A method of using proteins of the SIRT family or of polypeptide or peptide fragments of SIRT proteins as an active ingredient for slimming, alone or in combination with at least one other active agent, in a cosmetic composition or for the preparation of a pharmaceutical and/or dermatological composition. The invention also includes the use of the peptides for treatment of cellulite and/or used to decrease, eliminate or prevent excess fat beneath the skin.
