Comparison
Semaglutide vs tirzepatide
Both are once-weekly incretin agonists approved for weight management. The difference is how many receptors each one acts on, and what that does to the dosing scale.
These two are the most compared compounds in the category, and the comparison is unusually well grounded: both hold regulatory approval, both have large published trials, and one head-to-head programme exists. That is not true of most pairings discussed on this site.
The practical differences come down to three things: how many receptors each acts on, the scale doses are measured on, and the side-effect pattern reported in trials.
| Attribute | Semaglutide | Tirzepatide |
|---|---|---|
| Receptor targets | GLP-1 only | GLP-1 and GIP |
| Evidence level | Approved, large phase 3 programme | Approved, large phase 3 programme |
| Dosing frequency | Once weekly | Once weekly |
| Half-life | About 7 days | About 5 days |
| Dose scale | Micrograms. 250 mcg to 2.4 mg weekly in trials | Milligrams. 2.5 mg to 15 mg weekly in trials |
| Average weight reduction in trials | Around 15% of body weight at the highest dose over 68 weeks | Around 21% of body weight at the highest dose over 72 weeks |
| Most common reported side effects | Nausea, diarrhoea, constipation, worst during dose increases | Nausea, diarrhoea, constipation, worst during dose increases |
| Typical vial sizes sold | 2 mg to 10 mg | 5 mg to 60 mg |
Things worth knowing
- The dose scales differ by roughly a factor of ten, which makes unit confusion between the two a realistic error. A tirzepatide dose entered in micrograms — or a semaglutide dose entered in milligrams — produces a wrong answer that can look plausible. The calculator flags a dose larger than the vial for exactly this reason.
- Trial figures are averages under supervised protocols with dietary support, not expected outcomes for an individual.
- They act on the same receptor, so they are alternatives rather than a stack. Running both duplicates a mechanism and compounds the gastrointestinal effects.
- Both are approved prescription medicines. A research-labelled vial has no manufacturing standard behind it and is not what either approval covers.
Full profile
Semaglutide
A long-acting GLP-1 receptor agonist approved for type 2 diabetes and for weight management, dosed once weekly.
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.
References
- Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). New England Journal of Medicine, 2022.
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.