Two of the most-studied incretin research peptides, side by side. A factual look at how Retatrutide and Tirzepatide differ at the receptor level.
Two of the most-requested research peptides we stock are Retatrutide and Tirzepatide. They're often mentioned together because both belong to the incretin receptor–agonist family — but at the molecular level they're distinct. This is a factual, research-only comparison.
The core difference: receptor targets
Tirzepatide is characterised in the literature as a dual agonist, acting on two incretin receptors: GIP and GLP-1. Retatrutide is described as a triple agonist — it adds a third target, the glucagon receptor, to those same two. That extra receptor target is the headline structural difference between them.
Form and handling
In practical lab terms the two are handled the same way. Both are supplied as lyophilised powders, both are reconstituted with bacteriostatic water, and both are stored cool and dark as dry vials and refrigerated once in solution.
Vial sizes
The ranges differ. Tirzepatide is stocked in 30mg and 60mg vials, while Retatrutide is offered across a wider set of strengths from 10mg upward. Choice of vial size in research usually comes down to the scale of the work and the concentrations required.
What they share
Both are third-party tested to ≥99% purity with a Certificate of Analysis available per batch. As with everything we supply, both are strictly for in-vitro laboratory research — not for human or animal use.
If you're mapping out where each sits in the wider catalogue, our guide to research-peptide categories puts both in context alongside the other families we stock.
This article is for general educational purposes only and relates to laboratory research use. It is not medical, veterinary or professional advice. All Negra Peptides products are supplied strictly for in-vitro research — For Research Use Only, Not for Human Consumption.