The anabolic agent stanozolol has been used to increase weight and activity in the elderly, but its long-term effects are largely unknown. A double-blind trial of stanozolol against placebo was continued for 12 months. Measurements of weight, fat, fat-free mass, behviour and activity were made at regular intervala, plus detailed biochemical and hermatological profiles. There were no differences between the two groups in respect of weight, fat, fat-free mass and activity levels. There were significant increase in hemoglobin at six and 12 months and packed cell volume at 12 months in the active group. No androgenic side-effects were encountered.