Cobalt PeptidesResearch Grade

Scientific Reference

Semaglutide

Evidence profile: Human Phase 3 evidence

Semaglutide is a synthetic 31-residue analogue of human glucagon-like peptide-1 (GLP-1) that carries a fatty-acid side chain. Three changes separate it from the native hormone (numbering follows native GLP-1): aminoisobutyric acid (Aib) at position 8, arginine in place of lysine at position 34, and an 18-carbon fatty diacid joined through a short linker to the remaining lysine at position 26. Native GLP-1 is cleared from plasma within minutes, and these changes extend the analogue's circulating half-life far beyond that. Alongside receptor pharmacology and rodent work, it has a large human clinical literature in metabolic disease. Less settled is how a peptide of this size, mostly bound to albumin in plasma, reaches receptor-expressing areas of the brain, which rodent studies are still mapping.

Mechanism of Action

Semaglutide has been reported to bind and activate the GLP-1 receptor, a class B G-protein-coupled receptor that signals mainly through Gs and cyclic AMP. In pancreatic beta cells this pathway has been linked to insulin release that depends on the ambient glucose concentration; studies also describe reduced glucagon secretion from alpha cells and slower gastric emptying. GLP-1 receptors are expressed in the hypothalamus and hindbrain, and rodent work has examined these sites in the central control of food intake. The fatty diacid binds albumin reversibly, slowing renal clearance, while the Aib residue resists cleavage by dipeptidyl peptidase-4 (DPP-4).

Molecular Information

  • Type: GLP-1 receptor agonist
  • Length: 31 amino acids
  • Molecular weight: 4114 g/mol
  • Molecular formula: C187H291N45O59
  • CAS: 910463-68-2

Pharmacokinetics

Compared to native GLP-1, semaglutide has a prolonged half-life of around 1 week making it suitable for once weekly subcutaneous administration." and, under Elimination: "With an elimination half-life of approximately 1 week, semaglutide… Maximum concentration was reached 1 to 3 days post dose. Steady state exposure was achieved following 4-5 weeks of once weekly administration. ... Absolute bioavailability of subcutaneous semaglutide was 89%.

Published Research

  • SELECT

    Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes

    Lincoff AM et al. · The New England journal of medicine · 2023 · Clinical

    PMID 37952131 — View on PubMed

  • STEP 1

    Once-Weekly Semaglutide in Adults with Overweight or Obesity

    Wilding JPH et al. · The New England journal of medicine · 2021 · Clinical

    PMID 33567185 — View on PubMed

  • Oral Semaglutide and Cardiovascular Outcomes in People With Type 2 Diabetes, According to SGLT2i Use: Prespecified Analyses of the SOUL Randomized Trial

    Marx N et al. · Circulation · 2025 · Clinical

    PMID 40156843 — View on PubMed

  • Semaglutide once a week in adults with overweight or obesity, with or without type 2 diabetes in an east Asian population (STEP 6): a randomised, double-blind, double-dummy, placebo-controlled, phase 3a trial

    Kadowaki T et al. · The lancet. Diabetes & endocrinology · 2022 · Clinical

    PMID 35131037 — View on PubMed

  • Semaglutide 2·4 mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP 2): a randomised, double-blind, double-dummy, placebo-controlled, phase 3 trial

    Davies M et al. · Lancet (London, England) · 2021 · Clinical

    PMID 33667417 — View on PubMed

  • Oral Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes

    Husain M et al. · The New England journal of medicine · 2019 · Clinical

    PMID 31185157 — View on PubMed