Retatrutide: Science & Profile
Last updated July 2, 2026 · Medically reviewed by David Chen, MD, PhD
Retatrutide is a triple agonist: one molecule that activates GLP-1, GIP, and glucagon receptors together. The glucagon arm adds something the others lack — it raises energy expenditure and fat oxidation, so the body burns more on top of eating less. That extra mechanism is why retatrutide has produced the largest weight loss yet seen in this class.
Retatrutide Science
GLP-1, GIP, and glucagon are hormones your body already makes to regulate hunger, insulin, and how aggressively you burn stored energy. Retatrutide is a single molecule that mimics these 3 hormones at once, so their effects stack.
What the trials show
In TRIUMPH 1 (2026), participants lost about 28.3% of body weight at 12 mg over 80 weeks, reaching up to 30.3% in higher-BMI participants by 104 weeks. The TRANSCEND-T2D-1 trial showed a 2.0% HbA1c drop alongside 16.8% weight loss in type 2 diabetes, and a knee-osteoarthritis arm (TRIUMPH 4) reported large pain reductions.
How it is dosed
Retatrutide is given once weekly, started low and stepped up every four weeks until maintenance. Model the schedule and projected loss in the dosing calculator, and note its half-life in the half-life explainer.
Status and side effects
Retatrutide is investigational — not yet FDA-approved and awaiting filing. Alongside the usual gastrointestinal effects, it has a distinctive dose-dependent skin-tingling (dysesthesia) effect at higher doses. See the full side-effect breakdown or compare it against semaglutide and tirzepatide.
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