Research / laboratory use only. This page is a technical and sourcing reference for raw-material evaluation. It does not describe human use, dosing, or therapeutic outcomes, and nothing here is medical advice.
Buyer Reference · Research Use Only
GLP-1, GIP & Glucagon Peptides: A B2B Sourcing Reference
“GLP-1” is used loosely across the market, but the leading molecules act on different receptors and carry different regulatory status. Here is a precise, research-use reference for buyers comparing semaglutide, tirzepatide and retatrutide raw material.
The science, briefly
What “GLP-1 class” peptides actually are
These molecules are signaling peptides: they act as agonists at incretin and related receptors that influence glucose handling and appetite signaling. The newer molecules differ mainly in which receptors they activate and how strongly and durably they bind.
A frequent misconception is that they are tiny 4–8 amino-acid peptides. They are not — they are modified peptides of ~31–39 amino acids with a fatty-acid chain. The “generations” differ by sequence, lipid modification and receptor targets, not by length.
Side by side
Single vs dual vs triple agonist
Semaglutide
- Receptor profile
- GLP-1 receptor agonist (single)
- Peptide length
- 31 amino acids
- Status
- Approved (e.g. Ozempic / Wegovy / Rybelsus, Novo Nordisk — Denmark)
The reference single-target GLP-1 analog.
Tirzepatide
- Receptor profile
- GIP / GLP-1 dual agonist
- Peptide length
- 39 amino acids
- Status
- Approved (Mounjaro / Zepbound, Eli Lilly)
A dual incretin — not a pure GLP-1, despite common shorthand.
Retatrutide
- Receptor profile
- GIP / GLP-1 / glucagon triple agonist
- Peptide length
- 39 amino acids
- Status
- Investigational — not yet FDA-approved (Phase 3, Eli Lilly)
A triple agonist; treat its regulatory status as distinct from approved molecules.
Use “GLP-1 class” as a commercial umbrella if you must, but keep specifications, COA and quotations precise about the receptor profile and molecule.
Before you order
What to verify on the documentation
- Real content, not just purity — confirm the actual mg delivered, not only the HPLC purity %. See purity vs content →
- Batch-specific COA — matched to the quoted lot.
- HPLC + MS — purity chromatogram and molecular-weight identity.
- Analytical method — instrument, column, mobile phase, column temperature, so the result is reproducible on the goods you receive.
- Format & status — lyophilized powder; confirm the molecule and its regulatory status for your market.
FAQ
Common buyer questions
Are semaglutide, tirzepatide and retatrutide all GLP-1 peptides?
Only semaglutide is a pure GLP-1 receptor agonist. Tirzepatide is a GIP/GLP-1 dual agonist, and retatrutide is a GIP/GLP-1/glucagon triple agonist. "GLP-1 class" is a useful umbrella term commercially, but technical and scientific documentation should state the precise receptor profile.
How many amino acids do these peptides have?
Semaglutide is a 31-amino-acid GLP-1 analog; tirzepatide and retatrutide are each 39-amino-acid peptides. They are modified peptides with fatty-acid chains, not short 4–8 residue peptides — a common misconception. The generational differences come from sequence modification, the lipid chain and the number of receptors targeted, not from peptide length.
Is retatrutide approved?
No. As of 2026 retatrutide is an investigational molecule in Phase 3 trials and is not FDA-approved. Buyers should treat its legal and regulatory status as different from approved molecules and handle it accordingly.
What should I verify before ordering GLP-1 class raw material?
Request a batch-specific COA, the HPLC chromatogram (purity), MS data (molecular-weight identity), and the real content (actual mg, not just purity %). For serious verification, ask for the analytical method so the result can be reproduced on the material you receive. See our purity-vs-content guide.