Retatrutide
Retatrutide (Triple GIP/GLP-1/Glucagon Agonist)
The triple agonist showing 24% weight loss in trials
Retatrutide is a next-generation triple hormone receptor agonist (GIP, GLP-1, and glucagon) in Phase 3 clinical trials. Early data showed up to 24.2% body weight reduction - the most ever seen in a drug trial.
Admin routes
Subcutaneous
Popularity
Medium
Side effects
Generally mild
AU vendors
1 rated
✓Key benefits
📈What to expect
Significant appetite reduction; GI adjustment period
Rapid weight loss phase; 6–10% body weight
Continued weight loss; up to 17% in trial data
Up to 24% total body weight loss (Phase 2 data)
Based on community reports and published research. Individual results vary significantly.
💊Dosing protocols
Phase 2 trial protocol
Start 1 mg, titrate to 8–12 mg
Once weekly (subcutaneous)
48 weeks in trials
Dosing information is sourced from published research and community protocols. This is not a recommendation. Consult a healthcare professional.
Research status|Phase 3 clinical trials - Phase 2 data published (NEJM 2023)
Overview
Retatrutide is Eli Lilly's investigational triple agonist that simultaneously activates GIP, GLP-1, and glucagon receptors. While semaglutide targets GLP-1 alone and tirzepatide targets GIP+GLP-1, retatrutide adds glucagon receptor activation. Glucagon promotes hepatic fat oxidation, increases energy expenditure, and enhances thermogenesis. Phase 2 data (published in NEJM, 2023) showed average weight loss of 24.2% at the highest dose over 48 weeks - surpassing both semaglutide and tirzepatide. Phase 3 trials are currently underway with results expected in 2025–2026.
⚙️How it works
Retatrutide combines three mechanisms: GLP-1 receptor activation (appetite suppression, insulin secretion), GIP receptor activation (fat metabolism, insulin sensitivity), and glucagon receptor activation (hepatic fat oxidation, energy expenditure, thermogenesis). The glucagon component is what distinguishes it from tirzepatide. Glucagon increases metabolic rate and promotes the liver to burn fat for energy. The challenge is balancing glucagon's hyperglycaemic effect with the glucose-lowering effects of GLP-1 and GIP - retatrutide's molecular design achieves this balance.
⚡Side effects
📅Research history
Phase 2 trial results show up to 24% weight loss - highest of any GLP-1 class drug
Triple agonist mechanism (GLP-1/GIP/glucagon) generates significant interest
Phase 3 trials underway by Eli Lilly
Research peptide versions become available through compounders
🏪Rated vendors (Australia)
View all →The Peptide Co
Australia (multiple depots) · 99%+ (in-house QC) purity · Same-day dispatch, 1–3 days delivery
thepeptideco.com ↗Vendor ratings are based on community feedback and are not endorsements. Always verify third-party certificates of analysis (CoA) and check current Australian regulations before purchasing.
The weight loss progression
The evolution of pharmaceutical weight loss has been dramatic: semaglutide achieved ~17% (2021), tirzepatide reached ~21% (2022), and retatrutide showed 24.2% (2023). Each generation adds receptor targets for compounding metabolic effects. If Phase 3 data confirms Phase 2 results, retatrutide would become the most effective weight loss medication ever approved. The glucagon component is particularly interesting because it increases energy expenditure - addressing one of the limitations of GLP-1-only agonists where metabolic rate can decline with weight loss.
References
- [1]Rosenstock J, et al. "Retatrutide, a GIP, GLP-1, and glucagon receptor agonist, for people with type 2 diabetes." The Lancet, 2023.
- [2]Jastreboff AM, et al. "Triple hormone receptor agonist retatrutide for obesity." New England Journal of Medicine, 2023.
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Open CalculatorDisclaimer: This guide is for educational and informational purposes only. It is not medical advice. The dosing protocols listed are sourced from published research and community reports and do not constitute a recommendation. Always consult a qualified healthcare professional before using any peptide. Australian regulations classify many peptides as Schedule 4 (prescription-only) substances. Check current TGA guidelines before purchasing.