Peptide Library / Weight & Metabolic
Retatrutide
Also known as: LY3437943, "triple G"
The next-generation weight compound — a triple agonist (GLP-1 + GIP + glucagon) that posted the largest weight-loss numbers ever seen in trials. Still in phase 3.
| Typical research dose | 0.5–1 mg/week to start; titrate slowly (trial range up to 12 mg/week) |
|---|---|
| Frequency | 1× weekly |
| Route | Subcutaneous injection |
| Cycle length | Ongoing with medical-style titration; not a short cycle |
Figures reflect protocols commonly reported in the research community — not a prescription or a recommendation.
What it is
Retatrutide is Eli Lilly's triple-receptor agonist: it hits GLP-1 (like semaglutide), GIP (like tirzepatide), and the glucagon receptor, which adds an energy-expenditure effect the others don't have. In its phase-2 trial, the top dose produced ~24% average body-weight loss at 48 weeks — the largest ever recorded for a drug — and it is currently in phase-3 trials, meaning it is not an approved medication anywhere yet.
What the research looks at
- Weight loss — the headline: 17–24% reductions at higher doses in phase 2.
- Blood sugar — strong glycemic improvements in type-2 diabetes cohorts.
- Liver fat — dramatic reductions in liver-fat content in sub-studies.
- What's missing — phase-3 completion and any approval; long-term safety is literally still being established in trials right now.
How protocols are commonly structured
Trial design is the only honest template: start very low (0.5–1 mg once weekly) and titrate up every 2–4 weeks only as tolerated, because the gastrointestinal side effects are dose-dependent and front-loaded. The phase-2 range ran 1–12 mg weekly. The research community treats the titration schedule as the protocol — jumping to a high dose immediately is the classic self-inflicted mistake with this class. The class's standing rule carries over: a personal or family history of medullary thyroid cancer sits this category out.
Reconstitution & storage
Lyophilized powder; bacteriostatic-water reconstitution (calculator). Weekly dosing in mg — vial strengths (10/20/30 mg) map to multi-week supplies depending on where in the titration you are. Refrigerate after mixing.
Research protocols, not a prescription — talk to a physician before touching anything.