Piroctone olamine

Anti-dandruff agent0.5–1%

A widely used scalp-care ingredient that helps control visible flaking; a common alternative to zinc pyrithione.

What it is

Piroctone olamine has been used in shampoos and scalp products for more than 30 years to keep a flaky scalp in check. With regular use, flakes are visibly reduced and the scalp feels cleaner and more comfortable.

Good for

Flaky scalpOily scalpVisible flakes

How it works

Visible flaking is linked to Malassezia, a yeast found on most scalps. Piroctone olamine binds iron the yeast needs, slowing it down so the scalp sheds fewer visible flakes. In a shampoo it must stay on the scalp long enough to work, so delivery and contact time matter.

Ratings

Evidence

4/5

Several shampoo trials show results comparable to zinc pyrithione.

Gentleness

4/5

Low irritation at the levels used in rinse-off products.

Formulation difficulty

3/5

Dissolves well in surfactants, but less so at acidic pH.

Cost

3/5

Mid-priced and a noticeable share of shampoo cost at 0.5–1%.

Popularity

4/5

Widely used for over 30 years and now a common alternative to zinc pyrithione, banned in EU cosmetics since 2022.

Pairs and cautions

Pairs well with

In a routine. Pairing in one formula depends on matching pH windows.

Take care with

Strongly acidic basesLower solubility

Formulations it suits

Shampoo Conditioner and hair mask

Packaging

Regional considerations

Australia	Unscheduled. Anti-dandruff shampoos stay cosmetics only if they claim to control dandruff by cleansing, moisturising, exfoliating or drying the scalp; antifungal claims make them therapeutic goods.
European Union	The EU preservatives annex caps it at 1% in rinse-off and 0.5% in all other products, so plan leave-on scalp tonics at 0.5% or less. ASEAN sets the same limits.
United States	Not an active in the US anti-dandruff OTC monograph. FDA asked for data in 2004 but never added it, so US products cannot make anti-dandruff drug claims based on it.

In the lab

Specifications

Typical use level

0.5–1%0525%

pH window

pH 4–102 acid7 neutral10 alkaline

Solubility

Alcohol-solubleWater-dispersible

Sensitive to

LightMetal ionsLow pHHeat

Anti-dandruff shampoos use 0.5–1% and leave-on scalp care 0.1–0.5%. At 0.05–0.1% it works as a preservative booster.

INCI	Piroctone Olamine
Also known as	Octopirox, PO
Origin	synthetic

Lab notes

Solubility and phase

Surfactant phase, glycols or alcohol–water, as it is poorly soluble in water and many oils. It dissolves best near neutral pH, so shampoos usually sit at 5–7.

Stability

Keep processing below 80 °C and avoid prolonged heating, following supplier guidance. Even 1 ppm iron forms a visible yellow complex that usual chelators do not prevent, so limit iron and copper in raw materials and equipment.

Regulatory, Australia

Cosmetic ingredient in Australia and not listed in the Poisons Standard. Zinc pyrithione has been banned from EU cosmetics since March 2022.

Claims to take care with

Anti-dandruff products stay cosmetic only if claims are limited to controlling dandruff by cleansing, moisturising, exfoliating or drying the scalp (TGA Excluded Goods). 'Antifungal', itch-relief or 'treats seborrhoeic dermatitis' claims make it therapeutic.