BACKGROUND
Hydroxypropyl p-phenylenediamine (CAS/EC No. 73793-79-0/827-723-1) with the chemical name “3-(2,5-diaminophenyl)propan-1-ol” and its dihydrochloride salt with the chemical name “3-(2,5-diaminophenyl)propan-1-ol dihydrochloride salt” are not currently regulated under the European Cosmetics Regulation (EC) No. 1223/2009. These substances are used as cosmetic ingredients with the functions of hair dyeing.
In 2018, the European Commission was requested to evaluate the safety of Hydroxypropyl p-phenylenediamine and its dihydrochloride salt (A165) as hair dyes in cosmetic products. In its opinion (SCCS/1608/19), the SCCS concluded that ‘in light of the data provided, Hydroxypropyl p-phenylenediamine and its dihydrochloride salt are not safe when used in oxidative hair colouring products due to potential genotoxicity’. In addition, the SCCS noted that ‘a mild to moderate eye irritation potential of the substances cannot be excluded’.
In June 2022, the European Commission received a new request to re-evaluate the safety of these substances after receiving additional data from the applicant which addressed the issue of genotoxicity. In this request, Hydroxypropyl p-phenylenediamine and its dihydrochloride salt (A165) were intended to be used in oxidative hair colouring products up to a maximum on-head concentration of 2%.
WHAT’S NEW?
In light of the information provided, the SCCS concluded that Hydroxypropyl p-phenylenediamine and its dihydrochloride salt are safe when used in oxidative hair colouring products up to a maximum on-head concentration of 2%.
Additionally, the SCCS considered that Hydroxypropyl p-phenylenediamine and its dihydrochloride salt have a mild to moderate eye irritation potential and, based on animal data, a moderate skin sensitiser potential. These concerns are aligned with the ones presented in the previous opinion in October 2019.
References:
Scientific Committee on Consumer Safety (SCCS) – Opinion on Hydroxypropyl p-phenylenediamine and its dihydrochloride salt (A165) (CAS/EC No. 73793- 79-0/827-723-1 and 1928659-47-5/-), preliminary version of 26 October 2023, final version of 28 February 2024, SCCS/1659/23
