Aging is associated with decreases in food intake and GH secretion, termed the ‘anorexia of aging’ and ‘somatopause’, respectively. The mechanisms underlying these phenomena are not fully understood. While many approaches have attempted to improve these age-related physiologic changes, none have achieved satisfactory results. Ghrelin, a 28 amino-acid acylated peptide, was identified as an endogenous ligand for the GH secretagogue receptor (GHS-R). Ghrelin stimulates GH secretion and food intake in animals and humans. Previous studies have demonstrated that the mean plasma concentrations of ghrelin in normal-weight elderly people were lower than those in younger people. We hypothesized that ghrelin administration might improve the metabolic and physiologic changes that accompany the ‘anorexia of aging’ and ‘somatopause’. First, 75 week-old mice fasted for 72 h, after which they resumed feeding with subcutaneous administration of ghrelin (360 mcg/kg) twice daily for four days. Multiple administrations of ghrelin after a 72-h fast increased food intake and hastened body weight recovery with a high lean body mass ratio. Next, 50 week-old mice were subcutaneously injected with rat ghrelin (40 mcg/kg) twice weekly from 50 to 80 weeks of age. Long-term administration of ghrelin kept aged mice with low body weight and low adiposity. These results suggest that ghrelin might be a novel approach for the therapy of age-related metabolic and physiologic changes.