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Spec sheet · Metabolic & GLP

Semaglutide: specs, mechanism and price check

Acylated GLP-1 receptor agonist with an Aib substitution and a fatty-diacid side chain that binds albumin. Semaglutide was engineered for once-weekly dosing: the side chain binds serum albumin, which slows clearance.

Metabolic & GLPCAS 910463-68-231 residuesGLP-1 S (Purgo label)Updated 2026-11-09
Original illustration for Semaglutide research notes: abstract molecular artwork in orange and teal
Original illustration by USA Peptide Vendors; artistic, not a structural model.

Specifications

Amino acid sequence · 31 residues
  1. H1
  2. X2
  3. E3
  4. G4
  5. T5
  6. F6
  7. T7
  8. S8
  9. D9
  10. V10
  11. S11
  12. S12
  13. Y13
  14. L14
  15. E15
  16. G16
  17. Q17
  18. A18
  19. A19
  20. K20
  21. E21
  22. F22
  23. I23
  24. A24
  25. W25
  26. L26
  27. V27
  28. R28
  29. G29
  30. R30
  31. G31

Sequence as listed by KEGG. X is Aib (2-aminoisobutyric acid); the lysine at position 20 here (Lys26 in GLP-1 numbering) carries the albumin-binding side chain.

PropertyValueSource
CAS number910463-68-2KEGG DRUG D10025
Molecular formulaC187H291N45O59KEGG DRUG D10025
Molecular weight4113.58 g/molKEGG DRUG D10025
PubChem CID56843331KEGG DRUG D10025
Length31 residuesKEGG DRUG D10025

Verified 2026-11-09 against KEGG DRUG D10025 and PubChem CID 56843331. Values we couldn't verify are left out.

Price check: #1 vs #2

Purgo Labs vs the runner-up, from each vendor's own site
#1 Purgo Labs#2 Prime Peptides
Listed itemGLP-1 10mgSemaglutide 20mg
List price$49.99$135.00
With code$37.49 (25% off)No code
Proof Score100/10080/100
Testing labs namedILS Laboratories, Freedom Diagnostics +3Janoshik Analytical, Freedom Diagnostics +2
LinkGet 25% off by using code usapeptidevendorsPrime Peptides ↗

Receptor pharmacology

Evidence level: Clinical: medicinal-chemistry paper and phase 3 trial. All mechanism maps

Semaglutide mechanism diagramGLP-1 receptor agonism with albumin binding that stretches the half-life to about a week. Targets: GLP-1R. Signaling measured: cAMP ↑. Effects reported: Albumin binding, Weight reduction.Semaglutide mechanism mapGLP-1 receptor agonism with albumin binding that stretches the half-life to abouta weekSemaglutideacylated GLP-1 analogueGLP-1RGLP-1 receptor [1]cAMP ↑receptor potency assay [1]Albumin bindinglong half-life [1]Weight reductionSTEP 1 trial [2]Evidence: Clinical: medicinal-chemistry paper and phase 3 trial. Numbers in brackets referto the cited sources.usapeptidevendors.com · Research Use OnlyRECEPTORSIGNALING MEASUREDEFFECTS REPORTED
Trial results apply to the pharmaceutical product, not to research-catalog vials. Open SVG
  1. Lau J et al. Discovery of the Once-Weekly Glucagon-Like Peptide-1 (GLP-1) Analogue Semaglutide. J Med Chem. 2015;58:7370-80.
  2. Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021;384:989-1002.

Research background

Semaglutide was engineered for once-weekly dosing: the side chain binds serum albumin, which slows clearance. Its weight-loss data come from the STEP trials of the pharmaceutical product, not research vials.

3 of 112 directory vendors list Semaglutide; 2 name their testing lab.

COA checklist

  1. Purgo sells it as “GLP-1”. Make sure the COA names the analyte, not just the store label.
  2. Match the CAS number on the certificate to 910463-68-2.
  3. A 31-residue peptide should show a mass-spec identity near 4113.58 g/mol; HPLC purity alone doesn't confirm identity.
  4. 3 of the 112 vendors in our directory list Semaglutide; 2 of those name the lab that tests it.
  5. Purgo lists this as “GLP-1 S” and gives semaglutide's CAS number (910463-68-2) in its product data, but does not use the name semaglutide. Confirm the analyte on the COA.

Semaglutide questions

What is Semaglutide?

Acylated GLP-1 receptor agonist with an Aib substitution and a fatty-diacid side chain that binds albumin. Semaglutide was engineered for once-weekly dosing: the side chain binds serum albumin, which slows clearance. Its weight-loss data come from the STEP trials of the pharmaceutical product, not research vials.

What are Semaglutide's CAS number and molecular weight?

CAS 910463-68-2, formula C187H291N45O59, 4113.58 g/mol, per KEGG DRUG D10025 and PubChem CID 56843331.

Where can US labs buy Semaglutide?

Purgo Labs stocks it as “GLP-1”; code usapeptidevendors takes 25% off at checkout. This page also lists the best-documented second vendor from our 112-vendor directory.

Is research-grade Semaglutide for human use?

No. Vendor material is sold for Research Use Only, not for human or veterinary use.