A next-generation triple receptor agonist showing unprecedented results in obesity and metabolic research — more powerful than any GLP-1 compound to date.
Retatrutide (LY3437943) is an investigational peptide developed by Eli Lilly that simultaneously activates three key metabolic receptors — making it the first triple agonist of its kind.
Key facts about Retatrutide
Unlike semaglutide (Ozempic/Wegovy), which targets only GLP-1 receptors, or tirzepatide (Mounjaro), which targets GLP-1 and GIP, retatrutide adds a third mechanism — glucagon receptor agonism. This triple action produces a significantly more powerful metabolic effect, with Phase 2 clinical trials demonstrating weight loss results that surpass all previously studied obesity medications.
Retatrutide's power comes from simultaneously activating three distinct metabolic pathways, each contributing a different aspect of its effect on weight and metabolism.
GLP-1 receptor agonism reduces appetite and food intake by signalling satiety to the brain. It also stimulates insulin secretion in a glucose-dependent manner, helping to stabilise blood sugar levels after meals.
GIP receptor activation complements GLP-1 by improving insulin sensitivity and reducing fat accumulation in adipose tissue. It also appears to reduce the GI side effects associated with GLP-1 agonism alone, improving tolerability.
This is the key differentiator. Glucagon receptor agonism boosts energy expenditure (the body burns more calories at rest), increases fat breakdown (lipolysis), and significantly reduces liver fat — making it particularly promising for metabolic dysfunction-associated fatty liver disease (MAFLD).
Phase 2 clinical trial data has highlighted several significant areas of benefit beyond weight loss alone.
Phase 2 trials showed mean weight reductions of up to 24.2% over 48 weeks — the highest recorded in any obesity drug trial to date.
Significant reductions in HbA1c in participants with type 2 diabetes, with potential as a diabetes treatment in its own right.
Improvements in blood pressure, triglycerides, and cholesterol observed across trial cohorts, suggesting broad cardiometabolic benefit.
Pronounced reductions in liver fat content, making retatrutide a candidate for treating metabolic fatty liver disease (MAFLD/MASLD).
The glucagon component increases resting metabolic rate, meaning the body burns more calories even without increased physical activity.
Early data suggests a favourable ratio of fat to lean mass loss compared to earlier GLP-1 agents — preserving more muscle during weight loss.
All products are lyophilised powder, lab-tested, and supplied with bacteriostatic water kits.
How does retatrutide compare to the current generation of weight-loss medications?
| Feature | Retatrutide | Tirzepatide | Semaglutide |
|---|---|---|---|
| Receptors targeted | GLP-1, GIP, GCG | GLP-1, GIP | GLP-1 only |
| Avg. weight loss | ~24% | ~22% | ~15% |
| Approval status | Phase 3 trials | FDA Approved | FDA Approved |
| Dosing frequency | Once weekly | Once weekly | Once weekly |
| Liver fat reduction | ✓ Strong | ◑ Moderate | ◑ Moderate |
| Energy expenditure boost | ✓ Yes (glucagon) | ✗ Minimal | ✗ Minimal |
| GI tolerability | ◑ Moderate | ◑ Moderate | ◑ Moderate |
Retatrutide has been evaluated in multiple clinical studies, with Phase 3 trials currently underway.
The landmark Phase 2 trial published in the New England Journal of Medicine enrolled 338 participants with obesity. Over 48 weeks, participants receiving the highest dose (12 mg) achieved a mean weight reduction of 24.2%, with 26% of participants losing more than 30% of body weight. No previous obesity drug had achieved results of this magnitude.
A parallel Phase 2 trial in participants with type 2 diabetes demonstrated significant reductions in HbA1c alongside weight loss. Retatrutide outperformed comparator arms across all glycaemic endpoints, supporting its potential as a dual obesity/diabetes therapy.
Eli Lilly's TRIUMPH programme encompasses multiple large-scale Phase 3 trials evaluating retatrutide across obesity, type 2 diabetes, and cardiovascular outcomes. Results from these trials, expected over the coming years, will determine the path to regulatory approval.
Separate research has evaluated retatrutide's pronounced effect on liver fat reduction, with the glucagon receptor component driving significant hepatic lipid clearance. This positions it as a candidate for metabolic fatty liver disease treatment alongside obesity.
As with all GLP-1 class compounds, retatrutide has a known side effect profile. Most are mild to moderate and dose-dependent.
Research-grade retatrutide, dispatched within 24 hours. Includes full reconstitution guide and next-day delivery across the UK.
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