Who Should Not Take Ashwagandha? Key Risks and Who Should Avoid It

When you hear "ashwagandha," you might think of a miracle herb that helps with stress, sleep, and energy. And for many people, it does. But ashwagandha, an adaptogenic herb used in Ayurveda for over 3,000 years to help the body manage stress. Also known as Withania somnifera, it’s powerful—but not safe for everyone. Just because it’s natural doesn’t mean it’s harmless. Some people can have serious reactions, and skipping it might be the best health choice.

One group that needs to be extra careful: people with thyroid conditions, including hyperthyroidism or those taking thyroid medication. Ashwagandha can boost thyroid hormone levels, which sounds good—until it pushes an overactive thyroid even higher. A 2018 study in the Journal of Clinical Endocrinology & Metabolism found it raised T4 levels in people with subclinical hypothyroidism. For someone already on levothyroxine, that could mean heart palpitations, weight loss, or anxiety. If your thyroid is already out of balance, ashwagandha might make things worse, not better.

Then there’s autoimmune diseases, like rheumatoid arthritis, lupus, or multiple sclerosis. Ashwagandha stimulates the immune system. That’s great if you’re fighting off a cold. But if your body is already attacking itself, that immune boost can trigger flare-ups. People with these conditions often feel fine on meds—until they add ashwagandha and suddenly feel worse. It’s not a myth. It’s science.

What about pregnancy? If you’re expecting, skip it. There’s not enough solid research, but animal studies show it might cause early contractions. Same goes for breastfeeding—no clear safety data. And if you’re on medications for high blood pressure, diabetes, or sedatives, ashwagandha can interact. It lowers blood sugar and blood pressure. That’s helpful for some, but if you’re already on meds, you could end up with dizziness, fainting, or even hypoglycemia.

And don’t assume it’s safe just because it’s sold in health stores. Supplements aren’t regulated like drugs. Two bottles labeled "ashwagandha" can have wildly different amounts of active compounds—or even contaminants. If you’ve had liver issues, kidney problems, or a history of hormone-sensitive cancers (like breast or prostate), talk to your doctor first. Ashwagandha isn’t the villain. But it’s not a one-size-fits-all solution either.

So who should avoid it? Anyone with thyroid problems, autoimmune conditions, or on certain meds. Pregnant or breastfeeding people. People with low blood pressure or low blood sugar. And anyone who’s tried it and felt off afterward. You don’t need to take everything that’s trendy. Sometimes the smartest health move is saying no.

Below, you’ll find real stories and facts from people who’ve dealt with these issues—not guesses, not marketing. Just clear, practical info on who ashwagandha helps, who it hurts, and what to do instead.