Retatrutide Injection
Everything about its mechanism of action, clinical studies, safety and current approval status
Retatrutide at a Glance
What Is Retatrutide?
Retatrutide is an investigational active ingredient developed by Eli Lilly and clinically studied for obesity, overweight with related conditions and type 2 diabetes, among other indications.
The active ingredient is described as a triple agonist because it simultaneously activates GIP, GLP-1 and glucagon receptors.
This distinguishes retatrutide from both classic GLP-1 receptor agonists and tirzepatide, which activates GIP and GLP-1 receptors.
You can find more information about the active ingredient on our retatrutide active ingredient page.
Retatrutide is currently not an approved medicine for routine use. Its mechanism of action and potential indications continue to be studied clinically.
This page is provided solely for factual information about its development status, mechanism of action, published study data and the safety information currently available.
Is Retatrutide Already Approved?
No. Retatrutide currently has no regular approval for the treatment of obesity, overweight or type 2 diabetes in Germany or the European Union.
Outside clinical trials, retatrutide is therefore not regularly available as a prescription medicine.
What Changed for Retatrutide in 2026?
Clinical development has progressed considerably since the Phase 3 programmes began. Positive results have now been reported from several pivotal trials, including TRIUMPH-1, TRIUMPH-2 and TRIUMPH-3.
Additional Phase 3 programmes continue to study retatrutide across obesity-related conditions, type 2 diabetes, cardiovascular and renal outcomes and other metabolic diseases. Despite these results, retatrutide remains an investigational medicine.
How Is Retatrutide Used in Clinical Trials?
Retatrutide is being studied in clinical development programmes as a subcutaneous injection. In the pivotal trials, it is administered once weekly.
As retatrutide is not approved, there is no regulatory-approved standard dosage for routine medical treatment.
Which Retatrutide Doses Have Been Studied?
Clinical programmes investigate different target doses. These are study doses and not approved treatment recommendations.
There is currently no approved dosage for retatrutide, no approved package information and no routine treatment regimen for patients.
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How Does Retatrutide Work and What Do Current Studies Show?
Retatrutide simultaneously activates receptors for GIP, GLP-1 and glucagon. This affects several metabolic and hormonal signalling pathways at once.
Studies are investigating effects on appetite, satiety, food intake, glucose metabolism and energy balance, among other factors.
What Did the Published Phase 2 Trial Show?
The Phase 2 trial published in the New England Journal of Medicine in 2023 included 338 adults with obesity or overweight without diabetes.
In the combined 8 mg groups, mean weight change was −22.8%, while the combined 4 mg groups achieved −17.1%. The trial was designed for dose finding and was not a registration trial.
What Did TRIUMPH-1 Show in 2026?
TRIUMPH-1 is a large Phase 3 trial in adults with obesity or overweight and at least one weight-related condition without type 2 diabetes.
Average weight changes of −25.9% with 9 mg and −19.0% with 4 mg were also reported. The Phase 3 results were presented by Eli Lilly in 2026. Positive trial results do not constitute marketing authorisation.
What Did TRIUMPH-4 Show in Obesity and Knee Osteoarthritis?
TRIUMPH-4 studied adults with obesity or overweight and knee osteoarthritis without diabetes.
Substantial improvements in WOMAC pain scores were also reported. These findings relate to a specific study population with knee osteoarthritis and should not be generalised to every individual.
What Side Effects Have Been Reported With Retatrutide So Far?
As retatrutide has not yet been approved, its safety assessment is based on clinical trials. The full safety profile has not yet been conclusively established.
What Did the Phase 2 Trial Show About Tolerability?
The most common adverse events were gastrointestinal. They occurred in a dose-dependent manner and were mostly mild to moderate in severity.
A lower starting dose partially reduced gastrointestinal adverse events in the trial.
In the Phase 2 trial, heart rate increased in a dose-dependent manner, peaked around week 24 and subsequently declined again. The clinical significance of these findings continues to be assessed in the development programme.
In TRIUMPH-1, altered skin sensations such as dysesthesia and urinary tract infections were also reported more frequently with retatrutide than with placebo. Most of these events were mild to moderate.
What Are the Contraindications for Retatrutide?
Therefore, there is also no regulatory-approved list of standard contraindications, dose adjustments or drug interactions for routine clinical use.
Exclusion criteria used in individual clinical trials should not be considered equivalent to future official product information.
Pregnancy and Breastfeeding
There is currently no approved use of retatrutide during pregnancy or breastfeeding. Clinical trials use their own inclusion and exclusion criteria.
As the active ingredient remains investigational, information from clinical trials should not be interpreted as general treatment guidance outside a study protocol.
Why Are Products From Unverified Online Sources Problematic?
A product sold online as “retatrutide” is not automatically an approved medicine with verified identity, purity, dosage or manufacturing quality.
As long as retatrutide does not have regular marketing authorisation, products claiming to contain retatrutide from uncontrolled sources should not be equated with the investigational drug used in clinical trials.
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How Does Retatrutide Differ From Other Medications?
Retatrutide differs from already approved weight-management medicines both in its mechanism of action and its development status.
Retatrutide in Comparison
Retatrutide vs. Wegovy
Triple agonist vs. GLP-1
Wegovy contains semaglutide and acts through the GLP-1 receptor.
Retatrutide additionally activates GIP and glucagon receptors. The regulatory difference is equally important: Wegovy is approved, while retatrutide is not.
Retatrutide vs. Mounjaro
GIP + GLP-1 + glucagon vs. GIP + GLP-1
Mounjaro contains tirzepatide and activates GIP and GLP-1 receptors.
Retatrutide additionally activates the glucagon receptor. Mounjaro already has EU approval for weight management in adults, while retatrutide remains in clinical development.
Retatrutide vs. Ozempic
investigational triple agonist vs. approved diabetes medicine
Ozempic contains semaglutide and is approved for the treatment of type 2 diabetes.
Retatrutide is also being studied in type 2 diabetes, but currently has no regular marketing authorisation for this indication.
More Questions About Retatrutide
Is Retatrutide Already Approved?
No. Retatrutide is currently not approved as a medicine in Germany or the European Union.
The active ingredient remains in clinical development.
Does The Body Clinic Offer Retatrutide?
No. The Body Clinic does not currently offer or prescribe retatrutide.
Can You Buy Retatrutide?
No regularly approved retatrutide medicine is currently available on the German pharmaceutical market.
Products offered online under the name retatrutide outside clinical trials should not be considered equivalent to an approved and regulatory-reviewed medicine.
When Could Retatrutide Be Approved?
There is currently no confirmed approval date.
In July 2026, Eli Lilly announced plans to submit a regulatory application for retatrutide to the FDA in the first quarter of 2027. This does not indicate when, or with what outcome, regulatory procedures in the US or Europe will be completed.
Is Retatrutide the Same as Mounjaro?
No. Mounjaro contains tirzepatide and activates GIP and GLP-1 receptors.
Retatrutide is a different active ingredient that additionally activates the glucagon receptor.
How Much Weight Did Participants Lose With Retatrutide?
In the published Phase 2 trial, the mean change in body weight at the highest dose studied was −24.2% after 48 weeks.
In the Phase 3 TRIUMPH-1 trial, an average weight change of −28.3% was reported with 12 mg after 80 weeks. These results relate to study populations and are not an individual prediction.
Is There an Official Retatrutide Dosage?
No. As retatrutide has not yet been approved, there is no officially approved dosage for patients.
Doses used in clinical trials are part of the respective study protocols and are not general treatment recommendations.
Sources on Retatrutide
- Jastreboff A. M., Kaplan L. M., Frías J. P. et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity: A Phase 2 Trial. New England Journal of Medicine. 2023;389:514–526. DOI: 10.1056/NEJMoa2301972. Peer-reviewed Phase 2 trial in adults with obesity or overweight without diabetes. View the Phase 2 trial.
- Rosenstock J., Frías J., Jastreboff A. M. et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes. The Lancet. 2023;402(10401):529–544. DOI: 10.1016/S0140-6736(23)01053-X. Peer-reviewed Phase 2 trial in adults with type 2 diabetes. View the diabetes trial.
- ClinicalTrials.gov, U.S. National Library of Medicine. TRIUMPH-1: A Study of Retatrutide in Participants Who Have Obesity or Overweight. ClinicalTrials.gov ID NCT05929066. Phase 3 trial with 2,335 participants. The primary study period was completed in 2026. View TRIUMPH-1 on ClinicalTrials.gov.
- Eli Lilly and Company. Retatrutide delivered powerful weight loss in pivotal Phase 3 obesity trial. Publication dated May 21, 2026 on the topline results from TRIUMPH-1. These data should be regarded as sponsor-reported Phase 3 results. View the TRIUMPH-1 results.
- ClinicalTrials.gov, U.S. National Library of Medicine. TRIUMPH-4: A Study of Retatrutide Once Weekly in Participants Who Have Obesity or Overweight and Osteoarthritis of the Knee. ClinicalTrials.gov ID NCT05931367. Completed Phase 3 trial. View TRIUMPH-4 on ClinicalTrials.gov.
- Eli Lilly and Company. Retatrutide delivered weight loss along with substantial relief from osteoarthritis pain in first successful Phase 3 trial. Publication dated December 11, 2025 on TRIUMPH-4. View the TRIUMPH-4 results.
- Eli Lilly and Company. Retatrutide successful in two additional Phase 3 obesity trials. Publication dated July 23, 2026 on TRIUMPH-2 and TRIUMPH-3 as well as the planned regulatory pathway. View the latest Phase 3 results.