What is retatrutide?
Retatrutide is an experimental medication developed by Eli Lilly, the same company behind Mounjaro. It's described as a "triple agonist" because it's designed to act on three separate hormone receptors at once — GIP, GLP-1, and glucagon — rather than the one or two targeted by currently approved GLP-1 medications. It is being studied for both weight management and type 2 diabetes.
As of August 2026, retatrutide has not been approved or registered by any regulator anywhere in the world, including the U.S. FDA and South Africa's SAHPRA. It remains an investigational compound available only to participants in clinical trials.
Phase 3 trial results so far
Eli Lilly's Phase 3 program for retatrutide spans several trials under the TRIUMPH and TRANSCEND names, covering obesity, type 2 diabetes, and cardiovascular risk populations. Headline results reported through mid-2026 include:
TRIUMPH-1 — obesity, pivotal trial
Topline results reported 21 May 2026, from 2,339 participants over 80 weeks. Average weight loss reached approximately 19% at the 4mg dose, 26% at the 9mg dose, and up to roughly 28–30% at the highest 12mg dose — with some participants with severe obesity losing up to 30% of body weight over two years. The placebo group lost approximately 2–4%.
TRIUMPH-4 — obesity with knee osteoarthritis
Results reported December 2025 showed the 12mg dose produced an average 28.7% weight loss over 68 weeks, alongside a notable reduction in osteoarthritis knee pain among participants.
TRANSCEND-T2D-1 — type 2 diabetes
Topline results reported 19 March 2026: the 12mg dose produced 16.8% weight loss over 40 weeks along with a 2.0 percentage point reduction in HbA1c.
TRIUMPH-2 and TRIUMPH-3 — type 2 diabetes and cardiovascular disease
Results reported 23 July 2026 showed average weight loss of 20.8% (TRIUMPH-2) and 22.6% (TRIUMPH-3) at the 12mg dose in these populations.
Sleep apnea sub-study
Data presented at the ADA scientific sessions in June 2026 showed a 60.6% reduction in the apnoea-hypopnoea index among participants with severe obstructive sleep apnoea.
Side effects
Across the reported trials, side effects have been predominantly gastrointestinal — nausea, diarrhoea and similar — and mostly mild. Discontinuation due to side effects has reportedly been uncommon.
These are still trial results, not real-world outcomes
Clinical trial figures reflect controlled study conditions and specific participant groups. They should not be read as a guarantee of individual results, and none of this data changes the fact that retatrutide is not yet an approved medication.
Regulatory status and timeline
Eli Lilly has indicated it plans to submit a Biologics License Application (BLA) — the FDA approval pathway used for biologic medications like retatrutide — in Q1 2027, a timeline pushed back from an earlier Q4 2026 target. Until a regulator approves it, retatrutide cannot legally be prescribed, dispensed or sold anywhere, including South Africa.
We do not list any suppliers, importers or sources for retatrutide on this site, and we won't until it has a registered, legal path to market in South Africa. If you see it offered for sale anywhere today, treat that as a serious red flag — see our guide on buying GLP-1 medications legally in South Africa.
What this means if you're considering weight-loss treatment now
If you're weighing up options today, retatrutide isn't one of them yet. Currently registered alternatives available in South Africa include Ozempic, Wegovy, Mounjaro and Saxenda — each with its own approved indication, dosing schedule and pricing. Speak to a registered healthcare provider about which, if any, is appropriate for you.