Ashwagandha Side Effects: Who Should Avoid It and Liver Risks

Is Ashwagandha Safe? Side Effects and Who Should Avoid It

Ashwagandha may be safe when taken short term for up to three months, but the lack of long-term research leaves its extended safety unknown. According to the ODS, ashwagandha appears well tolerated in clinical trials lasting up to about three months. Most reported adverse events are mild. Stomach upset, loose stools, nausea, and drowsiness occur most frequently. The NCCIH notes that diarrhea and vomiting also occur in some people.

Certain groups face higher risks and should avoid ashwagandha completely:

• Pregnant and breastfeeding individuals: The NCCIH advises people to avoid ashwagandha during pregnancy and while breastfeeding. The ODS fact sheet notes that some experts advise against use during pregnancy because of reports that it could cause miscarriage. The American Herbal Pharmacopoeia states that there is no evidence the root causes miscarriage, so health authorities treat pregnancy use as a caution rather than a proven harm.
• People with thyroid disorders: Ashwagandha can raise thyroid hormone levels. The NCCIH does not recommend the supplement for individuals with thyroid conditions. Review your status with a thyroid panel and read our overview of ashwagandha and thyroid function.
• People with autoimmune conditions: The NCCIH does not recommend ashwagandha for people with autoimmune diseases.
• People with prostate cancer: Because ashwagandha may raise testosterone levels, people with hormone-sensitive prostate cancer should avoid it.
• People scheduled for surgery: The NCCIH advises stopping ashwagandha before upcoming surgical procedures.

Ashwagandha and Liver Injury

Liver injury linked to ashwagandha is rare, but documented cases show that it can cause serious complications. The NCCIH reports that a number of cases link liver injury to ashwagandha supplements. The ODS describes five cases in adults aged 21 to 62 years who took 450 to 1,350 mg of ashwagandha daily for one week to four months. Symptoms included jaundice, itching, nausea, lethargy, and abdominal discomfort. All five patients improved after stopping the supplement. Not every product's contents were independently verified.

A 2020 study by Björnsson and colleagues evaluated five patients across Iceland and the United States Drug-Induced Liver Injury Network (DILIN). Jaundice appeared 2 to 12 weeks after starting ashwagandha. None of the patients developed liver failure. Liver tests normalized within one to five months in four of the patients.

A 2023 study by Philips and colleagues in India evaluated eight patients with liver injury from single-ingredient ashwagandha products. Five of those eight individuals had underlying chronic liver disease. Three of those patients developed acute-on-chronic liver failure and died. Chemical testing of the supplements found no contamination. This indicates that people with existing liver disease face the highest risk of severe injury. If you experience yellowing skin or eyes, itching, nausea, lethargy, or abdominal discomfort, stop taking ashwagandha immediately and obtain a liver function test.

Prescription Drug Interactions

Ashwagandha is listed as a potential interaction with six major classes of prescription medications. Both NCCIH and ODS list them. The six categories include:

• Sedatives: Drowsiness is a common side effect of ashwagandha, and sedatives are listed as a possible interaction.
• Anticonvulsants: Medications prescribed for seizure control are listed as a possible interaction.
• Thyroid hormone medications: Because ashwagandha can raise thyroid hormone levels, taking it alongside levothyroxine or other thyroid drugs may alter circulating hormone concentrations.
• Diabetes medications: Medicines prescribed to control blood sugar are listed as potential interacting agents.
• Blood pressure medications: Antihypertensive drugs are listed by federal agencies as an interacting drug class.
• Immunosuppressants: Medications prescribed to dampen immune responses are listed as an interaction concern.

Do not alter prescription medications on your own. Always consult your prescribing doctor before adding any herbal extract to your routine.

Why Some Countries Restrict Ashwagandha

Regulatory agencies in Europe have restricted or warned against ashwagandha due to unresolved safety questions regarding hormones and pregnancy. Denmark banned ashwagandha supplements in 2023. This regulatory decision followed a 2020 Danish risk assessment cited by the ODS that raised possible effects on pregnancy and on thyroid and sex hormones. According to reporting by the McGill Office for Science and Society, Danish authorities stated that current data made it impossible to establish a safe dose.

In 2024, according to the ODS fact sheet, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) issued an advisory. The agency recommended against ashwagandha consumption for specific groups, including pregnant women, breastfeeding women, and individuals with endocrine disorders.

In the United States, dietary supplements operate under different rules. As the NCCIH explains in its guidance on using dietary supplements wisely, supplements are not approved by the Food and Drug Administration (FDA) before they are sold. Manufacturers bear the legal responsibility for ensuring product safety and accurate labeling.

What Ashwagandha Does in Clinical Trials

Clinical trials evaluate ashwagandha primarily for stress, sleep, and serum cortisol, but study sizes remain relatively small. The ODS reviewed a 2021 analysis of seven trials evaluating stress and anxiety across 491 adults over 6 to 8 weeks. Trial doses ranged from 240 to 1,250 mg daily. Benefits appeared greater in trials using 500 to 600 mg per day. The NCCIH notes that while some preparations may help with insomnia and stress, evidence for anxiety remains unclear.

A 2021 sleep meta-analysis covering five studies and 372 adults examined root extracts at 250 to 600 mg daily. In a 2012 trial by Chandrasekhar and colleagues, 64 stressed adults took 300 mg of root extract twice daily for 60 days. Serum cortisol fell 27.9% in the extract group compared to a 7.9% drop in the placebo group. Side effects were mild and occurred at similar rates between both groups. Trials by Salve in 2019 using 250 to 600 mg daily and Lopresti in 2019 using 240 mg daily also observed lower cortisol compared to placebo. To learn how lifestyle strategies compare, see our guide to lower cortisol and our review of high cortisol symptoms.

Some people explore ashwagandha for weight loss, but research shows only modest, stress-related changes. In an eight-week trial by Choudhary and colleagues, 52 adults under chronic stress received 300 mg twice daily. Body weight dropped 2.32 kg (3.03%) in the ashwagandha group compared to 1.13 kg (1.46%) on placebo. Serum cortisol dropped 22.2%, and food craving scores improved. This reflects a small, stress-related outcome from a single short study. In a 12-week study of 120 overweight adults cited by the ODS, a proprietary extract failed to reduce perceived stress, though participants reported lower fatigue.

How to Approach Ashwagandha More Safely

Anyone choosing to trial ashwagandha should keep use within the three-month window evaluated in clinical studies. Long-term safety data does not exist. Setting a clear end date reduces unknown exposure risks. The 2021 stress review covered 240 to 1,250 mg a day and saw greater benefit at 500 to 600 mg, so no trial supports taking higher doses. In the liver injury cases described by the ODS, patients took 450 to 1,350 mg daily.

Choose products that have undergone third-party testing, as explained in our guide to third-party lab tested supplements. Always inform your doctor about any supplement you plan to start. If symptoms such as jaundice, unexplained itching, lethargy, or abdominal discomfort occur, stop taking the extract immediately and contact your doctor.

Alternatives If Ashwagandha Is Ruled Out

Finding practical ashwagandha alternatives depends on your primary symptom. Three compounds offer human trial data: rhodiola, magnesium, and L-theanine. Each compound addresses a different reason ashwagandha was ruled out.

Rhodiola targets fatigue and low energy from ongoing stress. Across 19 human trials, daily doses ranged from 120 to 1,000 mg. A 2021 review reported greater stress relief at 500 to 600 mg daily.

In a 2009 trial, Olsson and colleagues gave 576 mg daily to adults with stress-related fatigue. A 2012 trial by Edwards and colleagues tested 200 mg twice daily for fatigue and sleep. Our ashwagandha versus rhodiola comparison covers safety details for this herb.

Magnesium supports sleep quality and helps lower evening cortisol levels. In an eight-week trial, Abbasi and colleagues gave 500 mg daily of elemental magnesium to 46 older adults with primary insomnia. Serum cortisol dropped compared to placebo.

The National Institutes of Health (NIH) Office of Dietary Supplements sets the Recommended Dietary Allowance (RDA) for adult men at 400 to 420 mg daily. For adult women, the RDA is 310 to 320 mg daily. Supplemental magnesium has a Tolerable Upper Intake Level (UL) of 350 mg daily for adults.

The 500 mg trial dose exceeds this supplemental UL. That figure represents research data rather than a routine home target. High supplemental doses often cause loose stools.

Our ashwagandha versus magnesium guide compares how both options affect evening rest. Readers exploring nighttime cortisol can also review our guide on cortisol and sleep.

L-theanine is an amino acid in green tea that promotes calm without causing drowsiness. In a 2024 trial by Lim and colleagues, 18 female college archers received 200 mg daily for four weeks. Both cognitive anxiety and salivary cortisol measured lower than placebo shortly before competition (p < .05).

A safety trial tested 400 mg daily of the AlphaWave ingredient across 30 adults for 28 days. Researchers reported no clinically relevant changes in vital signs or blood chemistry. Only two mild adverse events occurred: dry mouth and a metallic taste.

No official RDA or UL exists for L-theanine. Unlike ashwagandha, no comparable case-report literature exists for L-theanine at studied doses. It provides a daytime calming option without sedation.

Match your choice to the reason you ruled ashwagandha out. Choose rhodiola for stress-related fatigue, or magnesium for insomnia and night waking. If you ruled out ashwagandha over thyroid or liver warnings, no comparable case-report literature exists for L-theanine at studied doses.

None of these alternatives are completely risk-free. Ashwagandha remains unsuitable for pregnant individuals, people with autoimmune conditions, thyroid disorders, or liver disease. Future clinical research may clarify these safety risks as larger trials publish.