The present invention addresses providing an amino acid-containing composition that contains fewer types of amino acids and provides a high anti-fatigue effect and/or a lipid metabolism promoting effect which compares favorably with conventional products. Provided is an anti-fatigue and/or lipid metabolism-promoting amino acid-containing composition which comprises arginine, valine, and serine. Provision of said anti-fatigue and/or lipid metabolism-promoting amino acid-containing composition helps to prevent or reduce fatigue during exercise and to produce a lipid metabolism promoting effect. Application of said anti-fatigue amino acid-containing composition increases the possibility of a person with less physical activities to make exercise a habit, and enables designing of a feed or a food product for sports amateurs, athletes, pets, or racing animals.
