The invention relates to the cosmetic use of isoleucine N-hexadecanoyl of formula (I): CH3—(CH2)14—C(═O)—NH—CH(COOH)—CH(CH3)—CH2—CH3 (I) as a “volumizing” agent and/or as a “plumping” agent for human skin. The invention also relates to a cosmetic treatment method for obtaining a “volumizing” and/or “plumping” effect of the skin of a part of the human body selected from among the breasts, face, cheeks, buttocks and eyelids.