Does ashwagandha help hair growth? What the research does and doesn't show

One placebo-controlled trial found a standardized ashwagandha extract improved several hair density and growth measures over 75 days, in adults with self-reported hair loss or skin concerns. It's a real, randomized result — and also a single trial, funded by the manufacturer of the extract ingredient it tested, using a form different from root powder. No trial has tested oral ashwagandha in people with a diagnosed hair-loss condition.

What the evidence doesn't support

It doesn't support ashwagandha as a treatment for androgenetic alopecia, telogen effluvium, or any diagnosed hair-loss condition — no trial enrolled a diagnosed population, only people who reported hair loss or skin concerns themselves. It doesn't support root powder specifically, since the one relevant trial used a standardized extract. And it doesn't support ashwagandha causing hair loss either — no trial has reported that as a side effect, in either direction.

What the trials found

The one trial directly testing this is a randomized, double-blind, placebo-controlled study in adults aged 18-60 who reported hair loss or skin conditions, comparing 600 mg/day of a standardized root extract (300 mg twice daily) against placebo for 75 days. Hair was assessed with TrichoScan imaging, a real biometric measurement method, and the extract group showed significantly greater improvement in hair density, growth rate, and the ratio of growing to resting hair follicles than placebo, along with better scores on a hair-specific quality-of-life questionnaire. No adverse events were reported.

Two things are worth weighing alongside that result. First, the study was funded by the manufacturer of the extract ingredient used — not disqualifying on its own, but a real conflict of interest to factor in when reading a positive result. Second, participants were adults who reported hair loss or skin concerns rather than people with a diagnosed condition like androgenetic alopecia confirmed by a dermatologist, so it's a milder and less-defined population than "hair loss" might suggest. No trial has tested plain root powder, the form most root-powder capsule products contain, for any hair-related outcome.

Separately, two documented ashwagandha effects are more likely to connect to hair than a direct mechanism: measurable reductions in cortisol in several trials, and a measurable rise in thyroid hormones in one trial of people with an underactive thyroid. Both chronic stress and thyroid dysfunction are established causes of hair shedding in the broader medical literature — which means if ashwagandha does anything for someone's hair, an indirect route through stress or thyroid hormones is at least as plausible as a direct one, and neither has been tested as the actual mechanism.

Questions people ask

Does ashwagandha help with hair growth?

One placebo-controlled, manufacturer-funded trial found improved hair density and growth measures over 75 days with a standardized extract, in people with self-reported (not diagnosed) hair loss. That's a real but limited result — one trial, one funding source, one form.

Can ashwagandha cause hair loss?

No trial has reported hair loss as a side effect. Ashwagandha's documented effect on thyroid hormones is worth knowing about if a thyroid imbalance — which can affect hair — is already a concern; see our ashwagandha and thyroid review.

How would I use ashwagandha for hair growth?

The one trial with a positive result used 600 mg/day of a standardized extract for 75 days — not root powder, and not a dose or timeline this page can turn into a general recommendation from a single industry-funded study.

Is ashwagandha good for hair thinning?

The same trial and the same caveats apply: one study, self-reported (not diagnosed) hair concerns, an extract rather than root powder, and funding from the ingredient's manufacturer.

When to talk to a doctor

Sudden, patchy, or rapidly progressing hair loss is worth a dermatologist's evaluation — it can have causes (thyroid disease, iron deficiency, autoimmune conditions, medication side effects) that a supplement wouldn't address. Ashwagandha is not a treatment for a diagnosed hair-loss condition. If you have a thyroid condition or take thyroid medication, talk to a doctor before adding ashwagandha, given its documented effect on thyroid hormones.

Related reading: ashwagandha and your thyroid, ashwagandha and cortisol, and what ashwagandha does for women.