- Same-day UK dispatch on orders before 3pm
- Certificate status shown on every product
- Shop all research peptides
- Learn: guides and research tools
Tirzepatide
In stock10 mg20 mg40 mg
From£60.00
Research area
Incretin & Amylin Analogues
For research use only. Not for human or veterinary use. Sold strictly for in-vitro laboratory research; not for diagnosis or treatment.
The compounds in this research area are synthetic peptide analogues of the incretin hormones and of amylin, built on chains of roughly thirty to forty amino acid residues. What they share is a modified natural backbone. Several carry the non-proteinogenic residue α-aminoisobutyric acid (Aib) at selected positions, and each is lipidated: a long-chain dicarboxylic acid is attached to the peptide through a linker. By receptor class, semaglutide is a GLP-1 receptor agonist peptide, tirzepatide a GIP and GLP-1 receptor agonist peptide, GLP-3 (retatrutide) a GIP, GLP-1 and glucagon receptor agonist peptide, and cagrilintide a lipidated amylin analogue. Where catalogued, molecular weights run from 4113.58 g/mol for semaglutide (C187H291N45O59) to 4813.45 g/mol for tirzepatide (C225H348N48O68). Each compound is supplied as a lyophilised solid in a sealed vial.
Compounds in this research area
GLP-3
In stock10 mg20 mg30 mg40 mg
From£59.00Cagrilintide
In stock10 mg
£75.00Semaglutide
In stock15 mg20 mg
From£48.00
Structural features
Every compound in this research area is a peptide chain with a lipid group covalently attached, and the way that group is fixed to the chain is the clearest structural signature of the class. In semaglutide, a chain of thirty-one amino acid residues, the side chain of the lysine at position 20 carries an octadecanedioic (C18) diacid, joined through a γ-glutamic acid residue and two short ethylene-glycol-based spacer units. Tirzepatide is a linear chain of thirty-nine residues conjugated to a C20 dicarboxylic acid, and its sequence is based on that of GIP. Cagrilintide, a lipidated amylin analogue, is acylated at its N-terminus instead: a C20 diacid is attached through a γ-glutamic acid residue to a chain of thirty-seven residues.
Two further features recur. Semaglutide carries α-aminoisobutyric acid (Aib) at position 2, a non-proteinogenic residue with two methyl groups on its α-carbon; because that carbon bears no hydrogen, Aib has no stereocentre. Cagrilintide contains a disulfide bridge between its two cysteine residues, which closes a short ring near the N-terminus, and it ends in a C-terminal prolinamide. GLP-3 (retatrutide) is catalogued with the formula C221H342N46O68 and a molecular mass of 4731.4 g/mol; like the others, it is a synthetic lipidated peptide.
The attached diacid gives each molecule an amphiphilic character: a long hydrocarbon chain on an otherwise polar peptide. Where a molecular mass is catalogued, it lies between roughly 4.1 and 4.8 kDa, which places these compounds between short synthetic peptides and small proteins. Each molecular formula covers the peptide chain and the lipid group together, so the identifiers describe the whole conjugate rather than the chain alone.
Identifiers at a glance
| Compound | CAS number | Molecular formula | Molecular weight |
|---|---|---|---|
| Tirzepatide | 2023788-19-2 | C225H348N48O68 | 4813.45 g/mol |
| GLP-3 | 2381089-83-2 | C221H342N46O68 | 4731.4 g/mol |
| Cagrilintide | 1415456-99-3 | C194H312N54O59S2 | 4409.01 g/mol |
| Semaglutide | 910463-68-2 | C187H291N45O59 | 4113.58 g/mol |
Analytical considerations
Lipidated peptides of this length are demanding analytes. In reversed-phase HPLC the hydrocarbon chain lengthens retention considerably, so methods for this class typically run steeper organic gradients than those used for short unmodified peptides, often on C8 or C18 columns with an acidified water and acetonitrile mobile phase. Related substances of interest include deletion and truncation sequences from synthesis, forms lacking or carrying an altered lipid side chain, and oxidised or deamidated variants, several of which elute close to the main peak.
Identity is confirmed by mass spectrometry. At masses above 4 kDa, electrospray ionisation gives a series of multiply charged ions, and the spectrum is deconvoluted to a neutral mass that is compared with the average mass calculated from the molecular formula. For molecules of this mass the monoisotopic peak is weak, so the average mass is the more practical comparison. A certificate of analysis for a compound in this class would be expected to show a reversed-phase chromatogram with the area of the main peak, a measured mass against the expected value and a batch number; those figures describe the batch tested, not the class as a whole.