The invention relates to a cosmetic composition comprising at least one cosmetically acceptable excipient and from 0.01 to 1% by weight, preferably from 0.05 to 0.6%, and more preferably from 0.1 to 0.3% by weight of the combination of an extract of the brown alga Laminaria digitata, of a Saccharomyces hydrolysate and of ascorbic acid or one of its esters, the percentage being expressed by dry weight.The combination of active agents of the invention for which a synergistic effect with regard to the synthesis of the procollagen I has been shown also produces an advantageous effect with regard to other markers of aging.