Research Use Only (RUO). This article is for education and shares what published science says about a research compound. It is not medical advice, and nothing here is a suggestion to use any peptide on people or animals.
If you have searched what is retatrutide, what is reta, or GLP-3, this guide gives a plain answer. Retatrutide (sometimes spelled retatrutide, reta, or written as GLP-3) is an investigational research peptide made by Eli Lilly. Here is what the published science says, in simple words.
What is retatrutide?
Retatrutide is a lab-made peptide. A peptide is a short chain of amino acids, the same building blocks that make proteins. Scientists study it because of how it acts on three receptors in the body at once. Its research code name is LY3437943. It is still being tested in clinical trials and is not an approved medicine.
Why do people call it GLP-3?
Online you will see GLP-3, glp3, or glucagon-like peptide-3 used for retatrutide. This is a nickname, not a real hormone name. There is no natural hormone called glucagon-like peptide-3. People use GLP-3 because retatrutide is seen as a next step after single and dual agonists. What retatrutide actually does is act on three targets: the GLP-1 receptor, the GIP receptor, and the glucagon receptor. That is why scientists call it a triple agonist.
How does retatrutide work in the research?
According to Eli Lilly, retatrutide combines glucagon receptor activity with GIP and GLP-1 receptor activity. In the published Phase 2 trial, this triple action was linked to large changes in body weight in adults with obesity. Researchers study each of the three pathways to understand how they add up.
What does the research say about results?
In the Phase 2 trial published in the New England Journal of Medicine, adults given retatrutide showed a mean weight reduction of up to 17.5% at 24 weeks and up to 24.2% at 48 weeks at the highest dose studied. In later Phase 3 TRIUMPH trials, reported reductions reached roughly 28-30%. These are trial findings in study participants, reported by the researchers - not a promise of any result.
Is retatrutide approved?
No. As of 2026, retatrutide is not FDA approved. It is still moving through Phase 3 clinical trials, and Drugs.com notes it is investigational. Any compound sold outside of a clinical trial is a research chemical, not an approved medicine.
Retatrutide research materials at Dissolv Labs
Dissolv Labs supplies high-purity compounds as reference materials for laboratory research only. They are not for human or animal use.
Frequently asked questions
Is reta the same as retatrutide?
Yes. Reta and reta peptide are short nicknames for retatrutide.
Is retatrutide a GLP-1?
It acts on the GLP-1 receptor plus two others (GIP and glucagon), so it is broader than a GLP-1-only compound.
Who makes retatrutide?
Eli Lilly and Company developed retatrutide (code LY3437943).
The bottom line
Retatrutide, or reta, is an investigational triple-agonist research peptide nicknamed GLP-3. Published trials report large weight changes in study participants, but it is not FDA approved and is sold only as a Research Use Only reference material.
Sources
- Eli Lilly: Phase 2 retatrutide results published in NEJM
- Jastreboff et al., Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial (NEJM, via PubMed)
- AJMC: Retatrutide achieves up to 30.3% average weight loss in Phase 3 TRIUMPH-1
- Drugs.com: Retatrutide history and FDA approval status
Disclaimer: All Dissolv Labs products are sold for Research Use Only and are not for human or veterinary use. This content is educational and is not medical advice, diagnosis, treatment guidance, or a recommendation to consume any substance.
