GLP-3 (RT)

Retatrutide extends the multi-agonist strategy to three receptors, adding glucagon receptor activity to the GIP and GLP-1 engagement seen in tirzepatide. The rationale in the literature is that glucagon receptor agonism contributes energy expenditure effects that incretin agonism alone does not, while the incretin arms offset the glycaemic consequences of glucagon signalling. Whether that balance holds across models is exactly what current work is probing.

This is comparatively new chemistry and the synthesis is unforgiving — deletion sequences and incompletely deprotected side chains are the usual failure modes. We hold retatrutide lots in quarantine for a second independent assay run before release rather than shipping on a single certificate, which is why lead times in this category occasionally run longer than the rest of the catalogue.