Semaglutide vs Tirzepatide
Compare the research, key figures and safety notes.
How they differ
Both are once-a-week shots that act on the body's gut-hormone signals for appetite and blood sugar. Semaglutide copies one of those signals (GLP-1); tirzepatide copies two (GLP-1 and GIP). Both stay in the body for several days, so a weekly dose holds a steady level rather than a spike. Both have been tested in people, with large published dose-finding trials behind their step-up schedules (STEP and SURMOUNT).
Side by side
| Measure | Semaglutide | Tirzepatide |
|---|---|---|
| Category | Metabolic | Metabolic |
| Evidence | A · Human dose research | A · Human dose research |
| Route | Subcutaneous | Subcutaneous |
| Half-life | 168 h | 120 h |
| Typical vial | 3 / 5 / 10 mg | 5 / 10 / 15 mg |
| Research amount | 0.25–2.4 mg | 2.5–15 mg |
| Common schedule | Once a week | Once a week |
| Cycle / break | Titrated | Titrated |
| Studied for | Metabolism and weight | Metabolism and weight |
These amounts and schedules are figures discussed in research and community reports, shared for learning — not a recommendation and not medical advice. A step-by-step dosing schedule exists only where a human trial backs it; the evidence tier tells you which.
Decay curves, overlaid
Each line is scaled to that compound's own first dose, so the chart shows how each one builds up over time — not how the compounds' doses compare to one another, which these different molecules share no common unit for.
How they combine
Educational reference on commonly-discussed combinations, not medical advice. Combining compounds can change how each behaves — read this as a prompt to research, not a clearance.