Semaglutide is a 31-residue analogue of human GLP-1(7–37). Two backbone substitutions distinguish it from the native hormone: 2-aminoisobutyric acid replaces alanine at position 8, which blocks cleavage by dipeptidyl peptidase-4, and arginine replaces lysine at position 34 so that only a single lysine remains available for derivatisation. The epsilon-amine of that lysine (Lys26) carries a side chain built from two 8-amino-3,6-dioxaoctanoic acid spacers, a gamma-glutamate and a C18 fatty diacid.

That fatty diacid mediates reversible binding to serum albumin, which is the protraction mechanism behind the molecule's extended plasma half-life; the peptide itself is an agonist at the GLP-1 receptor, a class B G-protein-coupled receptor expressed in pancreatic islets, the gastrointestinal tract and the central nervous system. Semaglutide has been through a large randomised clinical programme and is approved and marketed as a prescription medicine under the Ozempic, Rybelsus and Wegovy brands in the United States, the European Union, Canada, Japan and Australia among others.

The honest limitation for a catalogue like this one is that essentially all of the published human evidence was generated with the licensed, formulated, sterile drug product manufactured under GMP. Research-grade lyophilised material is a different article: it is not a medicine, is not formulated or sterile-filled, and its behaviour cannot be assumed to match the licensed product. Identity and content should be read from the certificate of analysis for the specific lot.