Peptide half-life calculator
How long does a compound actually stay in your system? These charts draw the elimination curve from published half-life data — the same math behind Peptilot's live level tracking.
Example: Semaglutide (t½ ≈ 165 hours (about 6.9 days))
Half-lives at a glance
| Compound | Half-life | ~97% eliminated after |
|---|---|---|
| Semaglutide | 165 hours (about 6.9 days) | ~34 days |
| Tirzepatide | 120 hours (about 5 days) | ~25 days |
| Retatrutide | 150 hours (about 6.3 days) | ~31 days |
| Liraglutide | 13 hours | ~2.7 days |
| BPC-157 | 4 hours | ~20 h |
| TB-500 (Thymosin Beta-4) | 60 hours (about 2.5 days) | ~12.5 days |
| GHK-Cu | 1 hour | ~5 h |
| Ipamorelin | 2 hours | ~10 h |
| CJC-1295 | 30 hours | ~6.3 days |
| Sermorelin | about 12 minutes | ~1 h |
| Tesamorelin | about 30 minutes | ~2.5 h |
| MK-677 (Ibutamoren) | 24 hours | ~5 days |
| MOTS-c | about 30 minutes | ~2.5 h |
| AOD-9604 | 1 hour | ~5 h |
| PT-141 (Bremelanotide) | 2.7 hours | ~14 h |
| Melanotan II | 1 hour | ~5 h |
Published elimination half-lives; single-dose figures. Individual clearance varies — these are educational estimates, not measurements or guidance.
Questions, answered.
What is a half-life?
A compound's elimination half-life (t½) is the time it takes for the amount in your body to fall by half. After one half-life 50% remains, after two 25%, after three 12.5% — and after about five half-lives a single dose is roughly 97% eliminated.
How long does a compound stay in your system?
A common rule of thumb is about five half-lives for a single dose to be ~97% eliminated. For a long-acting compound like semaglutide (t½ ≈ 165 hours) that's roughly a month; for a short one like BPC-157 (t½ ≈ 4 hours) it's under a day. Real clearance varies by person, dose history, and route.
Why do levels build up with repeated doses?
If you dose again before the previous dose is eliminated, the remainders stack. With regular dosing, levels climb until intake and elimination balance out — reaching steady state after roughly four to five half-lives of consistent dosing. This is why long half-life compounds are commonly dosed weekly.
How accurate are these curves?
They use a simple single-compartment elimination model on published half-life figures. That ignores absorption, bioavailability, route, and individual variation — so read them as the shape of elimination, not a measurement of your blood levels, and never as dosing guidance.
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 stacks these curves across your actual logged doses — see your estimated levels today, not just the theory.