Comparison
Tirzepatide vs retatrutide
Two and three receptors respectively. Retatrutide reported the larger weight reduction; tirzepatide has a completed phase 3 programme and an approval. This is a different kind of claim.
Retatrutide's phase 2 results are the most striking numbers in this category: roughly 24% mean weight reduction at 48 weeks. Tirzepatide's phase 3 figures are lower, around 21% at the highest dose over 72 weeks.
Reading those side by side and concluding retatrutide is better is the mistake this page exists to prevent. A phase 2 trial in a few hundred people establishes a signal worth pursuing. A completed phase 3 programme with a regulatory review establishes something closer to a safety profile. Those are different questions, and the second one is the one that takes years.
Retatrutide adds glucagon receptor agonism as its third target, and that addition brought a heart rate increase with it. That is the specific thing longer-term data would need to characterise.
| Attribute | Tirzepatide | Retatrutide |
|---|---|---|
| Receptor targets | GLP-1 and GIP | GLP-1, GIP and glucagon |
| Evidence level | Approved — phase 3 completed | Early human. One published phase 2 |
| Best published result | About 21% mean weight reduction at 15 mg over 72 weeks, n = 2539 | About 24% mean weight reduction at 12 mg over 48 weeks, n = 338 |
| Regulatory status (US) | Approved prescription medicine | Investigational, no approval anywhere |
| Half-life | About 5 days | About 6 days |
| Distinct safety consideration | Gastrointestinal effects, gallbladder, pancreatitis | The above plus observed heart rate increases from glucagon agonism |
| Long-term data | Yes. Phase 3 programme with regulatory review | None |
Things worth knowing
- Sample size is the difference people skip past: 2,539 against 338. Larger trials find rarer problems, and rarer problems are what long-term safety is made of.
- The heart rate increase seen with retatrutide is mechanistically expected from glucagon receptor activity, which makes it a thing to characterise rather than dismiss.
- These act on overlapping receptors. They are alternatives, not a stack.
- Both are dosed in milligrams. Entering either in micrograms is a thousandfold error, and the calculator refuses a dose larger than the vial for exactly this reason.
- Tirzepatide is an approved prescription medicine. Buy it as a research chemical and the trial evidence stays behind with the product it was generated on.
Full profile
Tirzepatide
A once-weekly dual agonist that activates both the GIP and GLP-1 receptors, approved for type 2 diabetes and for weight management.
Full profile
Retatrutide
An investigational once-weekly triple agonist acting on the GLP-1, GIP and glucagon receptors. Not approved anywhere.
Related
This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on Bioalmanac is medical advice.