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Public Health
Expert opinion

Revision of the opinion on 1-Hexyl 4,5-Diamino Pyrazole Sulfate (A163)

Final Opinion


Publication date
15 December 2015
Scientific Committee on Consumer Safety (SCCS)


SCCS members: Qasim Chaudhry, P. Coenraads, M. Dusinska, W. Lilienblum, E. Nielsen, T. Platzek, S. C. Rastogi, Ch. Rousselle, Ja. van Benthem
External experts: A. Bernard, L. Bodin, J. Duus-Johansen, J. Ezendam, A. Giménez-Arnau, E. Mirkova,E. Panteri, T. Vanhaecke
Contact:SANTE-C2-SCCSatec [dot] europa [dot] eu (SANTE-C2-SCCS[at]ec[dot]europa[dot]eu)
On request from: European Commission
SCCS Number: SCCS/1562/15
Adopted on: 15 December 2015

Conclusion of the opinion:

1. In light of the data provided, does the SCCS consider 1-Hexyl-1H-pyrazole-4,5-diamine hemisulfate (A163) safe when used as an oxidative hair colouring agent (precursor) in oxidative hair dye formulations at a maximum on-head concentration of 1.0%?

The SCCS is of the opinion that 1-hexyl 4,5-diamine pyrazole sulfate is safe for use in oxidative hair dye formulations with an on-head concentration of maximum 1.0% taken into account the scientific data provided.

2. Does the SCCS have any further scientific concerns with regard to the use of 1-Hexyl-1Hpyrazole- 4,5-diamine hemisulfate (A163) in cosmetic products?

1-hexyl 4,5-diamine pyrazole sulfate is a moderate skin sensitiser.


SCCS, scientific opinion, A163, 1-Hexyl 4,5-Diamino Pyrazole Sulfate, Regulation 1223/2009, CAS 1361000-06-7

Opinion to be cited as:

SCCS (Scientific Committee on Consumer Safety), Opinion on A163, 25 June 2015, SCCS/1562/15, revision of 15 December 2015.