The present invention relates to a combination product a cosmetic composition comprising a first cosmetic composition comprising the glucosamine or one of its salts, a second cosmetic composition comprising of the hyaluronic acid and a third cosmetic composition comprising collagen, a cosmetic composition comprising the glucosamine or one of its salts, of the hyaluronic acid and of the collagen, their uses, in particular for the synthesis of hyaluronic acid and thus to combat skin ageing affecting the fibroblasts and the dermis, as well as a cosmetic process employing these products of the combinations and compositions.