Zinc Pyrithione (CAS 13463-41-7) is an antibacterial and antifungal used in cosmetics mainly in anti-dandruff shampoos because it has a targeted effectiveness in fighting Malassezia, a fungus naturally present on the skin and scalp, but responsible, in case of increase of colonies, for dandruff.
The structure of the developed molecule was rationally borrowed from aspergillic acid, a naturally occurring antimicrobial.
Currently in cosmetic products the use of Zinc Pyrithione is foreseen as a preservative (therefore present in All.V of Reg.1223 at no.8, maximum concentration of use 1% in products for hair/beard and moustache and 0.5% in other products, to be used in both cases only in rinse-off products, forbidden in products intended for oral hygiene) and, for purposes other than inhibiting the development of microorganisms in the product, it is however regulated and present in All.III of Reg.1223 at no.101 with maximum concentration of use 0.1%, in products for hair/beard and moustache, not to be rinsed off.
In 2017, Zinc Pyrithione was submitted by Sweden for a proposal for harmonized classification and labeling as a developmental toxicant and the RAC (Risk Assessment Committee) of ECHA in 2018 adopted an opinion in which it confirmed the classification of this substance as Repr. 1B. If this opinion is confirmed, it could lead to the inclusion of the substance in Omnibus Act IV with application of the new classification from the end of 2022.
Article 32 of Regulation 1223/2009 on cosmetic products prohibits the use of substances classified as carcinogenic, mutagenic or toxic for reproduction (CMR), category 1A, 1B and 2, according to the CLP regulation.
However, there are cases in which the use of CMR substances is allowed following specific evaluations carried out by SCCS certifying their safety for use in cosmetics and applying the exemption process foreseen by art. 15 paragraph 2 of the Cosmetic Regulation.
SCCS after collecting all the information and analyzed also the data coming from the Food Unit related to the presence and concentration of the substance in food (some Allium species) published in March 2020 the Final opinion SCCS/1614/19 "OPINION ON Zinc Pyrithione (ZPT) (CAS No 13463-41-7) - Submission III".
In particular, the industry has decided to defend the use of Zinc Pyrithione in anti-dandruff rinse-off products at the maximum concentration of 1%, leaving out the defense in leave-on hair products at 0.1%.
SCCS, taking into account the scientific data provided, concluded, consistent with Article 15 of Regulation (EC) No. 1223/2009 (d) (i.e., "overall exposure from other sources"), that zinc pyrithione (ZPT) is SAFE when used as an anti-dandruff agent in rinse-off hair products up to a maximum concentration of 1%.
The SCCS findings will be an essential part of the possible exemption as a CMR.