Comparison
Retatrutide vs. Tirzepatide (Mounjaro / Zepbound)
Retatrutide or tirzepatide – which works better, and which is approved?
The short answer
Tirzepatide has been approved in the EU as Mounjaro since 2022 for type 2 diabetes and weight management. In SURMOUNT-1, people without diabetes lost up to 20.9 percent of their weight after 72 weeks, and SURPASS-CVOT showed non-inferiority to dulaglutide for cardiovascular events but missed superiority. Retatrutide additionally acts on the glucagon receptor and reached 25.0 percent versus 3.9 percent on placebo after 80 weeks in the phase 3 trial TRIUMPH-1. There is no head-to-head comparison; the idea that retatrutide works better rests on placing separate trials side by side. Retatrutide is not approved anywhere, long-term data are missing, and grey-market products are not the study drug. Both are medicines, and the decision belongs in a doctor's hands.
The numbers side by side
| Axis | Retatrutide | Tirzepatide (Mounjaro / Zepbound) | Difference |
|---|---|---|---|
| Human evidenceHow much and how good the data in humans are | 9 | 10 | Tirzepatide better studied |
| MechanismHow well the chain of action is understood | 8 | 9 | Tirzepatide better studied |
| Safety dataHow well safety has been studied – not how safe it is | 7 | 8 | Tirzepatide better studied |
| Hype gap10 means: the advertising stays level with the data | 4 | 7 | Tirzepatide closer to the data |
| Track record of useHow much documented use in humans exists – does not measure whether it works | 4 | 8 | Tirzepatide in use longer |
| Rating | Well supported, heavily overhyped · Well supported | ||
“Track record of use” measures how long and how widely something has been used in humans – not whether it works. The BK-Score is a subjective assessment by Biohacking Kompakt based on published scoring rules (German). It is not a scientific rating, not the consensus of a professional society and not a medical recommendation.
Why these numbers
Retatrutide
The strongest weight data ever collected, now also peer-reviewed in phase 3. Phase 2: 338 participants, 48 weeks, 24.2 percent versus 2.1 percent on placebo (NEJM 2023). TRIUMPH-1 (NEJM 2026): 2,339 participants without diabetes, 80 weeks, double-blind, 25.0 percent at the highest dose versus 3.9 percent on placebo, calculated across all randomized participants; according to the manufacturer, 28.3 percent among everyone who continued treatment as planned. Also peer-reviewed are TRIUMPH-2 in type 2 diabetes (Lancet 2026, 18.8 versus 5.1 percent) and the diabetes trial TRANSCEND-T2D-1 (Lancet 2026). According to the manufacturer, TRIUMPH-4 reached 28.7 percent versus 2.1 percent on placebo with 445 participants over 68 weeks. Triple agonism is demonstrated in humans; the contribution of the glucagon arm has not been tested separately. The price is in the same trials: nausea in up to 43.2 percent (highest dose in TRIUMPH-4) and discontinuation due to side effects in up to 18.2 percent. Safety 7 (previously 6): these data now come from several peer-reviewed phase 3 trials, TRIUMPH-1 alone with 2,339 participants over 80 weeks; for a higher score, long-term data from approval and pharmacovigilance are missing. There is no approval yet; what is traded on the grey market today is not the study drug.
Tirzepatide (Mounjaro / Zepbound)
Approved on the basis of the SURMOUNT and SURPASS programmes; the dual receptor action is demonstrated in humans. Fewer long-term data than for semaglutide, because it is newer. Coverage by statutory health insurance is excluded – this gets glossed over in advertising.
Frequently asked questions
Is retatrutide stronger than tirzepatide?
According to the published figures, trial participants lose more weight on retatrutide: 25.0 percent after 80 weeks in TRIUMPH-1, calculated across all randomized participants, versus up to 20.9 percent after 72 weeks in SURMOUNT-1 with tirzepatide. These trials ran separately and for different lengths of time. There is no head-to-head trial, and how much the third lever, the glucagon receptor, contributes on its own has not yet been tested separately.
Is retatrutide approved like tirzepatide?
No. The European Medicines Agency approved tirzepatide as Mounjaro on 15 September 2022 for type 2 diabetes and weight management; it is prescription-only, and German statutory health insurance does not cover it for weight reduction. Retatrutide is not approved anywhere in the world; Eli Lilly plans to file with the FDA in the first quarter of 2027. In Germany it is not a marketable medicine, and in sport it falls under class S0 of the WADA Prohibited List.
What side effects do retatrutide and tirzepatide have?
For both, gastrointestinal complaints are the main issue. With retatrutide they are more pronounced: nausea in 42.4 percent at the highest dose in TRIUMPH-1 according to the manufacturer, and discontinuation due to side effects of up to 18.2 percent in TRIUMPH-4. New are dysaesthesia, meaning abnormal skin sensations, and a higher heart rate from the glucagon arm. For tirzepatide, the loss of lean mass has been quantified at 25.4 percent of weight lost. Long-term data on retatrutide are missing.
What about retatrutide bought online?
What is sold as retatrutide on the grey market is not the study drug and has not been tested; the FDA has warned about such products. A preprint that has not been peer-reviewed found 7.2 percent weight loss after six to twelve months in people who obtained retatrutide outside a trial, versus 15.5 percent in trial participants. That was roughly the level of comparable tirzepatide users at 7.7 percent. One case report describes impending ketoacidosis after retatrutide bought online.
See all ratings in the ranking (German app)
Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in a doctor's hands.