Peptides of general formula (I): R1-Wn-Xm-AA1-AA2-AA3-AA4-AA5-AA6-Yp-Zs-R2 their stereoisomers, mixtures thereof and/or their cosmetically or pharmaceutically acceptable salts, their preparation process, cosmetic or pharmaceutical compositions which contain them and their use in the treatment and/or care of conditions, disorders and/or diseases that are a consequence of muscle contraction.