Both native FGF21 and PsTag fusion of FGF21 reduced blood glucose, insulin, non‐esterified fatty acid (NEFA), leptin, lipid levels and improves glucose tolerance in DIO mice. (A) Fed glucose. (B) Fasting glucose. (C) For OGTT, blood glucose was measured at 0, 15, 30, 60, 90 and 120 min. (D) The glucose AUC during an OGTT from 0 to 120 min. (E) Insulin. (F) Serum cholesterol. (G) Serum triglyceride. (H) NEFA. (I) Leptin. Data are means ± SD; n = 12 per group. * P < 0.05 versus vehicle‐treated HFD mice..