Half-Life Reference Chart
A static, at-a-glance reference for approximate half-lives of common peptides and the dosing frequency each implies. Half-life is roughly the time for blood levels to fall by half; a short half-life usually means more frequent dosing, a long one allows less frequent dosing. For the concepts behind this table, see Half-Life & Pharmacokinetics.
Read this first
These values are approximate and many are drawn from limited or animal data. Where human pharmacokinetics are poorly characterized, the cell says “approx” or “not well established.” Half-life is only one input into dosing — receptor kinetics, the duration of the downstream effect (e.g. a GH pulse), and clinical context all matter. This is educational, not a dosing recommendation.
Reference table
| Peptide | Approx half-life | Typical dosing frequency | Notes |
|---|---|---|---|
| BPC-157 | ~minutes (approx; animal data) | 1–2× daily | Human PK not well established; short systemic half-life but locally acting; route-dependent |
| TB-500 | Not well established (approx hours, route-dependent) | ~1–2× weekly | Full Tβ4 reported ~hours; community protocols use a weekly “loading/maintenance” pattern |
| CJC-1295 without DAC (Mod GRF 1-29) | ~30 minutes (approx) | Multiple times daily | Very short; designed to mimic a single GH pulse; often paired with Ipamorelin |
| CJC-1295 with DAC | ~6–8 days | ~1–2× weekly | DAC binds albumin for a slow-release depot; sustained (less pulsatile) GH/IGF-1 rise |
| Ipamorelin | ~2 hours | 1–3× daily | GH peak ~0.67 h after dosing then rapid decline; injectable (destroyed in gut) |
| MK-677 | ~24 hours | Once daily | Orally active non-peptide ghrelin mimetic; sustained 24-h GH/IGF-1 elevation |
| Sermorelin | ~10–20 minutes | Once daily (usually bedtime) | Very short; GHRH analog; often timed to nocturnal GH pulse |
| Tesamorelin | ~11 minutes (SC, healthy subjects) | Once daily | Short half-life but once-daily per FDA labeling (Egrifta) |
| Semaglutide | ~7 days (~160 h) | Once weekly | GLP-1 analog; fatty-diacid albumin binding enables weekly dosing |
| Tirzepatide | ~5 days | Once weekly | Dual GIP/GLP-1 agonist; albumin-binding chain enables weekly dosing |
| Retatrutide | ~6 days | Once weekly | Investigational triple GIP/GLP-1/glucagon agonist; dose-proportional PK |
| PT-141 | ~2.7 h (range ~1.9–4.0 h) | On demand | Short half-life fits its as-needed use pattern |
| SS-31 | ~ a few hours (SC; approx) | Once daily | Mitochondria-targeting tetrapeptide (elamipretide); indication-dependent |
| Thymosin Alpha-1 | ~2 hours | ~2× weekly | Approved-abroad regimen (thymalfasin) is 1.6 mg twice weekly |
| Kisspeptin | ~4 min (Kp-10); Kp-54 ~28 min | Infusion (trials) | Very short; trials use IV infusion or the longer Kp-54 fragment |
| Epitalon | Very short (~minutes; approx) | Daily in short courses | Rapidly hydrolyzed; human PK not well characterized; typically dosed in 10–20 day courses |
How to read it
- Short half-life (minutes to a few hours) — e.g. Sermorelin, Tesamorelin, no-DAC CJC-1295, Ipamorelin, PT-141. These clear quickly, so they are dosed daily, several times daily, or on demand. A short half-life is often intentional for GH secretagogues, which aim to mimic the body’s natural brief pulses rather than a constant elevation.
- Long half-life (days) — e.g. CJC-1295 with DAC, Semaglutide, Tirzepatide, Retatrutide. Albumin binding (or, for the GLP-1 class, a fatty-acid chain) extends these to days, enabling once-weekly dosing.
- Poorly characterized — e.g. BPC-157, TB-500, Epitalon. Systemic half-life is uncertain in humans; dosing frequency in these cases comes from community/empirical practice, not robust PK studies.
For side-by-side comparisons across more attributes, see Comparison Tables and Stacks & Comparisons.
Educational information only — not medical advice. See Disclaimer.