Retatrutide half-life

Retatrutide has an elimination half-life of approximately 150 hours (about 6.3 days). Here is what that means for how long a single dose stays in your system.

Simple single‑compartment elimination model ((1/2)^t/t½): it ignores absorption, route, and individual variation, so treat it as a shape, not a measurement. In the Peptilot app this curve is stacked across your actual logged doses.

Clearance milestones

Milestone	Time after a single dose
50% eliminated	~6.3 days
75% eliminated	~12.5 days
90% eliminated	~21 days
~97% eliminated (≈5 half-lives)	~31 days

Evidence and source context

Regulatory status: Investigational. As of July 2026, retatrutide is not approved for public use and is available only through clinical research.
Evidence status: Human phase 2 publications and phase 3 topline results; safety and efficacy evaluation is ongoing.
Half-life context: The published phase 2 study describes dose-proportional pharmacokinetics and an approximate six-day half-life after subcutaneous administration. The chart is a simplified educational estimate.

Primary and official sources

Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 TrialNew England Journal of Medicine · Primary study
What to know about retatrutideEli Lilly and Company · Official status

Sources checked July 24, 2026 by the Peptilot editorial team. Independent medical review is pending; this page is educational and is not a treatment recommendation for Retatrutide.

About Retatrutide

Retatrutide is an investigational triple agonist of the GIP, GLP-1, and glucagon receptors that has appeared in clinical research on metabolic health and body weight. As an experimental compound it has not completed the full regulatory approval process. This entry is informational and is not a recommendation to use the compound.

See the full Retatrutide compound page or the Retatrutide reconstitution calculator, or compare against other compounds on the half-life overview.

Questions, answered.

What is Retatrutide's half-life?

Retatrutide's elimination half-life is approximately 150 hours (about 6.3 days), based on published pharmacokinetic data. That means about half of a dose is eliminated in that time, half of the remainder in the next interval, and so on.

How long does Retatrutide stay in your system?

Using the ~5-half-lives rule of thumb, a single dose of Retatrutide is roughly 97% eliminated after ~31 days. Actual clearance varies with dose history, route, and individual metabolism — treat this as an educational estimate, not a measurement.

Do levels build up with repeated doses?

Yes — if a new dose lands before the previous one is eliminated, the remainders stack. With consistent dosing, estimated levels reach steady state after roughly four to five half-lives. Peptilot's Levels feature stacks this exact curve across your logged doses so you can see the estimate for your own history.

Educational information for people who track their protocols — not medical advice, and never a recommendation to use any compound. Always work with a qualified healthcare provider.

Peptilot charts your estimated Retatrutide levels from the doses you actually log — in any browser, free for your first 3 days.

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