Tirzepatide vs Retatrutide half-life
Tirzepatide has an elimination half-life of about 5 days; Retatrutide has about 6 days. Tirzepatide is a dual GIP/GLP-1 receptor agonist. Retatrutide, still in clinical trials, adds glucagon receptor activity, making it a triple agonist. Both are studied as once-weekly injections.
Side by side
| Tirzepatide | Retatrutide | |
|---|---|---|
| Half-life | 5 days | 6 days (range 5.6–6.9 days) |
| Route | SC weekly | SC weekly |
| Category | GLP-1 & incretins | GLP-1 & incretins |
| Evidence | Clinical | Limited |
| Remaining after 24 hours | 87.1% | 89.1% |
| Remaining after 7 days | 37.9% | 44.5% |
| ~97% cleared (5 half-lives) | 25 days | 30 days |
| Steady state (4-5 half-lives) | 20 days to 25 days | 24 days to 30 days |
Single-dose decay
Share of one dose remaining over time, assuming first-order elimination. Dashed lines mark each half-life.
Tirzepatide (t½ 5 days) Retatrutide (t½ 6 days)
Tirzepatide: FDA label: half-life of about 5 days. Retatrutide: Phase 1/2 trials: about 6 days.
FAQ
Which lasts longer, Tirzepatide or Retatrutide?
Retatrutide lasts longer. Its half-life is about 6 days, versus 5 days for Tirzepatide, roughly 1.2 times longer.
How long do Tirzepatide and Retatrutide stay in your system?
With first-order elimination, about 97% of a single dose is cleared after five half-lives: roughly 25 days for Tirzepatide and 30 days for Retatrutide. Individual clearance varies.
How long until Tirzepatide and Retatrutide reach steady state?
With consistent repeated dosing, levels approach steady state after 4 to 5 half-lives: about 20 days to 25 days for Tirzepatide, and 24 days to 30 days for Retatrutide.
How reliable are these half-lives?
Tirzepatide: Clinical evidence. Retatrutide: Limited evidence. Anecdotal values are community estimates and may be far off.