Retatrutide
Also known as: LY3437943, triple agonist, GGG tri-agonist
By GLPeptideSciences Editorial Team · How we evaluate evidence · Reviewed by Dr. George S. Watson, MD, Cardiothoracic Surgeon · Updated 2026-06-02
An investigational triple agonist targeting the GLP-1, GIP and glucagon receptors, notable for unusually large weight reduction in early human trials.
What it is & how it works
What it is
Retatrutide is an investigational triple agonist — a single molecule designed to activate the GLP-1, GIP, and glucagon receptors. It is the next conceptual step beyond the dual agonist tirzepatide.
How it is thought to work
Adding glucagon-receptor activity to the incretin effects of GLP-1 and GIP is hypothesized to increase energy expenditure on top of appetite and glucose effects. That combination is the rationale for the large weight changes seen in early trials.
The evidence and the caveat
Phase-2 data was striking enough to make headlines, but “striking phase-2 result” is not “approved drug.” Phase-3 trials are ongoing, long-term safety is still being characterized, and there is no approved product — so any non-trial “retatrutide” is unapproved and unverified.
What it's discussed & studied for
- Obesity / weight management (investigational)
- Metabolic and liver outcomes (under study)
Discussion of a use is not a claim that it works or is approved.
Research status
Investigational. Phase-2 results drew major attention for the size of the weight effect; phase-3 trials are ongoing. Not approved.
Evidence quality
Human trial data exists and is promising, but it is not yet complete and the compound is not approved. Long-term safety is still being established.
Dosing discussion
Doses are defined only within clinical trials. There is no approved label, and any non-trial use is outside validated protocols.
Educational summary of what is discussed in the literature and community — not a dosing recommendation or medical advice.
Safety & harm reduction
Side effects in trials are predominantly gastrointestinal, consistent with the incretin class. Because it adds glucagon-receptor activity, its full profile is still being characterized in ongoing trials. Not approved for use.
Sourcing literacy
There is no approved product. Anything sold as 'retatrutide' on the research market is unapproved and unverified, with the usual identity/purity risks.
Selected literature
FAQ
Is retatrutide approved?
No. It is investigational and in ongoing trials. It is not approved for any use.
Why is it called a 'triple agonist'?
It activates three receptors — GLP-1, GIP and glucagon — whereas semaglutide hits one and tirzepatide two.