What ketoconazole is, why it shows up in hair-loss shampoo routines, and what the research on it actually measured.
Ketoconazole is an antifungal. In the United States it is sold over the counter at 1% in Nizoral A-D, where it is the declared active ingredient for dandruff, and at 2% by prescription.
It became a hair-loss ingredient because of a small body of research suggesting it does more on the scalp than control yeast. The study people cite most is from Piérard-Franchimont and colleagues, published in Dermatology in 1998. Men with early vertex thinning used a 2% ketoconazole shampoo two to four times a week for 21 months. Hair density rose in the ketoconazole group and fell in a small group using a plain shampoo. A second, very small arm compared the shampoo with 2% minoxidil and found similar changes in hair shaft diameter after six months.
Those studies are small, and the minoxidil comparison used a lower dose than doctors prescribe today. A 2020 systematic review in Dermatologic Therapy pulled together seven studies, five of them in people, and called topical ketoconazole a promising add-on or alternative that still needs larger randomized trials.
Most routines use a ketoconazole shampoo two to four times a week, leaving the lather on the scalp for three to five minutes before rinsing. On the other days, a gentler shampoo keeps the scalp from drying out.
Only two shampoos in our comparison contain ketoconazole. Nizoral A-D is the cheapest, in a sulfate base, with nothing else aimed at thinning hair. Regenepure DR combines ketoconazole with saw palmetto, caffeine, emu oil and niacin in a base with no sulfates, which is why it is our top pick.
