The purpose of the present invention is to provide a composition, which comprises as an active ingredient a substance having an effect of preventing a decrease in muscle mass, preventing a decrease in muscular power, increasing muscle mass or enhancing muscular power as well as a high safety and which is to be used for preventing a decrease in muscle mass, preventing a decrease in muscular power, increasing muscle mass or enhancing muscular power, and a method for preventing a decrease in muscle mass, preventing a decrease in muscular power, increasing muscle mass or enhancing muscular power. The composition according to the present invention for preventing a decrease in muscle mass, preventing a decrease in muscular power, increasing muscle mass or enhancing muscular power comprises, as an active ingredient, one or more members of soya sapogenols and/or soya saponins.本發明係以提供一種具有抑制肌肉量減少作用、抑制肌力下降作用、肌肉量增加作用或肌力增加作用，而且包含高安全性物質作為有效成分的抑制肌肉量減少用、抑制肌力下降用、肌肉量增加用或肌力增加用之組成物，及抑制肌肉量減少、抑制肌力下降、增加肌肉量或增加肌力之方法為目的。本發明之抑制肌肉量減少用、抑制肌力下降用、肌肉量增加用或肌力增加用之組成物係包含大豆皂醇類及/或大豆皂苷類的1種以上作為有效成分。
