Retatrutide vs Tirzepatide
Retatrutide and Tirzepatide are the two most-studied incretin research compounds, and they are compared constantly because they differ by one receptor. Tirzepatide is a dual GIP/GLP-1 agonist; Retatrutide adds a third target, the glucagon receptor. That extra arm is the whole substance of the comparison, and it is also why the two sit at different stages of the published literature.
Retatrutide
A triple agonist acting at the GLP-1, GIP and glucagon receptors — the added glucagon arm is what distinguishes it.
BEST STUDIED FOR
Triple-agonist receptor research
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Tirzepatide
A dual agonist acting at the GIP and GLP-1 receptors, with the larger completed clinical dataset of the two.
BEST STUDIED FOR
Dual-agonist body-composition research
R699View product →
SIDE BY SIDE
| Retatrutide | Tirzepatide | |
|---|---|---|
| Receptor targets | GLP-1 + GIP + glucagon (triple agonist) | GIP + GLP-1 (dual agonist) |
| The distinguishing arm | Glucagon-receptor agonism, studied for energy expenditure | None — the dual mechanism is the established one |
| Stage of published evidence | Phase 2 (NEJM 2023, Jastreboff), n=338 | Phase 3 programme complete, incl. a SURMOUNT-1 DXA substudy |
| Reported body-weight change | -17.5% mean at 24 weeks; -24.2% at 48 weeks (12 mg arm) | -21.3% at 72 weeks (DXA substudy, n=160) |
| Reported body-composition detail | Not separated by DXA in the Phase 2 report | -33.9% total fat mass vs -8.2% placebo; ~75% of loss was fat |
| Note on the two figures | Body WEIGHT percentage | Body FAT-MASS percentage — a different quantity, and the two are routinely conflated |
| Supplied as | 30 mg lyophilised vial, HPLC-verified with a batch CoA | 30 mg lyophilised vial, HPLC-verified with a batch CoA |
WHEN TO RESEARCH WHICH
Tirzepatide has the deeper published record — a completed Phase 3 programme with a DXA substudy that separated fat mass from lean mass. Retatrutide is earlier: a Phase 2 dataset, with a third receptor arm whose contribution is still being characterised. Neither is a treatment, neither is approved for human use here, and both are supplied strictly for laboratory research. Evidence on the triple agonist in particular is preliminary.
FREQUENTLY ASKED
What is the difference between Retatrutide and Tirzepatide?
The number of receptors. Tirzepatide is a dual agonist at the GIP and GLP-1 receptors. Retatrutide is a triple agonist, adding the glucagon receptor, which is studied for its role in energy expenditure. Everything else about the comparison follows from that one difference.
Which has more published evidence?
Tirzepatide, clearly. Its Phase 3 programme is complete and includes a DXA substudy (Look et al., Diabetes Obes Metab 2025, n=160) that measured fat mass separately from body weight over 72 weeks. Retatrutide's main dataset is the Phase 2 trial published in NEJM in 2023 (Jastreboff et al., n=338). Evidence on the triple agonist is preliminary.
Are the percentage figures comparable?
No, and this is the most common error made with these two compounds. Retatrutide's widely quoted -17.5% at 24 weeks is a BODY-WEIGHT figure. Tirzepatide's -33.9% is a BODY-FAT-MASS figure from a DXA substudy. They measure different things over different timeframes and cannot be set side by side as if they were the same number.
Are these supplied for human use?
No. Both are supplied strictly for laboratory research purposes only. They are not approved medicines in South Africa, they are not prescribed or dispensed here, and nothing on this page is medical advice. Every vial is HPLC-verified with a batch Certificate of Analysis.
MORE COMPARISONS
All products supplied for research purposes only. Not for human consumption.