GLP-1 SM features a sequence largely homologous to native GLP-1, with three critical structural modifications that enhance its metabolic stability. These include the substitution of alanine with alpha-aminoisobutyric acid (Aib) at position 8 to resist dipeptidyl peptidase-4 (DPP-4) degradation, and the attachment of a C18 fatty diacid chain via a hydrophilic spacer at position 26. This acylation facilitates high-affinity binding to albumin, which significantly extends the peptide's biological half-life in experimental models compared to native GLP-1.