To further test the effect of Zj7 in improving metabolic homeostasis in a genetically induced obese mouse model, we investigated whether Zj7 can reverse or block the progression of obesity in db/db mice, which carry elevated levels of leptin but are leptin-resistant due to a mutation in the gene encoding the leptin receptor. This evidence concerns the gene LEPR and obesity due to melanocortin 4 receptor deficiency.