Multi-way comparison
Semaglutide vs Tirzepatide vs Retatrutide
Side by side from the same data: half-life, evidence tier, research amounts, common schedule, and every decay curve on one chart.
How they differ
A plain-language read of what actually sets them apart. Reference only, not medical advice.
These three add one copied gut-hormone signal at a time. Semaglutide copies one (GLP-1), tirzepatide copies two (GLP-1 and GIP), and retatrutide copies three (adding glucagon) and has been studied at higher doses. All three are once-a-week shots that stay in the body for days, so each builds to a steady weekly level. All have been tested in people — but semaglutide and tirzepatide are licensed medicines, while retatrutide's evidence so far is a mid-stage (phase-2) weight study.
Side by side
Every figure is drawn from this site's own compound data — the same numbers on each compound's page.
| Measure | Semaglutide | Tirzepatide | Retatrutide |
|---|---|---|---|
| Category | Metabolic | Metabolic | Metabolic |
| Evidence | A · Tested in people | A · Tested in people | A · Tested in people |
| Route | Subcutaneous | Subcutaneous | Subcutaneous |
| Half-life | 168 h | 120 h | 144 h |
| Typical vial | 3 / 5 / 10 mg | 5 / 10 / 15 mg | 5 / 10 mg |
| Research amount | 0.25–2.4 mg | 2.5–15 mg | 0.5–12 mg |
| Common schedule | Once a week | Once a week | Once a week |
| Cycle / break | Titrated | Titrated | Titrated |
| Studied for | Metabolism and weight | 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
Every compound on one chart — something the single-compound pages cannot show.
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
Where two of these have a documented pairing in this reference.
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.
- Semaglutide + TirzepatideTwo incretin agonists on the same receptor — the combination adds gastrointestinal effects, not benefit, in research reports.Avoid combination
- Semaglutide + RetatrutideBoth drive GLP-1 receptor agonism, so running them together doubles the same mechanism rather than adding a new one.Avoid combination
- Tirzepatide + RetatrutideOverlapping GLP-1 receptor agonism; stacking incretin agonists compounds gastrointestinal load without adding a mechanism in research reports.Avoid combination