The invention relates to the cosmetic use of isoleucine N-hexadecanoyl of formula (I): CH3&mdash(CH2)14&mdashC(&boxHO)&mdashNH&mdashCH(COOH)&mdashCH(CH3)&mdashCH2&mdashCH3 (I) as a &ldquovolumizing&rdquo agent and/or as a &ldquoplumping&rdquo agent for human skin. The invention also relates to a cosmetic treatment method for obtaining a &ldquovolumizing&rdquo and/or &ldquoplumping&rdquo effect of the skin of a part of the human body selected from among the breasts, face, cheeks, buttocks and eyelids.