Administration of 50 mg/kg MSL to ob/ob mice, a genetic mouse model of obesity with a leptin mutation34, 3 times a week for 8 weeks significantly reduced nonfasting and fasting blood levels (Fig. 4a, b) without changes in food intake or body weight (Supplementary Fig. 8a, b). The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.