Guide
Ashwagandha side effects
The most commonly reported side effects in ashwagandha trials are stomach upset, loose stools, nausea and drowsiness. Rare, documented case reports describe liver injury, including at close to a typical label dose.
The side effects most consistently reported in ashwagandha trials are stomach upset, loose stools, nausea and drowsiness. A rarer but documented concern is liver injury, described in case reports at doses including close to a typical label amount. Popular questions like "emotional blunting" or vivid dreams haven't actually been measured in any trial we reviewed.
Common side effects reported in trials
Across the trials in this file, the side effects that show up most are digestive: stomach upset, loose stools and nausea. Drowsiness is the other consistently reported effect — expected, since ashwagandha has shown sedative-type activity in research (see when is the best time to take ashwagandha? if that's relevant to when you take it). In one escalating-dose tolerability study, 17 of 18 healthy adults tolerated doses up to 1,250 mg/day of a concentrated extract without incident; one participant was withdrawn at the lowest dose tested for increased appetite, increased libido, and hallucinogenic effects with vertigo. That's a single case in a small, uncontrolled study, not a typical reaction, but it's the kind of rare effect worth knowing exists.
Liver injury: rare, but documented
Case reports describe liver injury in adults taking ashwagandha capsules, including one man taking 1,350 mg/day — almost exactly a typical label dose — for 6 months, and a healthy 22-year-old woman who developed injury just 30 hours after starting. Both a formal causality assessment and the researchers' own conclusions scored these "probable," not certain, and case reports can't tell us how often this happens across everyone who takes it. Stop and see a doctor for jaundice, unusually dark urine, itching, or pain under the right ribs. The full picture is in is ashwagandha bad for your liver?
Thyroid effects
A placebo-controlled trial found that 600 mg/day of ashwagandha extract measurably raised T3 and T4 and lowered TSH over 8 weeks in adults with a diagnosed thyroid condition. If you have a thyroid condition or take thyroid medication, that's a real effect to ask a doctor about before starting — not a benefit we claim in either direction.
Questions people ask
Will ashwagandha make you sleepy?
It can. Drowsiness is one of the more consistently reported side effects in ashwagandha research, and ashwagandha has shown sedative-type activity in laboratory studies. If it makes you drowsy, that's worth factoring into when you take it — see when is the best time to take ashwagandha?
What are the side effects of ashwagandha?
Most commonly: stomach upset, loose stools, nausea and drowsiness. Less commonly, and reported in a single small study: increased appetite, increased libido, and vertigo with hallucinogenic effects at the lowest dose tested. Rare but documented: liver injury, covered in detail above.
Does ashwagandha make you emotionless, or numb?
No trial we reviewed measured emotional blunting or numbness as an outcome, so we can't confirm or rule it out from the research. It's a commonly searched question, but it's an anecdotal one at this point, not a documented trial finding.
Why does ashwagandha make me angry, or affect my mood?
None of the trials in this file measured mood changes like irritability or anger as an outcome. If you notice a mood change after starting ashwagandha, that's worth mentioning to a doctor rather than assuming it will pass.
Can you be allergic to ashwagandha?
Withania somnifera is in the nightshade (Solanaceae) family with tomato, potato, eggplant and bell pepper. If you have a known nightshade sensitivity, use caution. General allergic reactions to any supplement ingredient are possible; stop taking it and see a doctor if you notice hives, swelling or difficulty breathing.
Can ashwagandha cause dizziness?
One escalating-dose study reported vertigo, alongside hallucinogenic effects, in one of 18 participants at the lowest dose tested (750 mg/day of a concentrated extract). It's a documented but rare report from a single small study, not a common finding across the research.
Sources
- Exploratory study to evaluate tolerability, safety, and activity of Ashwagandha (Withania somnifera) in healthy volunteers In 18 healthy adults, an 8:1 ashwagandha extract at 750-1,250 mg/day for 4 weeks was mostly well tolerated, with one withdrawal for adverse effects; there was no placebo group to compare against.
- Efficacy of Brimhana Nasya and Ashwagandha (Withania somnifera (L.) Dunal) root powder in primary insomnia in elderly male: A randomized open-label clinical study In 27 elderly men with diagnosed insomnia, 6 g/day of ashwagandha root powder for 4 weeks improved self-reported sleep versus their own baseline, with no placebo group.
- Herb-Induced Liver Injury by Ayurvedic Ashwagandha as Assessed for Causality by the Updated RUCAM: An Emerging Cause Two adults taking 450 mg ashwagandha capsules (one at 1,350 mg/day) developed liver injury judged 'probably' caused by the supplement, resolving after stopping it.
- Ashwagandha-Induced Hepatic Injury: A Case Report A healthy 22-year-old developed liver injury 30 hours after starting ashwagandha capsules; dose not reported.
- Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients: A Double-Blind, Randomized Placebo-Controlled Trial In 50 adults with subclinical hypothyroidism, 600 mg/day of ashwagandha root extract for 8 weeks measurably shifted TSH, T3 and T4 versus placebo.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
