Abstract: The present disclosure relates to a method for the conditioning of keratinous fibers comprising applying to dry or wet fibers, a cosmetic composition comprising at least one entity chosen from lysine-derived compounds of formula (I), and the salts and/or solvates thereof. The disclosure also relates to a cosmetic composition for conditioning keratinous fibers comprising, in a cosmetically acceptable medium, at least one entity chosen from lysine-derived compounds of formula (I) and the salts and/or solvates thereof and at least one cosmetic adjuvant. The disclosure also relates to a mixture of at least one entity chosen from lysine-derived compounds of formula (I) and the salts and/or solvents thereof.