaningful group-by-time difference for sleep and stress. An adjusted follow-up analysis favored ashwagandha for final sleep

In a six-week placebo-controlled trial, 150 healthy adults with prominent non-restorative sleep symptoms received 120 milligrams of a standardized extract or placebo. Among the 144 people who completed the study, self-reported sleep quality improved by 72 percent with the extract and 29 percent with placebo. Researchers also used a movement sensor to assess sleep onset, sleep efficiency, total sleep time, and nighttime waking, but the available report does not establish improvement in each measure. It therefore does not support a firm conclusion that ashwagandha helps people fall asleep faster.

The National Center for Complementary and Integrative Health concludes that some preparations may help insomnia and stress, while anxiety evidence remains unclear. One 12-week trial found better anxiety-related scores among 66 people with schizophrenia who received 1,000 milligrams of standardized extract

Short-term use is better studied than long-term use. NCCIH reports that ashwagandha can cause drowsiness, stomach upset, diarrhea, and vomiting. Rare cases have linked supplements containing it to liver injury. Trials that found few adverse events were too small and brief to rule out rare harms, and cortisol studies have not adequately examined long-term adrenal effects.

NCCIH advises avoiding ashwagandha during pregnancy and breastfeeding and does not recommend it before surgery or for people with autoimmune or thyroid disorders. Potential interactions include medicines for diabetes or high blood pressure, sedatives, anti-seizure drugs, immunosuppressants, and thyroid hormone. Dietary

Ashwagandha, also called Withania somnifera, contains bioactive compounds known as withanolides. Researchers often measure cortisol because this hormone participates in the body’s stress response. That biological response is not the same as improved mood, less anxiety, better sleep, or better daily functioning.

A 2025 meta-analysis combined randomized trials involving 488 participants. Ashwagandha lowered cortisol by an average of 1.16 micrograms per deciliter, but it did not meaningfully improve perceived-stress scores. The studies varied moderately, and their overall risk of bias was generally moderate. A

A registered 84-day trial enrolled 90 adults with non-chronic mild-to-moderate stress. Compared with placebo, 125 milligrams of the branded Zenroot formulation improved perceived-stress, anxiety, and sleep-quality scores at several time points. It did not lower serum cortisol or salivary alpha-amylase. All participants completed the study, and investigators reported no product-related adverse events.

A registered 30-day trial in 60 healthy college students tested 700 milligrams per day of a full-spectrum root extract. Its primary combined analysis found no meaningful group-by-time difference for sleep and stress. An adjusted follow-up analysis favored ashwagandha for final sleep

In a six-week placebo-controlled trial, 150 healthy adults with prominent non-restorative sleep symptoms received 120 milligrams of a standardized extract or placebo. Among the 144 people who completed the study, self-reported sleep quality improved by 72 percent with the extract and 29 percent with placebo. Researchers also used a movement sensor to assess sleep onset, sleep efficiency, total sleep time, and nighttime waking, but the available report does not establish improvement in each measure. It therefore does not support a firm conclusion that ashwagandha helps people fall asleep faster.

The National Center for Complementary and Integrative Health concludes that some preparations may help insomnia and stress, while anxiety evidence remains unclear. One 12-week trial found better anxiety-related scores among 66 people with schizophrenia who received 1,000 milligrams of standardized extract

Short-term use is better studied than long-term use. NCCIH reports that ashwagandha can cause drowsiness, stomach upset, diarrhea, and vomiting. Rare cases have linked supplements containing it to liver injury. Trials that found few adverse events were too small and brief to rule out rare harms, and cortisol studies have not adequately examined long-term adrenal effects.

NCCIH advises avoiding ashwagandha during pregnancy and breastfeeding and does not recommend it before surgery or for people with autoimmune or thyroid disorders. Potential interactions include medicines for diabetes or high blood pressure, sedatives, anti-seizure drugs, immunosuppressants, and thyroid hormone. Dietary