Retatrutide
Retatrutide is an investigational triple GIP/GLP-1/glucagon receptor agonist from Eli Lilly that is not yet FDA-approved; it remains in the Phase 3 TRIUMPH clinical trial program, with a biologics license application reportedly planned for the first quarter of 2027.
This page is a research-orientation summary, not a dosing guide. For anything beyond general background, read the primary literature or talk to a qualified clinician — specifics like amount, frequency, or administration aren't something we publish here.
What it does & how it works
Retatrutide is a synthetic peptide engineered to simultaneously agonize three distinct receptors: GIP, GLP-1, and the glucagon receptor. Combined GIP/GLP-1 agonism drives glucose-dependent insulin secretion and appetite suppression through central and peripheral incretin pathways, while added glucagon receptor agonism is believed to increase hepatic energy expenditure and lipid oxidation, an effect distinct from GLP-1/GIP-only agonists. Fatty-acid acylation provides albumin binding for an extended half-life supporting infrequent dosing.
Typical results seen in research
In the Phase 2 dose-finding trial, participants with obesity lost up to roughly 24% of body weight at 48 weeks at the highest dose, among the largest reductions reported for an incretin-based therapy to date. Topline Phase 3 TRIUMPH data have reported weight loss in the range of roughly 12.7% to 22.6% depending on dose and population (including participants with type 2 diabetes or cardiovascular disease), alongside improvements in triglycerides, HbA1c, and inflammatory markers such as high-sensitivity CRP; these results are investigational and have not yet been reflected in an FDA-approved label.
How it’s commonly used
In clinical trials, retatrutide has been administered via subcutaneous injection using a prefilled pen or device, similar to other incretin-based peptide therapies. It is not currently available outside of clinical trial enrollment or investigational research settings, and no approved dosing regimen exists.
- New England Journal of Medicine · 2023 Triple-Hormone-Receptor Agonist Retatrutide for Obesity
- Diabetes, Obesity and Metabolism · 2025 Retatrutide for the treatment of obesity, obstructive sleep apnea and knee osteoarthritis: Rationale and design of the TRIUMPH registrational clinical trials
- Diabetes/Metabolism Research and Reviews · 2024 Effects of once-weekly subcutaneous retatrutide on weight and metabolic markers: A systematic review and meta-analysis of randomized controlled trials
Curated from published literature for research orientation. Not an exhaustive review, and not a substitute for reading primary sources.
- Retatrutide Phase 2b Data Show Kidney-Protective Effects in Chronic Kidney Disease —
- Retatrutide's TRIUMPH-2 Trial Shows Major Weight Loss and A1C Improvement in Adults With Type 2 Diabetes —
- Retatrutide's TRIUMPH-3 Trial Shows Over 20% Weight Loss in Adults With Obesity and Heart Disease —