Guide

Tirzepatide vs Retatrutide: dual agonist or triple?

Both are 39 residues with a C20 fatty chain. Retatrutide adds the glucagon receptor and drops 82 daltons. What separates them on paper and on a lab report.

Published September 4, 2026

Tirzepatide binds two receptors, GIP and GLP-1. Retatrutide binds those two and the glucagon receptor, which makes it a triple agonist. Both are 39 amino acids long with a C20 fatty diacid attached. Retatrutide is 82 daltons lighter.

Two receptors or three

Tirzepatide was engineered from the GIP sequence to act at both the GIP receptor and the GLP-1 receptor. Retatrutide was engineered from the same starting point to add a third target, the glucagon receptor. In research models that third receptor changes what the molecule does with energy balance, which is the reason it exists.

Neither is a native hormone. Both are designed peptides, and the design is in the substitutions along the chain. The semaglutide comparison covers the single-receptor case.

Same length, same fatty chain

Both are 39 residues. Both carry a C20 fatty diacid through a linker on a lysine. The chain binds albumin in research models and is what stretches the half-life from minutes to days. The two peptides handle the same way: slow to dissolve, keep the water on the glass, swirl and wait.

82 daltons apart

	Tirzepatide	Retatrutide
Residues	39	39
Receptors	GIP, GLP-1	GIP, GLP-1, glucagon
Fatty chain	C20 diacid	C20 diacid
Formula	C225H348N48O68	C221H342N46O68
Molecular weight	4813.45 g/mol	4731.32 g/mol
CAS	2023788-19-2	2381089-83-2

The identity check on a report compares the observed mass to the expected one within a tenth of a percent. For these two that tolerance is about 5 daltons. An 82 dalton gap is sixteen times wider, so a vial of one cannot pass as the other. The expected mass is printed on each product's Specifications tab and on the lab report guide.

Vial sizes and concentration

Tirzepatide comes in 5, 10, 15, 30, 40 and 60 mg vials. Retatrutide in 5, 10, 20, 30, 40 and 50 mg. At 10 mg in 2 mL both are 5 mg/mL; in molar terms tirzepatide is 1.04 mM and retatrutide 1.06 mM, because the lighter molecule packs slightly more moles into the same mass. The calculator has both: tirzepatide and retatrutide.

Peptide	Vial sizes	From
Tirzepatide	5mg, 10mg, 15mg, 30mg, 40mg, 60mg	$42.99 CAD
Retatrutide	5mg, 10mg, 20mg, 30mg, 40mg, 50mg	$53.99 CAD

Free shipping across Canada. Every vial ships with a QR code linking to its own batch lab report. See all peptides

Dual or triple

Tirzepatide is the dual GIP and GLP-1 agonist. Retatrutide adds glucagon. Same length, same fatty chain, 82 daltons apart. Choose by the receptor set your model needs and let the mass on the report confirm the vial.

For research use only. Not for human or animal consumption.

Frequently asked questions

What is the difference between tirzepatide and retatrutide?+

Tirzepatide acts at the GIP and GLP-1 receptors. Retatrutide acts at those two and the glucagon receptor as well. Both are 39-residue acylated peptides; retatrutide is about 82 daltons lighter at 4731.32 g/mol against 4813.45.

Can a lab report tell tirzepatide and retatrutide apart?+

Yes. The expected masses differ by about 82 daltons, roughly 1.7% of the molecule. That is well outside the tenth-of-a-percent tolerance an identity check uses.

Do both carry a fatty acid?+

Yes. Both are lipidated with a C20 fatty diacid on a lysine side chain, which is what gives each its long research half-life.

Which vial sizes do you carry?+

Tirzepatide in 5, 10, 15, 30, 40 and 60 mg. Retatrutide in 5, 10, 20, 30, 40 and 50 mg. Both ship as lyophilized powder.

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