Does Ashwagandha Cause Weight Gain? Separate Claims From Evidence

There is no good evidence that ashwagandha causes weight gain in adults. In the placebo-controlled trials we found that reported weight results, none showed a statistically significant weight gain with ashwagandha compared with placebo, and a 2026 systematic review and meta-analysis of randomized trials found no significant effect on body weight or body fat percentage. Zhu 2026, PubMed.

One caution keeps that answer honest. A 2020 review of human studies listed weight gain among less common reported side effects, alongside decreased appetite, without saying how often it happened or showing that ashwagandha caused it. Tandon 2020, PubMed. So if your weight changes after you start a product, look at the exact label, the timing, your symptoms, and everything else that changed before you blame or clear the supplement.

The opposite claim also goes too far. Some trials reported more weight loss with an ashwagandha extract than with placebo, a 2025 pilot trial found no significant change, and the pooled analysis found no significant effect on body weight. That is not evidence of a weight-loss treatment. The federal National Center for Complementary and Integrative Health (NCCIH) does not list weight change among the effects described on its ashwagandha page. NCCIH: ashwagandha.

What official sources say, and what they leave out

Ashwagandha (Withania somnifera) is an evergreen shrub that has been used for thousands of years in traditional Ayurvedic medicine. NCCIH says supplements are often promoted for stress and anxiety, sleep, male infertility, and athletic performance, and they typically contain root, leaf, or root and leaf extracts. NCCIH: ashwagandha.

NCCIH reports that some ashwagandha preparations may be effective for insomnia and stress, while the evidence on anxiety is unclear. It says there is not enough evidence to determine whether ashwagandha helps other conditions, including athletic performance and diabetes. It also notes that many studies have had small sample sizes and used a variety of preparations. NCCIH: ashwagandha.

Body weight is not part of that summary. So a product page that turns “may help stress” into “helps you lose weight” or “won't affect your weight” is adding a claim the federal overview does not make.

What the trials that measured weight actually found

These four placebo-controlled trials show the range of results behind weight claims. Each tested one ashwagandha preparation in one group of people.

Sources for the table: Choudhary 2017, Pakhale 2025, Ballesteros-Torres 2025, Wankhede 2015, all on PubMed. We describe what the published reports state, mostly from their abstracts, and add no results they do not report.

Put together, the four trials point in different directions, and none shows weight gain. The 2015 and 2017 trials share authors, so they are not fully independent of each other. The 2026 meta-analysis of randomized trials found no significant effects on body weight or body fat percentage. Zhu 2026, PubMed. Each trial also tested one preparation in one group for a limited time, and NCCIH still describes the evidence for athletic performance as insufficient. NCCIH: ashwagandha.

Why “it lowers stress, so it changes weight” is not proof

Stress and sleep do matter for weight. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) lists long-term stress among health problems that may lead to weight gain and says not getting enough sleep is linked to weight gain. NIDDK: factors affecting weight and health.

That does not make a stress supplement a weight treatment. A study can report a better stress score without showing any clinically useful change in weight. Stress results also vary by product and group: in a 12-week trial in overweight or mildly obese adults aged 40 to 75 with high stress and fatigue, perceived stress fell with ashwagandha but not significantly more than with placebo. Smith 2023, PubMed.

To support a weight claim, look for a study that measured weight or body composition, compared the product with a placebo, described who took part, and tested the same preparation and amount you are considering.

“Cortisol support,” “adaptogen,” and “hormone balance” are not defined medical results. A body-shape photo cannot diagnose a cortisol problem. NIDDK lists conditions such as Cushing's syndrome and hypothyroidism among health problems that may lead to weight gain, and those need a clinician's evaluation, not a supplement guess. NIDDK: factors affecting weight and health.

Does ashwagandha increase belly fat or make weight loss harder?

We did not find a human study showing that ashwagandha increases belly fat or blocks weight loss. In the 2025 pilot trial, the abstract reported no statistically significant change in waist circumference. Ballesteros-Torres 2025, PubMed. A 2026 meta-analysis of resistance-training trials found no dependable effect on body fat. Lee 2026, PubMed.

If your waist or weight changes while you take it, treat that as a change to review, not as a verdict on the supplement in either direction. For belly-fat concerns tied to polycystic ovary syndrome, see our guide to PCOS belly.

How to review a weight change while taking it

Weight is affected by many factors. NIDDK names lifestyle habits, your surroundings, how much sleep you get, medicines, health problems, and family history and genes. A supplement start date is a useful clue, but timing alone does not prove the cause. NIDDK: factors affecting weight and health.

Write down when you started the product, how much you take, any change in amount, and when the weight change began. Add anything else that changed around the same time: a new prescription, a different sleep schedule, less activity, more snacking, or another supplement. Note symptoms, not just numbers, such as swelling, stomach problems, unusual tiredness, or changes in appetite and sleep.

Some medicines can contribute to weight gain, including corticosteroids, some diabetes medicines, and some medicines for depression, epilepsy, psychotic disorders, high blood pressure, and allergies. If you started or changed one of these, mention it at the same review. Our guides to Cymbalta and weight gain and buspirone and weight changes show how a medicine's label reports weight changes. NIDDK: factors affecting weight and health.

Rapid gain can also be fluid. MedlinePlus explains that swelling is caused by fluid building up in the tissues and that this extra fluid can lead to a rapid increase in weight over days to weeks. Causes it lists include heart failure, kidney disease, liver disease, thyroid disease, and some medicines. If you notice unexplained swelling, contact your health care provider. Swelling with shortness of breath can signal an emergency such as pulmonary edema, for which MedlinePlus says rapid diagnosis and treatment is important, so get medical care right away. MedlinePlus: swelling.

If you have side effects, stop taking the supplement and contact your health care provider, as NCCIH advises. Do not restart it or add other products to “test” the effect, and do not stop or change a prescription medicine without talking with your clinician or pharmacist. Bring the bottle or a clear photo of the label, but know that a label may not list everything: NCCIH warns that some products promoted mainly for weight loss, sexual enhancement, or bodybuilding may contain prescription drugs or other ingredients not listed on the label. NCCIH: using dietary supplements wisely.

A claim-checking table for labels and ads

Source for the last row: NCCIH: using dietary supplements wisely. This table does not certify or recommend any product. It separates an evidence question from a marketing phrase.

Safety: who should avoid ashwagandha

NCCIH says ashwagandha may be safe in the short term, up to 3 months, and that there is not enough information to reach conclusions about long-term safety. In some people, preparations may cause drowsiness, stomach upset, diarrhea, and vomiting. Although rare, a number of cases have linked liver injury to ashwagandha supplements. NCCIH: ashwagandha.

Know the signs MedlinePlus lists for liver disease: swelling of the abdomen and legs, bruising easily, changes in the color of your stool and urine, and jaundice, or yellowing of the skin and eyes. If you notice any of these while taking ashwagandha, stop taking it and contact your health care provider promptly. MedlinePlus: liver diseases, NCCIH: using dietary supplements wisely.

According to NCCIH:

• Avoid ashwagandha during pregnancy, and do not use it while breastfeeding.
• It is not recommended for people about to have surgery or for people with autoimmune or thyroid disorders.
• It might interact with some medicines, including those for diabetes and high blood pressure, immunosuppressants, sedatives, anti-seizure medicines (anticonvulsants), and thyroid hormone medicines.
• Because it may increase testosterone levels, people with hormone-sensitive prostate cancer should avoid it.

NCCIH: ashwagandha.

Tell every clinician and pharmacist about all the supplements you use, even when the store calls them a food, a wellness gummy, or a natural remedy. A product sold without a prescription can still matter for prescription safety. If you develop persistent vomiting or another significant new symptom, stop taking it, seek medical advice, and mention the supplement. You can report a safety concern about a dietary supplement through the U.S. Health and Human Services Safety Reporting Portal. NCCIH: using dietary supplements wisely.

Does “natural” or a quality claim settle the question?

No. NCCIH notes that “natural” does not always mean safe, and that a manufacturer's use of terms such as “standardized,” “verified,” or “certified” does not necessarily guarantee product quality or consistency. Unlike drugs, dietary supplements are not approved by the U.S. Food and Drug Administration before they are sold; manufacturers are responsible for evaluating the safety and labeling of their products. NCCIH: using dietary supplements wisely, NCCIH: ashwagandha.

For a different supplement format, our guide to weight-loss patches explains why a delivery format and an advertising claim do not establish a treatment benefit.

If weight management is your goal

You do not need to settle the supplement question before asking for a broader review. Ask what is contributing to your weight pattern, whether treatment is appropriate, and which options have evidence for your health situation. A clinician can separate a weight-management goal from a possible medicine, supplement, or medical issue.

If a scale change might be fluid or bloating rather than fat, our guide to bloating versus fat explains the difference. If constant thoughts about eating are part of the picture, our explanation of what “food noise” means covers that everyday concern without treating the phrase as a diagnosis.

Majesta Health is the publisher of this educational resource. This article does not recommend ashwagandha or establish eligibility for a prescription.

Educational information for adults, not an individual treatment plan. Sources retrieved and checked October 28, 2026, including a PubMed search that day. NCCIH's ashwagandha page was last updated March 2023. The trials described are small or short and specific to the preparations and people studied, and their descriptions here come from the published reports.

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