The invention concerns a methionine-derived peptidomimetic represented by the following general formula (II):R═X—C(O)—NH— with X=alkyl or alkyloxy (C1-C4); R′═HThe invention also concerns a composition for preventing or fighting cutaneous disorders associated to a mitochondrial dysfunction, and the use of a methionine-derived peptidomimetic as a cosmetic agent for protecting and/or stimulating the mitochondria of cutaneous cells.