Who should not take ashwagandha?

Ask a doctor before taking ashwagandha if you're pregnant, nursing, under 18, have a thyroid condition or take thyroid medication, have an autoimmune condition, take a sedative or an immunosuppressant, or have liver disease. Documented case reports describe liver injury in adults taking ashwagandha capsules, including one at almost exactly a typical label dose — the single most important reason to stick to label directions and not assume more is safer.

Pregnancy, nursing and trying to conceive

Do not use if pregnant or nursing. This is a hard caution, not a use guideline — there's no dose or use guidance to give here, only: ask your doctor first, and this applies to trying to conceive as well.

Under 18

No dosing or use guidance exists for anyone under 18. Ask a doctor before giving ashwagandha to a teenager or child.

Liver injury: rare, but reported at a dose close to a typical label amount

A 2023 report describes two new cases of liver injury in adults taking ashwagandha capsules, scored "probable" by a formal causality assessment (RUCAM), alongside a review of previously published cases. In the first, a 36-year-old man taking 450 mg capsules three times a day — 1,350 mg/day, almost exactly a typical label dose — for 6 months developed hepatocellular-pattern liver injury. In the second, a 30-year-old woman taking 450 mg capsules for 45 days developed mixed-pattern injury. Both improved after stopping. A separate 2024 case report describes a healthy 22-year-old woman who developed liver injury just 30 hours after starting ashwagandha capsules; dose wasn't reported. Other published cases exist internationally, and one required a liver transplant.

Case reports like these can't tell us how often this happens across everyone who takes ashwagandha — they can't establish a rate. What they do establish is that it has happened, in healthy adults with no prior liver disease, at doses at or near what a typical label directs. If you have existing liver disease, ask a doctor before starting. Anyone taking ashwagandha should stop and see a doctor for jaundice (yellowing skin or eyes), unusually dark urine, itching, nausea, or pain under the right ribs.

Thyroid conditions and thyroid medication

A placebo-controlled trial gave 600 mg/day of ashwagandha extract to 50 adults with a diagnosed thyroid condition (subclinical hypothyroidism) for 8 weeks and found it measurably raised T3 and T4 and lowered TSH compared with placebo. That's real, demonstrated hormonal activity — a reason for caution, not a benefit claim. If you have a thyroid condition or take thyroid medication, ask a doctor before adding ashwagandha; the combination could push thyroid hormone levels further than intended.

Autoimmune conditions, immune-suppressing medication and upcoming surgery

Ashwagandha shows immune-stimulating activity in laboratory research, which could work against an immunosuppressant used for an autoimmune condition or after a transplant. Ask a doctor before combining the two. The same caution applies before surgery: ashwagandha has sedative-adjacent activity in research, which can interact with anesthesia, so tell your surgical team what supplements you're taking beforehand.

Sedatives and other CNS depressants

No dedicated trial has tested ashwagandha alongside a benzodiazepine or sleep medication, but ashwagandha has shown GABA-mimetic, sedative-type activity in research. Combining it with a sedative or sleep medication could add to drowsiness. Ask a doctor before combining them. See ashwagandha and medications: what to check for the full interaction list.

Known nightshade sensitivity

Withania somnifera is a member of the Solanaceae (nightshade) family, along with tomato, potato, eggplant and bell pepper. This isn't an established allergen warning the way a tree-nut or fish "contains" line is, but if you have a known nightshade sensitivity, use caution.

Questions people ask

Can ashwagandha cause liver damage?

Documented case reports describe it, including at close to a typical label dose, though case reports can't establish how common this is. See the liver-injury section above, and is ashwagandha bad for your liver? for the fuller research review.

Is ashwagandha safe for the liver and kidneys?

The liver-injury case reports above are the clearest documented concern; ask a doctor before starting if you have existing liver disease. We found no comparable case-report literature specific to kidney injury, but if you have kidney disease, ask a doctor before adding any new supplement.

Who should not take ashwagandha?

Anyone pregnant, nursing, or trying to conceive; anyone under 18; anyone with a thyroid condition, autoimmune condition or liver disease; and anyone taking thyroid medication, a sedative or an immunosuppressant, without first asking a doctor.

What should you not take with ashwagandha?

Thyroid medication, sedatives (including benzodiazepines and sleep medication) and immunosuppressants are the three categories with a plausible interaction. See ashwagandha and medications: what to check for detail on each.