Good question, Toni! Here's the actual mechanistic difference 🧬 Tirzepatide is FDA-approved and works as a dual agonist — it activates GLP-1 + GIP receptors, improving insulin sensitivity and appetite control. Retatrutide is still investigational (Phase 3 trials, not yet FDA-approved) and is a triple agonist — it adds glucagon receptor activation on top of GLP-1 + GIP. That extra pathway is linked to increased energy expenditure and fat oxidation. In separate trials, tirzepatide has shown ~15-22% average body weight loss vs. retatrutide's ~24-28% in some trials — though these aren't head-to-head comparisons. Side effects are similar (mostly GI), but retatrutide's long-term safety data is still developing since it's not commercially approved yet. Short version: tirzepatide = approved, two pathways, proven track record. Retatrutide = promising, unapproved, three pathways, still being studied.