Retatrutide FDA Approval Status
FDA Approved: No
Generic name: retatrutide
Company: Eli Lilly and Company
Treatment for: Weight Loss (Obesity/Overweight)
Last updated by Melisa Puckey, BPharm on Sep 16, 2025.
Retatrutide is a triple hormone (GIP, GLP-1 and glucagon) receptor agonist in development for the treatment of obesity.
- Retatrutide works as a triple–hormone-receptor agonist (GIP–GLP-1–GCG receptor agonists) by targeting three different hunger-regulating hormones:
-
- GIP (gastric inhibitory peptide or glucose-dependent insulinotropic polypeptide) is an incretin hormone that is released from the gut after eating. It stimulates the beta-cells in the pancreas to secrete insulin.
- GLP-1 (glucagon-like peptide-1) is also an incretin hormone that stimulates the beta-cells to secrete insulin.
- GCG (glucagon) is a hormone secreted from the alpha-cells in the pancreas. It stimulates glucose production in the liver and helps maintain adequate plasma glucose concentrations.
- During early development, its code name was LY3437943, and it has also been nicknamed 'triple G' because it is an agonist of all three "G" receptors. Retatrutide is also known as reta peptide or reta, as it is a peptide-based medicine.
- Phase 2 clinical trial results published in The New England Journal of Medicine show retatrutide achieved up to 17.5% mean weight reduction at 24 weeks in adults with obesity and overweight. In a secondary endpoint, retatrutide demonstrated a mean weight reduction of up to 24.2% at 48 weeks.
- Retatrutide is an injection that is administered once weekly.
- Obesity is a complex disease that occurs when an individual’s weight is higher than what is considered healthy for his/her height. According to the CDC, people with a body mass index (BMI) between 25 and 29.9 are considered overweight, and people with a BMI of 30 or higher are considered obese.
What is the dose of retatrutide?
As it is not an FDA-approved medicine, there is no FDA-approved dose of retatrutide.
In the Retatrutide Phase 2 clinical trial (NCT04881760):
- Weekly doses of retatrutide 1 mg, 4 mg, 8 mg, or 12 mg were compared with placebo
- Trial duration was 48 weeks
Experimental weekly dose treatment regimes included:
- 1mg dose
- Initial dose of 2mg and increasing to 4mg
- 4mg dose
- Initial dose 2mg increasing to 8mg
- Initial dose 4 mg increasing to 8 mg
- Initial dose 2 mg increasing to 12 mg
- Placebo
Disclaimer: dosing outside trials is unsafe and not recommended.
Weight reduction outcomes
The Phase 2 clinical trial demonstrated a dose-dependent reduction in body weight among participants receiving retatrutide.
Retatrutide weight loss results
- Results at 24 weeks: average weight loss for each dose group
- 1 mg group lost 7.2% of their body weight
- 4 mg lost 12.9%
- 8 mg lost 17.3%
- 12 mg lost 17.5%
- The placebo lost only 1.6%
- Results 48 weeks: average weight loss per dose group:
- 1 mg lost 8.7%
- 4 mg lost 17.1%
- 8 mg lost 22.8%
- 12 mg lost 24.2%
- The placebo group saw only a modest 2.1% decrease
Can you get retatrutide yet?
No, retatrutide is only available in clinical trials. It is currently in the development process and is undergoing Phase 3 clinical trials (NCT05882045). As it is not FDA-approved, it is not available in pharmacies or online.
Any products purporting to be retatrutide are not legitimate and are illegal and unsafe. Under federal law, Retatrutide cannot be used in compounded medicines.
FDA-approved obesity medicines include Zepbound (tirzepatide), which is a GIP and GLP-1 receptor agonist, and Wegovy (semaglutide), which is a GLP-1 receptor agonist. There are many other prescription medicines available for this condition.
What are the side effects of retatrutide?
- The most frequently reported side effects were gastrointestinal, including nausea, diarrhea, vomiting, and constipation.
- These side effects occurred more frequently with retatrutide than with placebo and increased in frequency at higher doses.
- The long-term safety profile is unknown until further studies are complete. More details of side effects will be available on the Prescribing Information that will be available if retatrutide becomes an FDA-approved medicine.
How much will retatrutide cost?
The price has not been announced as it is still in development and is not yet an FDA-approved medicine.
Development timeline for retatrutide
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.