Abstract: The present invention concerns the use of a polypeptide comprising a sequence having at least 90% identity with all or part of BNIPXL?, for cosmetic or therapeutic applications, in the treatment or prevention of premature canities in humans, said portion comprising at least 30 amino acids, as well as the use, for the same purpose, of a molecule comprising a RNAi sequence having at least 90% identity with all or part of the cDNA sequence of BNIPXL?, said part comprising at least 18 nucleotides. The invention also concerns methods for screening molecules modulating the expression of a gene coding for BNIPXL-beta and molecules modulating the activity of the BNIPXL-beta polypeptide, in order to identify an agent for use for cosmetic or therapeutic purposes in the field of pigmentation. The invention also encompasses various uses of molecules which may be identified by these methods.