How does ashwagandha help with weight loss?

Ashwagandha is an herb with a rich history in India's Ayurvedic medicine practices that is used today largely to help manage stress. Emerging research suggests ashwagandha may also support weight loss by helping to lower levels of the stress hormone cortisol. It may also offer other potential health benefits, such as improving sleep quality.

Ashwagandha does not directly burn fat or boost metabolism, but it may help with modest weight loss by reducing stress and lowering cortisol levels.

One study investigated the impact of ashwagandha supplementation for eight weeks in stressed people with overweight or obesity who had body mass indexes (BMI) of 25–39.9 kg/m². Participants were placed in either the ashwagandha group, which took two 300 mg doses of ashwagandha daily, or the control group, which took two placebo pills a day.

At the end of the study, the ashwagandha group experienced:

• 32.7% reduction in perceived stress

• 22.2% reduction in blood cortisol levels

• Less uncontrolled and emotional eating

While there was a weight reduction of around 3% during the eight weeks for the ashwagandha group, the control group also experienced an average weight reduction of about 1.5% — a modest difference. 

Although supplementation did not result in big changes in body weight over the eight-week period, participants did manage to lose some weight in a short period of time without any other dietary changes.

Newer research also supports ashwagandha for stress reduction and weight loss. In a 2025 study, participants took ashwagandha for 24 weeks and experienced reduced stress levels, fewer food cravings, and decreased body weight.

More studies are needed to better understand this connection. It remains unclear whether ashwagandha works better for preventing stress-related weight gain or for actively promoting weight loss. Ashwagandha for weight loss specifically would likely have the most impact when paired with a calorie-deficit diet.

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To understand how ashwagandha may help with weight loss, it helps to first understand what ashwagandha is and how it may affect the stress hormone cortisol.

Ashwagandha, scientifically known as Withania somnifera, is an adaptogen for stress and is one of the most studied adaptogens. Adaptogens are herbs that help improve the body's ability to adapt to and cope with stress. One way to measure the body's stress level is through the hormone cortisol.

Cortisol is a stress hormone that supports the body’s "fight or flight" response. It runs high in times of emotional and physical stress — like during a breakup or when someone is being chased. When cortisol increases in those short-term, infrequent scenarios, it is beneficial, keeping a person alert and raising glucose, or blood sugar, levels to provide a needed energy boost.

But when cortisol is elevated all of the time, it can:

• Shift the body’s metabolism to store more fat

• Decrease energy levels

• Interfere with sleep

• Weaken the immune system

• Increase risk for heart disease, high blood pressure, and type 2 diabetes 

Research suggests that ashwagandha supplements may help lower cortisol levels and reduce levels of perceived stress. In a study of 64 adults, researchers found that the group who received 300 mg of ashwagandha supplements twice daily experienced, on average, a 44% reduction in perceived stress scores after two and a half months. 

Ashwagandha supplementation also reduced blood cortisol levels by around 27%, compared with an 8% reduction in the placebo group.

So, ashwagandha seems to improve stress levels in some people, but does that translate to helping with weight loss? 

Ashwagandha is considered to be generally safe. It can be found as capsules, powdered supplements, or tea. 

It has been studied in doses ranging from 250 mg to 600 mg a day to combat stress, anxiety, and to promote sleep and weight loss. These doses are typically split and consumed at different times — with one dose after a morning meal and one in the afternoon or evening.

Ashwagandha may promote weight loss or weight maintenance in people who are chronically stressed. If you are not chronically stressed, this supplement may not address your needs. Talk to a healthcare provider if you feel like you are experiencing stress-related weight gain or loss.

Ashwagandha is generally well tolerated for short-term use, but it can cause mild side effects. Long-term safety is unknown, and it may trigger rare but serious liver issues or interact with certain medications.

Possible side effects include:

• Upset stomach

• Diarrhea

• Nausea

• Vomiting

• Drowsiness

There are some case reports of people experiencing liver injury after taking ashwagandha supplements. However, since supplements are not regulated by the US Food and Drug Administration (FDA), we cannot be sure exactly what was in those supplements. 

Sometimes supplements can contain hidden, dangerous ingredients, so it is possible the liver injury was due to a contaminant rather than the ashwagandha itself.

Additionally, ashwagandha supplements may interact with certain medications, including:

• Antidiabetes medications

• Antihypertensives

• Immunosuppressants

• Sedatives 

As always, talk with a healthcare provider before adding a new supplement to your routine, especially to check for potential interactions with prescription medications. This can help reduce your risk of side effects or safety issues.

Who should avoid ashwagandha?

Some groups of people who should not take ashwagandha include:

• Pregnant or breastfeeding people

• People with hormone-sensitive conditions (such as prostate cancer, breast cancer, or thyroid disorders)

• People with autoimmune conditions (such as lupus, rheumatoid arthritis, or Hashimoto’s thyroiditis)

If you are unsure whether this supplement is safe for you, consult a healthcare provider.

Much more research is needed before ashwagandha can be considered a mainstream remedy, but there is some research suggesting that ashwagandha's health benefits may extend beyond stress and weight loss:

• Testosterone levels: Research in men suggests that supplementing with ashwagandha may increase testosterone levels, but oftentimes, researchers do not know if increases in testosterone levels happen because of the supplement or by chance.

• Muscle strength: Ashwagandha supplementation along with resistance training may help muscle mass, growth, and strength, and may help prevent muscle breakdown from high cortisol levels.

• Enhance sleep: Ashwagandha supplementation may improve measures of sleep, either by directly affecting sleep or by reducing the stress that can interfere with it.

• Reduce inflammation: Ashwagandha is rich in antioxidants, which may help combat oxidative stress that leads to inflammation.

Ashwagandha supplements may be part of a weight maintenance or weight loss plan for people experiencing chronic stress. This Ayurvedic herb's most notable and well-studied benefit is reducing stress by lowering cortisol levels and feelings of perceived stress. It may also help regulate emotional eating patterns. But to more directly target weight loss, ashwagandha should be paired with proven strategies, such as a healthy eating plan and exercise.

If you have any questions about how a supplement may affect your body, it is wise to speak with a healthcare provider.

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If you are experiencing chronic stress and trying to lose weight, you may be considering ashwagandha supplements.

• Ashwagandha may indirectly help with modest weight loss by reducing stress and lowering cortisol levels. It does not directly target fat. 

• Ultimately, more research is needed to determine its effectiveness. It is also unclear whether ashwagandha would still help with weight loss in people who are not chronically stressed.

• Ashwagandha may also provide other health benefits, such as improved sleep, reduced inflammation, increased muscle strength, and even potentially boosted testosterone levels. 

• Ashwagandha can cause side effects such as drowsiness and upset stomach. It is also not safe for everyone, so check with a healthcare provider before taking it.