RT-GLP1 and tirzepatide are both incretin-based peptides developed by Eli Lilly. The key difference is how many hormone receptors each one targets.
| RT-GLP1 | Tirzepatide | |
|---|---|---|
| Receptors | GLP-1, GIP and glucagon (triple) | GLP-1 and GIP (dual) |
| Status | Investigational, not licensed anywhere | Licensed prescription medicine, including in the UK |
| Clinical programme | Phase 3 TRIUMPH | SURPASS and SURMOUNT |
| Supplied by us | Yes, for research only | No |
The glucagon difference
Tirzepatide acts on the GLP-1 and GIP receptors. RT-GLP1 adds activity at the glucagon receptor, which is involved in energy use and the liver. That third pathway is the main reason researchers compare the two.
Where semaglutide fits
Semaglutide acts on the GLP-1 receptor only, so the three form a single, dual and triple agonist series. Onyx Peptides does not supply semaglutide or tirzepatide, which are licensed prescription medicines in the UK.
Frequently asked questions
What is the main difference between RT-GLP1 and tirzepatide?
Tirzepatide targets two receptors (GLP-1 and GIP). RT-GLP1 targets those two plus the glucagon receptor.
Is RT-GLP1 licensed like tirzepatide?
No. Tirzepatide is a licensed prescription medicine. RT-GLP1 is still investigational and not licensed anywhere.
Do you sell tirzepatide?
No. We supply RT-GLP1 for research only.
