Peptide Half-Life Calculator
Predict remaining concentration over time for 13+ research peptides using published half-life ranges. First-order decay model. Includes citations.
Research Reference Only — Not Dosing Guidance
Half-life values describe published in-solution or plasma decay observations for laboratory research reference. Orion products are for in-vitro research use only — not FDA-approved, not for human consumption. See the disclaimer.
Predicted decay curve
Reference: Sikiric et al., Curr Pharm Des, multiple reviews 2010-2020. Values describe published in-solution or plasma half-life observations for research reference only. Not dosing guidance, not clinical recommendation. See full disclaimer.
Methodology
Each compound's half-life entry is the midpoint of a literature range drawn from peer-reviewed sources or FDA-published clinical pharmacology data. The calculator applies first-order exponential decay:
C(t) = C₀ × (½)t / t½
Where C₀ is the initial quantity, t is elapsed time in hours, and t½ is the half-life. Output is the predicted remaining quantity in the same units as the input.
Half-life depends on route (IV / SC / IM / intranasal), formulation (free peptide vs analogue vs lipidated), and model (cell culture, animal, human). The range column on each entry reflects the spread across credible sources. For experiment-critical work, always cite the primary publication directly.
Published Half-Life Reference
| Compound | Half-Life (mid) | Literature Range | Source |
|---|---|---|---|
| BPC-157 | 5h | 4h – 6h | Sikiric et al., Curr Pharm Des, multiple reviews 2010-2020 |
| TB-500 | 2.5h | 2h – 3h | Crockford et al., Ann N Y Acad Sci 2010 |
| Retatrutide | 144h | 120h – 168h | Coskun et al., Cell Metabolism 2022 |
| Tirzepatide | 120h | 108h – 132h | Coskun et al., Mol Metab 2018; clinical trial PK data |
| Semaglutide | 165h | 155h – 184h | Knudsen et al., J Med Chem 2019 |
| GHK-Cu | 3h | 2h – 4h | Pickart et al., Skin Pharmacol 2008 reviews |
| MOTS-c | 15 min | 0.15h – 0.5h | Lee et al., Cell Metab 2015 |
| Tesamorelin | 27 min | 0.3h – 0.7h | Falutz et al., NEJM 2007 |
| Melanotan II | 51 min | 0.5h – 1.2h | Dorr et al., Life Sci 1996 |
| Selank | 9 min | 0.08h – 0.3h | Kozlovskaya et al., Eksp Klin Farmakol 2003 (free peptide; intranasal absorption differs) |
| DSIP | 7 min | 0.07h – 0.2h | Schoenenberger, Eur Neurol 1984 reviews |
| Adamax | 3h | 2h – 4h | Adamantane modification extends parent Semax half-life; published characterizations limited |
| NAD+ | 12 min | 0.1h – 0.5h | Cantó et al., Cell Metab 2012; tissue half-life longer than plasma |
FAQ
What does this calculator predict?
It applies the first-order decay equation C(t) = C₀ × (½)^(t/t½) to estimate how much of an initial peptide quantity remains after a given elapsed time. The half-life value used is the midpoint of a literature range for each compound. The result is a research reference value for in-solution or plasma decay, not a clinical recommendation.
Why are half-life ranges so wide?
Reported half-life varies with route (intravenous, subcutaneous, intranasal), formulation (free peptide vs analogue), model system (in-vitro stability vs in-vivo plasma), and the assay used. The range column reflects the spread across credible peer-reviewed sources. Always cite the underlying paper, not this tool.
Does this account for in-vivo metabolism?
Only indirectly. Some published half-lives are in-vitro stability measurements; others are plasma elimination half-lives in animal or human studies. The calculator uses whichever value the literature reports for that compound. It does not model species differences, protein binding, tissue redistribution, or pathway-specific metabolism.
Is this dosing guidance?
No. This is a research utility for predicting in-solution concentration decay or planning timecourse experiments in laboratory research contexts. Orion products are for in-vitro research use only and are not for human consumption.
What if my peptide isn't listed?
The list covers the compounds we stock that have published half-life data. If you need a compound not listed, refer to the primary literature directly — common databases include PubMed and DrugBank.