30mg lyophilized vial
Metabolic · Research Peptide
Triple agonist GLP-1 / GIP / glucagon receptor peptide.
01 · Overview
Retatrutide (LY-3437943) is Eli Lilly's next-generation obesity drug candidate — the first single molecule to hit all three incretin/metabolic receptors that matter for body weight. Where semaglutide (Ozempic/Wegovy) is a GLP-1 agonist and tirzepatide (Mounjaro/Zepbound) is a dual GLP-1/GIP agonist, retatrutide adds a glucagon receptor arm on top. The glucagon pathway matters because it directly increases energy expenditure and hepatic fat oxidation — you don't just eat less, you also burn more.
Phase 2 trial results published in the NEJM (2023) showed roughly 24% average body-weight reduction at 48 weeks on the highest dose — the largest weight-loss numbers ever reported for a pharmacological agent. Phase 3 trials are ongoing; FDA approval is expected in the 2026–2027 window.
02 · Fit
People who've plateaued on diet alone, or who struggle with constant food noise and want the strongest metabolic lever currently in trials.
03 · Mechanism
Retatrutide is a synthetic single-molecule triple agonist targeting the GLP-1, GIP, and glucagon receptors, driving glucose regulation, appetite suppression, and increased energy expenditure simultaneously.
04 · Use cases
05 · Protocols
Reference protocols paraphrased from published research and common clinical practice. Individual response varies. Work with a qualified provider before running anything below.
Beginner titration (standard)
Protocol
2mg once weekly for 4 weeks, then step up 2mg every 4 weeks as tolerated
Duration
24–48 weeks minimum for meaningful body composition change
Notes
Clinicians typically cap real-world dosing at 8–12mg weekly. Going higher rarely improves results and worsens GI side effects.
Sensitive / GI-prone user
Protocol
0.5–1mg weekly for the first 4 weeks, then 2mg, then step up slowly
Duration
Same 24–48 week arc, just extended
Notes
Half-doses at the start dramatically reduce nausea and constipation without slowing final results much.
Maintenance after target reached
Protocol
Lowest effective weekly dose that holds weight (often 2–4mg)
Duration
Indefinite in clinical use; some research users cycle off for 8–12 weeks
Notes
Fully discontinuing usually results in significant weight regain — this is a chronic-use class, not a short cycle.
Baseline reconstitution
Reconstitute 30mg vial with 3ml bacteriostatic water for a concentration of 10mg/ml.
06 · Combinations
Most users run retatrutide alone while titrating. Once stable, common additions are creatine + high protein intake to protect lean mass, and glutathione / NAD+ for oxidative and energy support during the deficit. Combining with other GLP-1s (semaglutide, tirzepatide) is not done — they compete on the same receptors.
07 · Safety
08 · Trivia
09 · FAQ
Ozempic (semaglutide) hits one receptor (GLP-1). Mounjaro (tirzepatide) hits two (GLP-1 + GIP). Retatrutide hits three (GLP-1 + GIP + glucagon). The extra glucagon activity increases energy expenditure on top of appetite suppression.
Not yet. It's in Phase 3 trials. Anything you see labeled 'retatrutide' outside a clinical trial is a research-grade peptide, not an approved medicine.
You can, if you eat too little protein or skip resistance training. High protein (1g per pound of goal weight) plus lifting 3x/week is the standard playbook to protect lean mass.
Trial data on similar GLP-1 drugs shows most people regain roughly two-thirds of lost weight within a year of stopping unless they've locked in significant habit change first.
10 · References
Educational disclaimer
Everything on this page is for research and educational purposes only. It is not medical advice, a prescription, or a substitute for a conversation with a qualified clinician who knows your full history. Peptides interact with medications, hormones, and existing conditions in ways that require real oversight.