Who Should Avoid Ashwagandha? Risks, Side Effects, and Who’s at Risk

When you hear about ashwagandha, a traditional Ayurvedic herb used for stress, energy, and sleep. Also known as Withania somnifera, it’s one of the most popular herbal supplements today. But just because it’s natural doesn’t mean it’s safe for everyone. Many people take it without thinking twice—until they start feeling off. Some get dizzy. Others feel their heart racing. A few even end up in the doctor’s office because their thyroid went haywire. The truth? Ashwagandha isn’t harmless. It interacts with your body in powerful ways, and if you have certain health conditions, it can do more harm than good.

People with thyroid disorders, including hyperthyroidism or autoimmune thyroid disease should stay away. Ashwagandha can boost thyroid hormone levels, which sounds good—until you already have too much. One study in the Journal of Clinical Endocrinology & Metabolism showed patients with overactive thyroids saw their T3 and T4 levels rise after taking it. That’s not a tweak. That’s a medical red flag. Then there’s autoimmune diseases, like lupus, rheumatoid arthritis, or multiple sclerosis. Ashwagandha stimulates the immune system. For someone with an overactive immune system, that’s like pouring gasoline on a fire. It can trigger flare-ups, worsen joint pain, or make fatigue worse.

If you’re on blood pressure medication, like ACE inhibitors or beta-blockers, or diabetes drugs, such as metformin or insulin, you’re playing with fire. Ashwagandha lowers blood pressure and blood sugar. Take it with your pills, and you might crash—literally. Dizziness, fainting, confusion. These aren’t side effects you want to test. Even if you’re healthy now, if you’re planning surgery, skip it. Ashwagandha can interfere with anesthesia and slow your heart rate during procedures. And if you’re pregnant or breastfeeding? No clear safety data exists. Why risk it?

It’s not just about what’s in the bottle. It’s about what’s in your body. If you’ve ever been told you have an overactive thyroid, high blood pressure, or an autoimmune condition, you’re not just someone who might benefit from ashwagandha—you’re someone who could be hurt by it. The same goes if you’re taking any prescription meds. This isn’t a supplement you can just add to your morning routine without checking first. Talk to your doctor. Bring up the label. Ask if it’s safe for you. Because the truth is, what helps one person can break another.

Below, you’ll find real posts from people who’ve dealt with herbal risks, thyroid issues, and the hidden dangers of supplements. Some of these stories aren’t about ashwagandha—but they’re about the same blind spots we all have when we assume natural equals safe. Read them. Learn. Then decide what’s right for your body.