Tirzepatide: A Research Primer

Tirzepatide is a synthetic 39-amino-acid peptide engineered to act as an agonist at two receptors at once, the GIP receptor and the GLP-1 receptor, which is what "dual agonist" means. It carries CAS number 2023788-19-2 and the molecular formula C225H348N48O68.

What tirzepatide is

Tirzepatide is a single-chain synthetic peptide, 39 residues long, built entirely by chemical synthesis rather than pulled from any tissue. Its backbone is based on the GIP sequence, with substitutions that let one molecule bind both the GIP and GLP-1 receptors. The design idea is a chimera: take the GIP scaffold as the frame and borrow chemistry from the GLP-1 family so that a single sequence answers to both receptors instead of one. Two of its positions use 2-aminoisobutyric acid, a non-standard amino acid that does not occur in ordinary proteins, and one lysine carries a C20 fatty-diacid chain attached through a short linker. The C-terminus is amidated.

Those features together, a long peptide, two engineered receptor targets, an unnatural residue, and a lipid tail, make tirzepatide a more elaborate construct than most of the short peptides filed under the same heading. At close to 4,800 daltons it sits at the large end of what gets casually called a peptide, and the fatty-acid chain gives it a split character: one part of the molecule is water-friendly and one part is not.

The chemistry

The identity data is the part that does not vary between suppliers, so it is what to check first.

• CAS number: 2023788-19-2
• Molecular formula: C225H348N48O68
• Molecular weight: approximately 4,813.5 g/mol
• Length: 39 amino acids
• Class: dual GIP/GLP-1 receptor agonist
• Structural features: two 2-aminoisobutyric acid (Aib) substitutions, a C20 fatty-diacid side chain, a C-terminal amide

A name can be transcribed a dozen ways and a formula can be typed wrong. A CAS registry number cannot be argued with. When you cross-check a supplier's identity claim against a certificate, match the CAS number first, then the formula, then the residue count. The lipid side chain is the detail most worth confirming, because it is easy for a listing to quote the bare peptide's mass and quietly skip the fatty-acid moiety, and those two numbers are not the same.

Where it appears in the research literature

Tirzepatide appears in metabolic-science research. That names the field and stops there.

The papers themselves are a search away. The name "tirzepatide" or the CAS number 2023788-19-2 will surface the primary sources, which is where the actual work lives rather than in a secondhand summary on a product site. Chemists usually group it by target, alongside the GLP-1-receptor and GIP-receptor agonists, a family defined by what the molecules bind. The identity data above is what keeps those searches on the right molecule instead of a similarly named analog.

How it is supplied and handled

Tirzepatide is supplied as a lyophilized solid, meaning freeze-dried to a dry cake, because a solid travels far better than a solution and keeps its integrity while it stays sealed and cold. Store it at -20C and keep it out of light.

Freeze-dried vials of a peptide like this usually contain a bulking agent, so there is a visible cake to work with, and a certificate should account for that filler in the stated mass. The variables that matter for handling are the ordinary ones for a peptide of this class: temperature, moisture, light, and an unbroken seal. Because the molecule is lipidated, it is more sensitive to how it is stored than a plain short peptide, which is another reason to keep it cold and dark.

How the lots are tested

Kits third-party tests every lot it stocks at an independent third-party laboratory. Purity is measured by HPLC read at 220 nm, the standard wavelength for the peptide bond, and identity is confirmed by mass spectrometry, which verifies that the molecule matches the label instead of only measuring how clean the sample is. For a lipidated peptide that mass-spec step carries extra weight, since the fatty-acid chain is exactly the kind of structural feature a mislabeled sample would get wrong.

If you have not read a peptide certificate of analysis before, there is a walkthrough on [how to read one](/research/how-to-read-a-peptide-coa) that uses two real reports, plus a broader [checklist for buying research peptides in Canada](/research/buying-research-peptides-canada) covering what else to verify before you order. The product page for this compound is [tirzepatide](/products/tirzepatide). Kits Peptides ships tracked from Vancouver, BC across Canada.

*All products are supplied as laboratory reagents for research use only. Not for human or veterinary use.*