To provide a metabolism improver containing a rare fatty acid such as hydroxylated fatty acid, oxo fatty acid, and a food or pharmaceutical containing the metabolism improver.SOLUTION: A metabolism improver contains (1) a C18 fatty acid having a hydroxy group or carbonyl group at position 13, (2) a C20 fatty acid having a hydroxy group or carbonyl group at position 15, (3) a C20 fatty acid having a hydroxy group or carbonyl group at position 12, or (4) a C16 fatty acid having a hydroxy group or carbonyl group at position 10.SELECTED DRAWING: None【課題】水酸化脂肪酸、オキソ脂肪酸等の希少脂肪酸を含む代謝改善剤、及び、当該代謝改善剤を含む食品、医薬品の提供。【解決手段】(1)13位に水酸基またはカルボニル基を有する炭素数18の脂肪酸、(2)15位に水酸基またはカルボニル基を有する炭素数20の脂肪酸、(3)12位に水酸基またはカルボニル基を有する炭素数20の脂肪酸、又は(4)10位に水酸基またはカルボニル基を有する炭素数16の脂肪酸を含む、代謝改善剤。【選択図】なし