Dermatologists Weigh In: Can Nizoral Really Treat Hair Loss?

A $17 bottle of Nizoral is the centerpiece of a viral hair-loss hack — but five board-certified dermatologists say the science behind ketoconazole shampoo as a regrowth treatment is, at best, modest.

The social media conversation centers on ketoconazole, the antifungal ingredient in Nizoral, the main over-the-counter dandruff shampoo featuring it in the United States. Dermatologists including Heather Kornmehl, Neera Nathan and Joyce Kim have discussed it in their own videos; Dr. Kim rated it 7.5/10 as a hair-loss treatment option. Shereene Idriss claimed it "helps fight that pesky testosterone that causes you to lose your hair."

What does the evidence actually show?

"Ketoconazole is an antifungal we use for dandruff and seborrheic dermatitis," says Kautilya Shaurya, MD, a board-certified dermatologist in New York City. He acknowledges "modest evidence" that it can help with hair loss. A frequently cited 1998 study found that men using 2% ketoconazole shampoo several times a week "saw gains in hair density and thickness roughly comparable to 2% minoxidil."

That study was small and lacks follow-up research, Dr. Shaurya notes. The FDA has not approved ketoconazole for hair loss, and dermatologists do not typically prescribe it as a standalone treatment. In the U.S., only the 1% formula is available over the counter; stronger concentrations require a prescription. Caren Campbell, MD, of San Francisco adds that no strong research supports its efficacy in women.

Most studies are 30 or more years old, likely because, as Dr. Campbell puts it, "we have better medications to use with a bigger impact [on hair loss]." Dr. Shaurya explains that ketoconazole is a well-established generic drug — just not for this purpose: "It has never gone through the large trials the FDA would require to approve it for hair loss."

Why do some users see regrowth?

Menopausal hair loss is driven by hormonal shifts, particularly declining estrogen, explains Dawn Queen, MD, of New York City. Falling estrogen increases androgen activity, causing thinning in genetically predisposed women. Viral videos claim ketoconazole blocks DHT, the androgen central to follicle shrinkage. Dr. Queen counters that anti-androgen effects appeared in a lab study only: "Clinically, there is limited evidence that ketoconazole shampoo meaningfully reduces DHT levels in the scalp."

Kseniya Kobets, MD, director of cosmetic dermatology at Montefiore Einstein Advanced Care, notes "most women with pattern thinning don't have elevated androgens" and that "DHT doesn't explain everything." She also questions the delivery method: "We don't know how much DHT blockade a rinse-off shampoo delivers."

Real results likely come from scalp health, Dr. Shaurya says. Ketoconazole reduces Malassezia yeast, calms inflammation around follicles and treats seborrheic dermatitis, which can drive shedding. Jenna Queller, MD, of Palm Beach cautions that less visible shedding is not the same as regrowth — which is why products claim "fuller looking hair," not "reverses hair loss," a claim reserved for FDA-approved drugs.

What are the risks?

Overuse can leave hair dry and brittle — a particular concern for menopausal women and people with textured, damaged or chemically treated hair. Dr. Queller advises following with moisturizing shampoo, conditioner or a mask. Reports that the shampoo causes hair loss are unproven: "reports alone don't establish that ketoconazole directly causes hair loss," she says.

Proven treatments remain topical minoxidil, low-dose oral minoxidil, and, in select patients, spironolactone or finasteride, plus PRP injections and low-level laser therapy, according to Dr. Queen.

"The problem with TikTok is that it removes the 'diagnosis' step," says Dr. Campbell. As Dr. Kobets puts it: "Social media can start the conversation; your diagnosis should guide the treatment."