Arginine, administered orally (arginine aspartate 37.5 g), induces upon voluntary fasting man laying down in bed (muscular rest), an increase of: 1) plasmatic HGH rate (radioimmunological) at 2 hours, 2) plasmatic SMs rate (biological: incorporation of 3H thymidine in human lymphocytes) at 8 hours, when compared with an equal administration of aminoacids without arginine or aspartate as placebo. Arginine enhances endogenous secretion of the complex HGH-somatomedines.