The invention relates to peptides of general formula (I): €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒR 1 -AA-R 2 €ƒ€ƒ€ƒ€ƒ€ƒ(I) which can regulate neuronal exocytosis, their stereoisomers and racemic or non-racemic mixtures thereof, and the cosmetically or pharmaceutically acceptable salts thereof, wherein AA is a sequence of 3 to 40 adjacent amino acids contained in the amino acid sequence of the SNAP-25 protein, R 1 is selected from the group consisting of H or alkyl, aryl, aralkyl or acyl group and R 2 is selected from the group consisting of amino, hydroxyl or thiol, substituted or non-substituted with aliphatic or cyclic groups, with the condition that when R 1 is H or acetyl, R 2 is not non-substituted amino, hydroxyl or thiol. The invention also relates to a method of obtaining such peptides, cosmetic or pharmaceutical compositions containing them and their use to treat those conditions requiring neuronal exocytosis regulation, preferably for treating the skin.