Peptide Half-Life Reference Chart
Overview
Half-life (t½) is the time required for the plasma concentration of a compound to decrease by 50%. It is one of the most practically relevant pharmacokinetic parameters for research study design, as it determines appropriate dosing intervals, washout periods, and the time required to reach steady-state concentrations.
Data quality note: Half-life data for many research peptides is derived from animal studies, inference from dosing intervals used in efficacy studies, or limited human PK characterization. Where human PK data exists (e.g., tesamorelin, semaglutide), it is noted. All values should be treated as approximations unless otherwise indicated.
Key practical rules for using half-life data:
- Steady state: Approximately 4–5 half-lives are required to reach steady-state plasma concentrations with repeated dosing
- Washout: Approximately 4–5 half-lives are required to eliminate ~97% of a compound from circulation
- Accumulation: Compounds with long half-lives (days to weeks) will accumulate with daily dosing — important for study design
- Pharmacodynamic vs. pharmacokinetic half-life: Biological effects may persist longer than plasma half-life predicts (e.g., melanin production after MT-II clearance)
Repair Peptides
| Compound | Route | Estimated Half-Life | Data Source | Profile |
|---|---|---|---|---|
| BPC-157 | IP / SC | ~4 hours | Inferred from rodent dosing intervals | View → |
| TB-500 | SC / IP | ~1–2 days | Estimated from preclinical dosing protocols | — |
| Thymosin Beta-4 | IV / IP | ~30–60 min (plasma); hours (tissue) | Limited PK data; plasma clearance rapid | — |
| GHK-Cu | SC / Topical | ~1–2 hours (systemic) | Small tripeptide; rapid renal clearance | — |
GH Axis Peptides
| Compound | Route | Estimated Half-Life | Data Source | Profile |
|---|---|---|---|---|
| Tesamorelin | SC | ~26 minutes (plasma) | Human PK from Phase III trials | View → |
| CJC-1295 (with DAC) | SC | ~6–8 days | Human PK data; DAC extends half-life dramatically | — |
| CJC-1295 (no DAC) | SC | ~30 minutes | Without DAC modification; short-acting | — |
| Ipamorelin | IV / SC | ~2 hours | Rodent and limited human data | — |
| IGF-1 LR3 | SC / IV | ~20–30 hours | Long-acting due to reduced IGFBP binding | — |
| AOD-9604 | SC / Oral | ~30 minutes (SC) | Human PK data available | — |
| Fragment 176-191 | SC | ~30 minutes | Similar to AOD-9604; small fragment | — |
| MOTS-c | IV / IP | ~2–4 hours | Estimated from rodent dosing studies | — |
Metabolic Compounds
| Compound | Route | Estimated Half-Life | Data Source | Profile |
|---|---|---|---|---|
| Semaglutide | SC (weekly) | ~7 days | Human PK from Phase III FDA-approval trials | — |
| Tirzepatide | SC (weekly) | ~5 days | Human PK from FDA-approval data | — |
| Retatrutide | SC (weekly) | ~6 days | Phase II human PK data | — |
| Tesofensine | Oral | ~220 hours (~9 days) | Human PK from TIPO-1 trial data | — |
CNS & Nootropic Peptides
| Compound | Route | Estimated Half-Life | Data Source | Profile |
|---|---|---|---|---|
| Selank | IN / SC | ~2 minutes (plasma); longer CNS | Russian clinical research; rapid plasma degradation | — |
| Semax | IN / SC | ~15–20 minutes (plasma) | Russian PK studies; nasal route extends CNS access | — |
| DSIP | IV / SC | ~30–50 minutes | Human and animal PK data; rapid enzymatic degradation | — |
| Epitalon | SC / IV | ~30 minutes | Tetrapeptide; rapid clearance; biological effects persist | — |
Melanocortin Peptides
| Compound | Route | Estimated Half-Life | Data Source | Profile |
|---|---|---|---|---|
| Melanotan II | SC | ~1–2 hours (plasma) | Human Phase I/II data; cyclic structure improves stability | — |
| PT-141 (Bremelanotide) | SC / Intranasal | ~2.7 hours (SC) | FDA approval PK data | — |
Interpreting Half-Life Data
Why Half-Life ≠ Duration of Effect
Plasma half-life and biological effect duration often diverge significantly for peptides. Several mechanisms create this disconnect:
- Receptor occupancy kinetics: A brief pulse of receptor activation (e.g., GH secretion from ipamorelin) can produce downstream effects lasting hours after the peptide itself has cleared
- Downstream signaling cascades: Once activated, signaling pathways (e.g., ILK/Akt from Thymosin Beta-4) can continue independently of the stimulus
- Downstream biosynthesis: Melanin production triggered by Melanotan II persists for days after peptide clearance; collagen synthesis triggered by GHK-Cu similarly outlasts plasma concentration
- Tissue vs. plasma half-life: Tissue concentrations often exceed plasma concentrations and persist longer, especially for peptides that bind tissue receptors or matrix proteins
Route of Administration Effects
Half-life can vary substantially by route. Intravenous administration produces the highest initial peak concentration and fastest clearance. Subcutaneous and intramuscular routes produce delayed absorption (slower Tmax) and often slightly longer effective half-lives due to the sustained release from the injection depot. Intranasal routes can provide rapid CNS access that is disproportionate to plasma concentrations.
Using the Calculator
For research dose volume calculations based on vial concentration and target dose, use the Alpha Tides Peptide Calculator. For dosage range data from published literature, see the Peptide Dosage Reference Chart.
References
- Falutz J, Mamputu JC, Potvin D, et al. "Effects of tesamorelin (TH9507) in HIV-infected patients with abdominal fat accumulation." J Acquir Immune Defic Syndr. 2010;53(3):311–322. PMID: 20101189. PubMed →
- Astrup A, Madsbad S, Breum L, et al. "Effect of tesofensine on bodyweight loss." Lancet. 2008;372(9653):1906–1913. PMID: 18950853. PubMed →
- Lau J, Bloch P, Schäffer L, et al. "Discovery of the once-weekly glucagon-like peptide-1 (GLP-1) analogue semaglutide." J Med Chem. 2015;58(18):7370–7380. PMID: 26308095. PubMed →
- Wessells H, Levine N, Hadley ME, Dorr R, Hruby V. "Melanocortin receptor agonists, penile erection, and sexual motivation." Int J Impot Res. 2000;12 Suppl 4:S74–79. PMID: 10845756. PubMed →
- Sikiric P, Seiwerth S, Rucman R, et al. "Stable gastric pentadecapeptide BPC 157: novel therapy in gastrointestinal tract." Curr Pharm Des. 2011;17(16):1612–1632. PMID: 21548867. PubMed →