The present invention relates to a novel use of compounds having the general formula (I): CH3(—CH═CH)n—R  (I) where n=from 2 to 7, and R is chosen from among: CHO, CH2OH, CH2O—CO—R′, CO—OR′, CO—O(−), where R′ is chosen from among H, the alkyl from C1 to C22, each compound of general formula (I) being used as such or in a mixture, as an active principle in a pharmaceutical or cosmetic composition to improve the human epidermal cell repair activity by means of the production of keratin mediated by the cytokeratins cK-19.