Peptide half-life calculator
Choose a peptide and an interval to estimate how much of one dose remains in the blood. The calculator preserves both ends of a measured half-life range. It does not recommend a dose or schedule.
In this tool
Calculator
5.8–8.1 days
Recorded from Teichman et al. 2006. The band below is computed from both ends of it.Still present when the next dose lands
88.7% to 91.8%
Between 0.12 and 0.17 half-lives have elapsed by then. The two ends of the answer are the two ends of the recorded half-life: the longer figure leaves more behind.
- Our arithmetic, not anybody’s label
- 0.5 ^ (1 day ÷ 8.1 days) = 0.5 ^ 0.12
0.5 ^ (1 day ÷ 5.8 days) = 0.5 ^ 0.17 - Interval
- 1 day
Where the recorded half-life is a range, the result is a range too. This models the blood clearance of one dose, not how long a treatment works.
Reference table
Compare the estimated amount remaining after each interval. These examples describe blood clearance; they are not recommended schedules and do not establish an appropriate dose.
The table scrolls sideways; the first column stays put.
| Molecule | every 8 hours | every 12 hours | once a day | every 2 days | once a week |
|---|---|---|---|---|---|
| Sermorelin10–20 min | below 0.01% | below 0.01% | below 0.01% | below 0.01% | below 0.01% |
| Tesamorelin8 min | below 0.01% | below 0.01% | below 0.01% | below 0.01% | below 0.01% |
| Ipamorelin~2 hours | 6.25% | 1.56% | 0.024% | below 0.01% | below 0.01% |
| CJC-1295 + DAC5.8–8.1 days | 96.1% to 97.2% | 94.2% to 95.8% | 88.7% to 91.8% | 78.7% to 84.3% | 43.3% to 54.9% |
Half-life from the labels and trials on the sources page, both ends of every range. CJC-1295 (no DAC) has no row: no human study reports a half-life to divide.
How it works
The estimate uses exponential decay: remaining = 0.5 ^ (interval ÷ half-life). That is plain exponential decay — after one half-life half the dose is left, after two a quarter, and so on. The number of half-lives elapsed is the interval divided by the half-life, and the result shows that number alongside the percentage.
Where the half-life is a range, the calculation is repeated at each end. The longer end leaves more behind, so the result preserves both ends of the measured range.
Below 0.01% this page stops printing a percentage and says “below 0.01%” instead. A figure with twenty leading zeros is arithmetic about an exponential rather than something a reader can use, and it implies a precision the underlying half-life — itself a span — does not have. The threshold is printed rather than hidden so it can be checked.
What the result means
It is not a dosing schedule and it does not compute a dose. The output is a fraction of whatever was given, and nothing on this page says how much of anything to inject or how often. Nothing here is medical advice; a schedule is a question for a licensed clinician — see the medical disclaimer.
It models one dose, not a course. Repeated dosing can cause accumulation. This estimate does not model the total amount present across repeated doses.
The evidence limits the estimate. Where a label or a trial reports a range, both ends remain visible in the result. Where no study reports a figure at all — CJC-1295 (no DAC) — there is no row and no button, because there is nothing to divide.
Sources
The documents below support the measured half-lives used in this calculator.
9 documents, in the order the figures above use them. The date on each is the one printed on the document.
- Esposito P, Barbero L, Caccia P, Caliceti P, D'Antonio M, Piquet G, Veronese FM. PEGylation of growth hormone-releasing hormone (GRF) analogues.Document date: 2003-09-26. PMID 14499707, doi:10.1016/s0169-409x(03)00109-1.
- Food and Drug Administration, Department of Health and Human Services. Determination That GEREF (Sermorelin Acetate) Injection, 0.5 Milligrams Base/Vial and 1.0 Milligrams Base/Vial, and GEREF (Sermorelin Acetate) Injection, 0.05 Milligrams Base/Amp, Were Not Withdrawn From Sale for Reasons of Safety or Effectiveness.Document date: published 2013-03-04, signed 2013-02-26. 78 FR 14095, FR Doc. 2013-04827, Docket No. FDA-2012-P-1071.
- Dominikowski A, Rękoś Z, Olejarz M, Szczepanek-Parulska E, Domin R, Ruchała M. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration.Document date: 2026-06-18. PMID 42395176, PMC13322892, doi:10.3389/fendo.2026.1822475.
- Theratechnologies Inc., prescribing information approved by the Food and Drug Administration. EGRIFTA SV (tesamorelin) for injection, for subcutaneous use — full prescribing information.Document date: label face date: Revised 03/2024; label version published 2026-07-31. SPL set id 3d783378-b02d-4f19-99dd-0fc91a042224, Initial U.S. Approval 2010.
- Theratechnologies Inc., prescribing information approved by the Food and Drug Administration. EGRIFTA WR (tesamorelin) for injection, for subcutaneous use — full prescribing information.Document date: label face date: Revised 03/2025; label version published 2026-08-03. SPL set id 839334d3-8c1d-4c26-9036-2ab524a6ea75, Initial U.S. Approval 2010.
- Venkova K, Mann W, Nelson R, Greenwood-Van Meerveld B. Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus.Document date: 2009-06. PMID 19289567, doi:10.1124/jpet.108.149211.
- Gobburu JV, Agersø H, Jusko WJ, Ynddal L. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers.Document date: 1999-09. PMID 10496658, doi:10.1023/a:1018955126402.
- Raun K, Hansen BS, Johansen NL, Thøgersen H, Madsen K, Ankersen M, Andersen PH. Ipamorelin, the first selective growth hormone secretagogue.Document date: 1998-11. PMID 9849822, doi:10.1530/eje.0.1390552.
- Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults.Document date: 2006-03. PMID 16352683, doi:10.1210/jc.2005-1536.