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Antimicrobials

Piroctone olamine

Also listed as piroctone ethanolamine salt

An antifungal that replaced zinc pyrithione in many European dandruff shampoos. Matched it in a manufacturer-run trial; not an approved US dandruff drug.

Moderate evidenceTypical strength: 0.5-1% in rinse-off shampoos (EU maximum 1% rinse-off, 0.5% leave-on)

What it is

Piroctone olamine is an antifungal that targets the Malassezia yeast behind dandruff. It is permitted in EU cosmetics (up to 1% in rinse-off products and 0.5% in others) and became the main European anti-dandruff active after zinc pyrithione was banned in 2022.

It is not among the FDA's approved dandruff actives, so US products cannot make a dandruff-treatment drug claim based on it alone; it appears in US products as a cosmetic ingredient or alongside an approved active.

How strong is the evidence?

Moderate evidence

A split-head trial found a shampoo with 0.5% piroctone olamine plus 0.45% climbazole reduced dandruff as well as 1% zinc pyrithione; it was run by a manufacturer and tested a combination. Lab data show solid antifungal activity. Independent trials are few.

What it's used for, checked

Controls dandruff

Holds up

Comparable to zinc pyrithione in manufacturer-run trials.

Treats hair loss

Unproven

Not established.

Works well with

  • zinc-pyrithione

Who should be careful

  • Generally well tolerated; keep out of the eyes.
  • If flaking persists or the scalp is red and inflamed, see a clinician about seborrhoeic dermatitis or psoriasis.

The studies

Every citation is checked against its PubMed record.

  1. Efficacy of a piroctone olamine/climbazol shampoo in comparison with a zinc pyrithione shampoo in subjects with moderate to severe dandruff.
    Schmidt-Rose T, Braren S, Folster H, et al. · Int J Cosmet Sci · 2011 · RCT (split-head, manufacturer-run)

    A shampoo with 0.5% piroctone olamine plus 0.45% climbazole reduced dandruff as well as a 1% zinc pyrithione shampoo in a split-head study, with similar antifungal activity in the lab. Conducted by the manufacturer's research team.