FGF21 and obesity due to melanocortin 4 receptor deficiency: Indeed, first‐generation FGF21 analogues have already reached the clinical stage, and reports from two phase I clinical trials have shown significant improvement of dyslipidemia, slight body weight loss, and reductions in fasting insulinemia in patients with obesity and T2D (Gaich et al, 2013; Talukdar et al, 2016).