What is Ashwagandha?
Ashwagandha (Withania somnifera), also known as Indian ginseng or winter cherry, is an evergreen shrub native to India, the Middle East, and parts of Africa [1.7.1, 1.10.2]. For centuries, its root has been a cornerstone of traditional Ayurvedic medicine, where it's classified as an adaptogen—a substance believed to help the body manage stress [1.7.1]. Its use has surged globally for benefits related to stress, anxiety, sleep, and athletic performance [1.2.4]. However, despite its popularity, this herb is not universally safe and poses significant risks for certain individuals [1.5.3, 1.5.4]. Several countries, including Denmark, have even banned or restricted its sale due to safety concerns [1.3.2, 1.5.4].
Who Should Avoid Ashwagandha?
It is crucial to consult a healthcare provider before starting any new supplement, including ashwagandha. Specific populations should avoid it altogether due to potential health risks [1.5.5].
Pregnant and Breastfeeding Individuals
Ashwagandha is considered likely unsafe during pregnancy [1.3.4]. There is evidence suggesting it may cause uterine contractions and could potentially lead to miscarriage [1.5.5, 1.8.2, 1.8.4]. Due to a lack of sufficient safety information, its use is also not recommended while breastfeeding [1.3.4, 1.8.5].
People with Autoimmune Diseases
Ashwagandha may cause the immune system to become more active [1.6.3]. For individuals with autoimmune conditions—such as rheumatoid arthritis (RA), lupus (systemic lupus erythematosus, SLE), multiple sclerosis (MS), and Hashimoto's thyroiditis—this immune-stimulating effect can increase symptoms [1.3.3, 1.6.1]. Taking ashwagandha could counteract the effects of immunosuppressant medications prescribed for these conditions [1.4.4].
Individuals with Thyroid Disorders
Ashwagandha can increase thyroid hormone levels (T3 and T4) [1.7.1, 1.7.4]. While this may be beneficial for some individuals with an underactive thyroid (hypothyroidism), it can be dangerous for those with an overactive thyroid (hyperthyroidism) by potentially causing thyrotoxicosis—a condition of excessively high thyroid hormone levels [1.7.1, 1.7.3]. People taking thyroid hormone medications should use ashwagandha with caution or avoid it, as the combination could lead to hormone levels rising above the normal range [1.3.3, 1.3.4].
Those with Liver Problems
Though rare, there are multiple reports of ashwagandha causing liver injury, ranging from mild issues to severe liver failure requiring a transplant [1.3.4, 1.10.1, 1.10.2]. The National Institutes of Health's LiverTox database classifies ashwagandha as a likely cause of clinically apparent liver injury [1.10.1]. Individuals with pre-existing liver disease may be at a higher risk of severe outcomes, and some research suggests that fatalities have occurred in patients with underlying chronic liver disease who took the supplement [1.10.5].
People Scheduled for Surgery
Ashwagandha may slow down the central nervous system, producing a sedative effect [1.9.1, 1.9.5]. Healthcare providers worry that this could dangerously interact with anesthesia and other medications used during and after surgery [1.6.3]. It is recommended to stop taking ashwagandha at least two weeks before a scheduled surgical procedure to avoid these potential interactions [1.3.4, 1.9.1].
Individuals with Hormone-Sensitive Prostate Cancer
Some evidence suggests that ashwagandha can increase testosterone levels [1.3.2, 1.4.5]. Because of this, experts advise that it may not be safe for individuals with hormone-sensitive prostate cancer, as increased testosterone could interfere with treatment [1.3.2, 1.5.4].
Individuals Taking Certain Medications
Ashwagandha can interact with numerous prescription drugs. Combining it with other substances can enhance or weaken their effects, leading to negative health consequences [1.2.3].
| Medication Type | Potential Interaction with Ashwagandha |
|---|---|
| Sedatives (Benzodiazepines, Barbiturates, CNS Depressants) | Ashwagandha has sedative properties and can cause sleepiness and slowed breathing. Combining it with sedatives like Xanax (alprazolam), Klonopin (clonazepam), or Ambien (zolpidem) can cause excessive drowsiness and potentially breathing problems [1.4.1, 1.4.3, 1.4.4]. |
| Immunosuppressants | By stimulating the immune system, ashwagandha can decrease the effectiveness of medications designed to suppress the immune system, such as those used after organ transplants or for autoimmune conditions [1.4.4, 1.6.3]. |
| Thyroid Hormone Medication | Ashwagandha can increase the body's production of thyroid hormones. Taking it with thyroid medication (e.g., levothyroxine) may cause an excess of thyroid hormone in the body, amplifying effects and side effects [1.3.4, 1.7.2]. |
| Diabetes Medications (Antidiabetes drugs) | Ashwagandha might lower blood sugar levels. Taking it alongside diabetes medications like insulin or metformin could cause blood sugar to drop too low (hypoglycemia). Close monitoring is essential [1.3.4, 1.4.1]. |
| Blood Pressure Medications (Antihypertensive drugs) | Ashwagandha may lower blood pressure. Combining it with medications for hypertension could cause blood pressure to become too low (hypotension) [1.3.4, 1.4.1]. |
| Hepatotoxic Drugs (Medications that can harm the liver) | Taking ashwagandha with other medications that carry a risk of liver damage could increase the overall risk of liver injury [1.3.4, 1.4.1]. |
General Side Effects
Even for individuals who do not fall into the categories above, ashwagandha can cause side effects. The most common are digestive upset, including diarrhea, nausea, and vomiting, particularly in large doses [1.2.4, 1.5.4]. Drowsiness is also a frequently reported side effect [1.5.5]. Less common effects can include nasal congestion, cough, decreased appetite, and dry mouth [1.2.2]. The long-term safety of ashwagandha has not been well-studied, and most clinical trials are limited to three months of use [1.3.4, 1.5.4].
Conclusion
While ashwagandha is a popular herbal supplement with a long history of use, it is not appropriate for everyone. Individuals who are pregnant, breastfeeding, have autoimmune or thyroid disorders, are preparing for surgery, or have liver problems should avoid this herb. Furthermore, its potential to interact with a wide range of common medications—including sedatives, immunosuppressants, and drugs for diabetes and high blood pressure—warrants extreme caution. Always consult with a healthcare professional before adding ashwagandha or any other supplement to your regimen to ensure it is a safe choice for your specific health profile.
For more information, you can visit the National Center for Complementary and Integrative Health (NCCIH).
