Provided are a composition and a method for improving the protein use efficiency ratio in a subject living body. More specifically, the present invention provides a composition for improving protein use efficiency ratio, said composition comprising carnitine as an active ingredient, and a method for using the same.本發明係提供一種可提升在對象生物體內之蛋白質的利用效率的組成物及方法。 更詳而言之,本發明係提供一種包含肉鹼作為有效成分而成之用以提升蛋白質利用效率之組成物、及使用其之方法。