On the back of an anti-dandruff shampoo bought in Europe in recent years, it is very likely that you will find one of these two names: Piroctone Olamine or Climbazole. Since 2022, when zinc pyrithione was banned in cosmetics, they have become the two key actives for combating dandruff.
In summary
- Both act on Malassezia, the scalp yeast involved in dandruff, reducing its proliferation.
- Piroctone olamine is permitted up to 1% in rinse-off products and 0.5% in other products. It is considered well tolerated.
- Climbazole is permitted as an anti-dandruff ingredient up to 2% in rinse-off shampoos.
- They work best together with other actives, such as keratolytics, and with a few minutes of contact time.
Article written by Elisa Avalle, founder of LeLang Skin Care and dermocosmetics specialist. Cover image generated with the support of artificial intelligence.
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Why actives against Malassezia are needed
Dandruff results from the interaction of three factors: a yeast that lives on all scalps, Malassezia; the sebum it feeds on; and a person's sensitivity, whose skin reacts by accelerating cell turnover. Reducing the amount of Malassezia is the most direct way to reduce flaking. The complete picture is in the guide to dry or oily dandruff.
Piroctone olamine
In the INCI, it is listed as Piroctone Olamine. It is a salt of a pyridone derivative, developed as an antimicrobial: it acts on yeast cells by interfering with iron absorption, which they need to grow.
- Where it is used: shampoos, usually between 0.5% and 1%, and scalp lotions, at lower concentrations.
- EU limits: up to 1% in rinse-off products and 0.5% in leave-on products.
- Tolerability: it is considered minimally irritating, one of the reasons it is so widely used.
- Efficacy: with the same formula, it is more effective when the concentration is toward the upper end of the permitted range.
Climbazole
In the INCI, it is Climbazole. It belongs to the azole family, the same as some antifungals used in medicine, and works by interfering with the synthesis of components of the yeast membrane.
- Where it is used: mainly in anti-dandruff shampoos.
- EU limits: Regulation (EU) 2019/698 permits it as an anti-dandruff ingredient at up to 2% in rinse-off shampoos. When used as a preservative, the limits are lower.
- Good to know: the most potent antifungal azoles, such as ketoconazole, are medicines, not cosmetics. Climbazole is the representative of this family permitted in cosmetic products.
They work better together
Piroctone olamine and climbazole are often found in the same shampoo. In a study of people with moderate to severe dandruff, a shampoo combining them produced results comparable to one based on zinc pyrithione, the reference active ingredient at the time.
In general, the most effective anti-dandruff shampoos combine active ingredients with different functions:
| Function | Examples |
|---|---|
| Against Malassezia | Piroctone olamine, climbazole, undecylenic acid derivatives |
| Loosen flakes | Salicylic acid, urea |
| Slow down cell turnover | Selenium disulfide |
| Soothe itching | Bisabolol, oat extracts |
The point is not just the active ingredient, but the contact time. A shampoo rinsed off immediately leaves the active ingredients only a few seconds to work. Leaving it on the scalp for a few minutes, or using a lotion that stays on the skin, makes a real difference.
What about zinc pyrithione?
Zinc pyrithione (Zinc Pyrithione) was the most widely used anti-dandruff ingredient for decades. Following its classification as a toxic substance for reproduction, it has been banned in cosmetics sold in the European Union since March 1, 2022, under Regulation (EU) 2021/1902. Anyone who finds it in the INCI of a product purchased outside the EU knows that it is no longer permitted in Europe.
How to recognize them on the label
- Piroctone Olamine: usually in the second half of the INCI, because the usage concentrations are low.
- Climbazole: it too is among the ingredients used in small amounts.
The position in the INCI does not indicate whether the concentration is adequate: below 1%, ingredients may be listed in any order. That is why the formula as a whole also matters, as does the advice of someone familiar with it.
Frequently asked questions
Can they be used every day?
In shampoos, yes, if the scalp tolerates them. They are generally used with every wash during the initial phase and then alternated with a gentle shampoo.
Are they suitable for a dry scalp?
They are not needed if the problem is dryness rather than dandruff. In that case, gentle cleansers and moisturizing products are more useful.
Are they safe?
At the concentrations permitted by the European Cosmetics Regulation, yes. The limits are set based on the assessments of the European Scientific Committee on Consumer Safety.
Sources for this article
- Regulation (EC) No. 1223/2009 on cosmetic products, Annexes III and V; Regulation (EU) 2019/698 (climbazole); Regulation (EU) 2021/1902 (zinc pyrithione).
- Schmidt-Rose T. et al. (2011). "Efficacy of a piroctone olamine/climbazole shampoo in comparison with a zinc pyrithione shampoo in subjects with moderate to severe dandruff". International Journal of Cosmetic Science, vol. 33, no. 3, pp. 276-282.
- Borda L.J., Wikramanayake T.C. (2015). "Seborrheic dermatitis and dandruff: a comprehensive review". Journal of Clinical and Investigative Dermatology, vol. 3, no. 2.
Where to continue: Dry or oily dandruff · Salicylic acid
