How Retatrutide works
Retatrutide keeps the dual-incretin backbone and adds glucagon receptor agonism. That third target raises energy expenditure and drives hepatic lipolysis, so fat loss is pushed from the output side as well as the intake side — appetite down, burn up, liver fat mobilised.
Reported benefits
- Higher total fat-loss ceiling than dual agonists
- Increased resting energy expenditure
- Marked reduction in hepatic fat
- Appetite control retained from the GLP-1 arm
What the research says
Published trial findings, summarised for education. Figures are group averages from controlled studies and are not a promise of individual results.
Phase 2 obesity trial (48 weeks, n=338)
Mean weight reduction of 24.2% at the 12 mg dose versus 2.1% on placebo — the largest reduction reported for a pharmacologic agent at that stage of development; 100% of the highest-dose completers lost ≥5%.
New England Journal of Medicine, 2023
Phase 2 type 2 diabetes trial (36 weeks)
HbA1c fell by up to ~2.16 percentage points with concurrent weight loss of ~16.9%, indicating glycaemic control is preserved despite glucagon receptor activity.
The Lancet, 2023
Hepatic fat sub-study (MRI-PDFF)
Liver fat content dropped by about 82% from baseline at 24 weeks in participants with elevated hepatic steatosis, with the majority reaching normal liver-fat levels.
Nature Medicine, 2024
TRIUMPH phase 3 programme
Large-scale phase 3 trials in obesity, obesity with type 2 diabetes, knee osteoarthritis and obstructive sleep apnoea are ongoing; retatrutide is not yet an approved medicine anywhere.
Eli Lilly clinical trial registry
Tolerability signal
Dose-dependent gastrointestinal events dominate, with transient heart-rate increases and mild ALT elevations reported at higher doses — the reason escalation in trials is slow and supervised.
Pooled phase 2 safety data
Reported side effects
Effects reported in published trials, case reports or post-market surveillance. Individual response varies; this list is educational and not exhaustive.
- Dose-dependent nausea and vomiting
- Diarrhoea and constipation
- Transient heart-rate increase
- Appetite suppression strong enough to affect intake quality
Serious or rare signals
- Investigational agent — long-term safety not yet established
- Glucagon arm can raise fasting glucose in some participants
Regulatory status & sources
Not FDA approved. Retatrutide is in phase 3 development (TRIUMPH programme) for obesity and related conditions.
Safety note
Retatrutide is presented here for research and educational purposes only. It is not offered for human consumption and nothing on this page is medical advice or a dosing protocol. Read the full safety and disclaimer page.