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, andR 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.