Semaglutide vs Tirzepatide
Semaglutide is FDA-approved and rated 5/5 for evidence; Tirzepatide is FDA-approved and rated 5/5. They have a similar amount of human evidence. Both are used for metabolic & weight goals.
| Compare | SemaglutideThe GLP-1 drug that started the modern weight-loss era: Ozempic and Wegovy. | TirzepatideThe dual GIP/GLP-1 agonist behind Mounjaro and Zepbound. |
|---|---|---|
| Category | Metabolic & Weight | Metabolic & Weight |
| Evidence | 5/5FDA-approved with large RCT programs (SUSTAIN, STEP, SELECT). SELECT showed a 20% reduction in major cardiovascular events in people with heart disease and overweight. | 5/5FDA-approved on the basis of large phase 3 programs (SURPASS for diabetes, SURMOUNT for obesity, SURMOUNT-OSA for sleep apnea). |
| FDA status | FDA-approved (Ozempic 2017, Wegovy 2021) | FDA-approved (Mounjaro 2022, Zepbound 2023) |
| WADA (sport) | Not prohibited | Not prohibited |
| Also known as | Ozempic, Wegovy, Rybelsus, NN9535, AMP-1 (SM) | Mounjaro, Zepbound, LY3298176, AMP-2 (TR) |
| How it works | A modified version of the natural hormone GLP-1 with a fatty-acid side chain that binds albumin, stretching its half-life to about a week. It lowers appetite through the brain, slows stomach emptying, and increases insulin release when blood sugar is high. | A 39-amino-acid peptide with a C20 fatty diacid at lysine-20 that binds albumin, so it lasts about 5 days. GLP-1 and GIP receptor activation lowers appetite, slows stomach emptying, and boosts insulin release when blood sugar is high. |
| Half-life | About 7 days (once-weekly dosing) | About 5 days (once-weekly dosing) |
| Commonly reported doses |
|
|
| Route | Subcutaneous (abdomen, thigh, upper arm) | Subcutaneous (abdomen, thigh, upper arm) |
| Good once mixed | ~28 days in the fridge | ~28 days in the fridge |
| Top side effects |
|
|
| Lowest price per mg | $3.00 (10 mg vial, 40% off) | $1.10 (60 mg vial, 40% off) |
| Latest lab purity | 99.17% (lot SEM0001) | 99.76% (lot TRZ0001) |
Want a third? Add another peptide. Doses are commonly reported ranges, not recommendations.

