PROBLEM TO BE SOLVED: To provide a circadian rhythm improver which has high safety to a living body and is inexpensive.SOLUTION: A circadian rhythm improver has casein hydrolysate having physical and chemical properties of (a) to (c) below as an active ingredient: (a) ratio of fractions having molecular weight of 1000u or less is 80 mass% or more (b) ratio of fractions having molecular weight of 3500u or more is less than 1 mass% and (c) percentage of a total mass of free amino acid occupied in a total mass of total amino acid contained in casein hydrolysate is less than 10 mass%.COPYRIGHT: (C)2016,JPO&INPIT【課題】生体への安全性が高く、かつ安価な概日リズム改善剤を提供すること。【解決手段】次の(a)乃至(c)の理化学的性質を有するカゼイン加水分解物を有効成分とする概日リズム改善剤:(a)分子量1000ダルトン以下の画分の比率が80質量%以上、(b)分子量3500ダルトン以上の画分の比率が1質量%未満、(c)カゼイン加水分解物に含まれる全アミノ酸の質量合計に占める遊離アミノ酸の質量合計の割合が10質量%未満。【選択図】なし
