GLP-1 Medicine
Retatrutide: How It Works, Trial Results, and Status
Medically reviewed by HealthRX.com Medical Team · Last reviewed
What is retatrutide?
Retatrutide is an experimental drug being developed by Eli Lilly for obesity and type 2 diabetes. It is sometimes called a triple agonist because it acts on three hormone receptors at once. It is still being tested and is not yet approved or sold.
How does retatrutide work?
Retatrutide activates the GLP-1, GIP, and glucagon receptors. The GLP-1 and GIP actions reduce appetite and improve blood sugar, while the glucagon action may increase the body's energy expenditure, which researchers think contributes to its strong weight-loss effect. [1]
What do the trials show?
In a phase 2 trial published in 2023, retatrutide produced about 24% average body-weight loss at 48 weeks at the highest dose, among the largest reductions seen in obesity drug trials. Phase 3 trials are ongoing, so these results still need to be confirmed in larger studies. [1]
Is retatrutide available or FDA approved?
No. Retatrutide is investigational and is only available through clinical trials. It is not legally sold by prescription. Products marketed as retatrutide outside of trials are not approved, are not quality-controlled, and can be unsafe.
Is retatrutide safe?
In trials, the most common side effects were gastrointestinal, including nausea, vomiting, and diarrhea, similar to other GLP-1 drugs. Because it is still investigational, its long-term safety is not yet established.
How does Retatrutide compare with other peptides?
| Retatrutide | Semaglutide | Tirzepatide | |
|---|---|---|---|
| Receptors targeted | GLP-1, GIP, glucagon | GLP-1 | GLP-1, GIP |
| FDA approved | No (investigational) | Yes | Yes |
| Trial weight loss | ~24% (phase 2) | ~15% (STEP-1) | ~21% (SURMOUNT-1) |
Frequently asked questions
Is retatrutide FDA approved?
No. Retatrutide is investigational and is only available through clinical trials. It is not legally sold by prescription.
How much weight loss does retatrutide cause?
In a phase 2 trial, the highest dose produced about 24% average body-weight loss at 48 weeks, though phase 3 trials are still ongoing.
How is retatrutide different from Ozempic or Mounjaro?
Retatrutide acts on three receptors (GLP-1, GIP, and glucagon), while semaglutide acts on one and tirzepatide on two. The added glucagon action may boost energy expenditure.
Where can I get retatrutide?
It is not available by prescription. Any product sold as retatrutide outside of a clinical trial is unapproved and potentially unsafe.
Citations
This guide is educational and is not a substitute for individualized medical advice. Retatrutide is prescription-only and requires evaluation by a licensed provider.