A method of increasing muscle mass and strength in mammals by orally administering a therapeutically effective amount of phosphatidic acid. The phosphatidic acid is preferably administered as a plurality of doses per day with at least one dose being administered during the anabolic window following exercise. Preferably, the method further includes the cotemporaneous administration of a therapeutically effective amount of creatine, optionally as phosphatidylcreatine. In addition or in the alternative, the method further includes the cotemporaneous administration of a therapeutically effective amount of leucine, optionally as phosphatidylleucine.