PROBLEM TO BE SOLVED: To provide a material capable of inhibiting activation of PPARγ (Peroxisome Proliferator Activated Receptor gamma).SOLUTION: This invention relates to: a PPARγ activity inhibitor containing citral or piperine as an active ingredient and a differentiation and/or maturation inhibitor of adipocytes containing citral or piperine as an active ingredient.COPYRIGHT: (C)2014,JPO&INPIT【課題】PPARγの活性化を抑制することができる素材の提供。【解決手段】シトラール又はピペリンを有効成分とするPPARγ活性抑制剤。【選択図】なし