Ashwagandha is generally safe for most women when taken short term, meaning up to about three months. Beyond that window, there isn’t enough research to draw firm conclusions about long-term safety. The herb does carry specific risks for women who are pregnant, breastfeeding, or managing thyroid conditions, so “safe” comes with important caveats depending on your situation.
Short-Term Use Is Well Tolerated
Across numerous clinical trials, ashwagandha has been well tolerated by participants for up to three months. The most common side effects are mild: stomach upset, loose stools, nausea, and drowsiness. These tend to resolve on their own and don’t typically require stopping the supplement. Most studies have used daily doses ranging from 450 to 1,350 mg, though there’s no universally agreed-upon dose for women specifically.
Ashwagandha is classified as a dietary supplement, not a drug, which means the FDA does not review it for safety or effectiveness before it hits store shelves. Manufacturing standards are less strict than for pharmaceuticals, so product quality can vary between brands. If you decide to try it, choosing a product that has been third-party tested helps reduce the risk of contaminants or inaccurate labeling.
Liver Injury Is Rare but Real
A small number of liver injury cases have been linked to ashwagandha supplements. The NIH documents five cases (including two women, ages 21 to 62) where people taking 450 to 1,350 mg daily for one week to four months developed signs of liver damage: yellowing skin, nausea, fatigue, and abdominal discomfort. These cases are rare relative to how widely the supplement is used, but they’re worth knowing about. The German Federal Institute for Risk Assessment specifically advises people with pre-existing liver disease to avoid ashwagandha entirely.
Effects on Stress and Cortisol
The most popular reason women take ashwagandha is stress relief, and there is evidence behind this use. A meta-analysis found that ashwagandha reduced cortisol (the body’s primary stress hormone) by roughly 12% to 16% compared to placebo. That’s a modest but measurable drop. However, the same analysis noted that perceived stress didn’t always improve alongside the cortisol numbers, meaning the hormonal change doesn’t automatically translate into feeling calmer.
Thyroid Function Can Shift Significantly
This is one of the most important safety considerations for women, since thyroid disorders are far more common in women than men. Ashwagandha appears to actively boost thyroid hormone production. In one eight-week study of 50 people with underactive thyroids, 600 mg of ashwagandha root extract daily increased T3 levels by 41.5%, T4 levels by 19.6%, and lowered TSH by 17.5% compared to placebo.
If you have an underactive thyroid and are already taking thyroid medication, ashwagandha could push your levels higher than intended. The interaction with levothyroxine (the most commonly prescribed thyroid medication) is classified as moderate, meaning it can alter how the drug works. If you have an overactive thyroid or Graves’ disease, ashwagandha could make things worse. And if your thyroid is healthy, regularly taking a supplement that meaningfully shifts thyroid hormones is something to approach with awareness, not casually.
Pregnancy and Breastfeeding
Ashwagandha should be avoided during pregnancy. This isn’t just a cautious “we don’t have enough data” warning, though that’s true too. The herb has historically been used as an abortifacient (a substance to induce miscarriage), which is why both the NCCIH and the German Federal Institute for Risk Assessment flag it as a concern. There is also evidence that it affects sex hormones and the endocrine system broadly, adding further reason to steer clear while pregnant or trying to conceive.
The same applies to breastfeeding. No safety data exists for nursing mothers, and the potential hormonal effects make it a poor candidate for “probably fine.” Both major health agencies recommend against use during this period.
Hormonal Effects Beyond the Thyroid
Ashwagandha contains antioxidants that may mimic estrogen activity in the body. This is part of why some research suggests it could help with perimenopausal symptoms. One study found that women taking ashwagandha extract saw a 23.5% improvement in menopause symptom scores (covering hot flashes, insomnia, and other physical symptoms) compared to 10.9% in the placebo group.
That estrogen-mimicking quality cuts both ways. For perimenopausal women with declining estrogen, a mild boost might be welcome. For women with estrogen-sensitive conditions, or those on hormonal birth control or hormone replacement therapy, adding a supplement that influences estrogen activity introduces unpredictability. The research on how ashwagandha interacts with oral contraceptives specifically is thin, which itself is a reason for caution.
Drug Interactions to Watch
Beyond thyroid medications, ashwagandha can interact with several drug categories that women commonly use:
- Diabetes medications: Ashwagandha may lower blood sugar, which could amplify the effects of glucose-lowering drugs.
- Blood pressure medications: The herb may lower blood pressure on its own, risking an excessive drop when combined with antihypertensives.
- Sedatives and anti-anxiety medications: Because ashwagandha can cause drowsiness, combining it with sedatives or sleep aids may increase that effect.
- Immunosuppressants: Ashwagandha may stimulate certain immune responses, potentially working against drugs designed to suppress the immune system. Women with autoimmune conditions like lupus or rheumatoid arthritis should avoid it.
Who Should Skip It
The list of women who should avoid ashwagandha is more specific than the list of those who can safely try it. You fall into the “skip it” category if you are pregnant or breastfeeding, have a thyroid disorder (especially if medicated), have an autoimmune condition, have liver disease, or are scheduled for surgery (ashwagandha may affect sedation and blood pressure during procedures). If you’re taking any of the medications listed above, the potential for interaction makes the risk-benefit math unfavorable without medical guidance.
For women outside those groups who want to try ashwagandha for stress or sleep, the existing evidence supports short-term use at commonly studied doses as reasonably safe. Keeping use to three months or less, starting at a lower dose, and paying attention to how your body responds (particularly digestive changes or unusual fatigue) is a practical approach.