QW contributed to the conception and design of the study; YW contributed to performing the major body of the experiments and data analysis of the study; XB, JH and XZ contributed to supaglutide production and performing of CD-1 and db/db mice related experiments. QC and WL contributed to performing part of experiments. YW, XB, JH, XZ, WL, QC, DJ, ZW, RL, and QW contributed to analysis and interpretation of the data. YW and QW contributed to writing the article. All authors have revised the manuscript critically for important intellectual content and given final approval of the version to be published.