This chart is built the same way as this site's dosage chart: nothing is estimated, every figure is read out of a named source on a named date, and where the number does not exist the row says so rather than filling the cell.
Doing it that way produces a finding that the half-life charts circulating in this market cannot show, because showing it would empty most of their columns.
Most of the famous peptide half-life numbers were not measured in humans. They are real figures, correctly copied, from mice, dogs, rats and liver microsomes — printed in the same column as label figures from approved drugs, with nothing to tell a reader which is which.
What the word means here
Throughout this page, half-life means the pharmacokinetic half-life: the time taken for the concentration of the compound in blood plasma to fall by half after administration.
It is not a shelf-life. A reconstituted vial's usable life is a stability question decided by temperature, light and preservative, and is covered on peptide storage. The two numbers have no relationship at all — tesamorelin is cleared from the blood in eight minutes and its vials are stable for weeks.
The chart
Columns: the figure as its source states it, the source, and the date that source was read or published. Read the "measured in" column before quoting any row.
Figures from an FDA-approved label
| Compound | Half-life as stated | Measured in | Source |
|---|---|---|---|
| Semaglutide | approximately 1 week | Patients with type 2 diabetes | Ozempic label, elimination section, effective 30 Jan 2026 |
| Tirzepatide | approximately 5 days | Population estimate | Mounjaro label, elimination section, effective 29 Jul 2026 |
| Afamelanotide (Melanotan-1) | approximately 15 hours, apparent | Subcutaneous controlled-release implant | Scenesse label, effective 11 May 2026 |
| Bremelanotide (PT-141) | 2.7 hours (range 1.9–4.0), terminal | Single subcutaneous dose | Vyleesi label, effective 13 Nov 2025 |
| Liraglutide | 13 hours | Single subcutaneous dose | Liraglutide label, effective 13 Nov 2025 |
| Setmelanotide | approximately 11 hours, effective | — | Imcivree label, effective 1 Apr 2026 |
| Oxytocin | 1 to 6 minutes, decreased in late pregnancy and during lactation | Plasma | Pitocin label, effective 6 May 2026 |
| Tesamorelin | 8 minutes, mean elimination | Healthy subjects, single 1.4 mg subcutaneous dose | Egrifta SV label, effective 29 Jul 2026 |
For reference, the same liraglutide label states that native GLP-1(7 to 37) has a half-life of 1.5 to 2 minutes, degraded by dipeptidyl peptidase 4 and neutral endopeptidases.
Figures from a published human study
| Compound | Half-life as stated | Measured in | Source |
|---|---|---|---|
| CJC-1295 with DAC | 5.8 to 8.1 days, estimated | Healthy subjects aged 21–61, two randomised placebo-controlled ascending-dose trials | Teichman et al., J Clin Endocrinol Metab, 2006 (PMID 16352683) |
| Ipamorelin | 2 hours, terminal | Eight healthy male subjects at each of five 15-minute infusion rates, 4.21–140.45 nmol/kg | Gobburu et al., 1999 (PMID 10496658) |
| GHRP-6 | 7.6 ± 1.9 minutes distribution, 2.5 ± 1.1 hours elimination | Nine male healthy volunteers, single intravenous boluses of 100, 200 and 400 μg/kg, validated LC-MS with internal standard | Cabrales et al., Eur J Pharm Sci, 2013 (PMID 23099431) |
| Cagrilintide | 159 to 195 hours across doses of 0.16–4.5 mg | Phase 1b, participants with overweight or obesity, given with semaglutide 2.4 mg | Enebo et al., Lancet, 2021 (PMID 33894838) |
| Retatrutide | approximately 6 days; pharmacokinetics dose-proportional | Phase 1b, patients with type 2 diabetes, 12 weeks of weekly dosing | Urva et al., Lancet, 2022 (PMID 36354040) |
| Gonadorelin | no half-life stated; plasma returned to baseline in under 60 minutes intravenously and over 120 minutes subcutaneously | 14 hypogonadotropic patients, 5 μg bolus by each route | Handelsman et al., J Clin Endocrinol Metab, 1984 (PMID 6384253) |
These six are the whole of it. GHRP-6 and gonadorelin were added on 21 September 2026 while building their dosage records, and cagrilintide and retatrutide on 22 September 2026 — which is how this chart is meant to grow.
The last two correct this page's first version, which listed both among compounds whose half-life is implied only by a weekly schedule. Both figures sit in the abstracts of the manufacturers' own phase 1b papers; the search that missed them looked in registered protocols, where they are not. Both trials are sponsor-run (Novo Nordisk and Eli Lilly respectively), and the cagrilintide figure was measured with semaglutide given alongside it — its authors report semaglutide's half-life in the same participants as 145 to 165 hours.
Two cautions attach to the new rows. The GHRP-6 figures are intravenous, and the same paper reports atypical concentration spikes during the elimination phase in four of its nine subjects, so the 2.5-hour elimination figure carries a real limitation its authors stated rather than smoothed. The gonadorelin row is included precisely because it is not a half-life: the human record for that compound gives a return-to-baseline time by route, and printing it in a half-life column without the distinction would be the error this page exists to expose. Its dosage record is at gonadorelin, and the half-life question there is secondary to the dosing interval.
Every other non-approved compound in this catalogue falls into one of the three categories below.
Figures that are quoted as human and are not
| Compound | Figure in circulation | What it actually measured | Source |
|---|---|---|---|
| Kisspeptin (KP-54) | approximately 32 minutes | Male mice | d'Anglemont de Tassigny et al., PLoS One, 2017 (PMID 28464043) |
| Kisspeptin (KP-10) | approximately 4 minutes | Male mice, same study | as above |
| DSIP | 4.0 ± 0.7 minutes | Four anaesthetised dogs given 1 or 2 mg intravenously | Kato et al., Neuroendocrinology, 1984 (PMID 6379493) |
The DSIP paper is worth reading past the headline figure: alongside the dog result it reports 2.9 minutes in a monkey and 2.0 ± 0.54 minutes in rats. Three species, three numbers, none of them ours, and the number that travelled is the one from the largest group.
The kisspeptin case is the more instructive of the two, because this site does hold a human kisspeptin dose record — the infusion studies behind that compound's dosage page are in people. The half-life figure circulating beside those doses is nonetheless from mice. A compound having human evidence does not mean that every number attached to it is human, and nothing on the face of a chart reveals which is which.
Figures that exist only in vitro, for a stated reason
For TB-500, GHRP-2 and hexarelin, the published metabolic work was done in human liver microsomes and S9 fraction rather than in volunteers.
GHRP-6 was named in that same paper, and it is the exception that shows the limit of the reasoning. A separate group at the Center for Genetic Engineering and Biotechnology in Havana ran the human study anyway, in nine male volunteers, and its figures are in the human-study table above. Corrected here on 21 September 2026 while building the GHRP-6 dosage record: a stated reason for an absence is strong evidence about the laboratory that stated it and weak evidence about anywhere else. This page had generalised it to four compounds, and one of them had the study.
The reason is not left to inference. A 2015 paper from the Ghent University doping control laboratory (Esposito et al., J Pept Sci 2015;21(1):1–9, PMID 25469748), which evaluated those in vitro models for exactly these compounds, states that detection of misuse is difficult because of short plasma half-life and rapid elimination, that investigating metabolism improves detectability, and that pharmacokinetic studies with human volunteers are often not allowed because of ethical constraints, so alternative models are needed.
That sentence explains a great deal about this market's charts. For a large part of the research-peptide catalogue, the human number does not exist because the study is not permitted — not because nobody has got round to it. A chart that prints a confident figure for TB-500 is printing something other than a measurement.
Compounds with no half-life figure in any of the three source classes
Checked on 20 September 2026 against current FDA labels, registered protocols and indexed study abstracts, and not found:
BPC-157 · MOTS-c · epitalon · GHK-Cu · IGF-1 LR3 · AOD-9604 · KPV · 5-amino-1MQ · SLU-PP-332 · semax · selank · noopept · glutathione · NAD+ · melanotan II · thymosin alpha 1 · VIP (aviptadil) · adipotide · tesofensine · KLOW · the Wolverine stack · Lipo-C
Two qualifications on that list, both of which matter.
First, it is a bounded absence. It means those three source classes were opened and the figure was not in them. A number may exist in the full text of a paper whose abstract does not carry it, or in a regulatory dossier that is not public. This page distinguishes that from the TB-500 case above, where the absence has a published explanation, because a documented reason is stronger evidence than a failed search.
Second, for survodutide the absence is a fact about where its numbers are published rather than about whether they were measured. It is in an active trial programme with once-weekly subcutaneous dosing, and its discovery paper describes a C18 fatty acid added "as a half-life extending principle to support once-weekly dosing in humans" — a design intent, not a measured figure. Its dose record is on survodutide. Retatrutide and cagrilintide sat in this paragraph until 22 September 2026; both turned out to have a measured human figure in a published abstract, and have moved to the table above.
The blends — KLOW, the Wolverine stack and Lipo-C — cannot have a half-life in the singular at all. They contain several molecules with different clearance, so a single figure for the blend is not a quantity that exists, whatever a seller's page prints.
The spread, which is the number worth carrying away
Among peptides with an FDA label — the strongest evidence class on this chart — the range is:
| Compound | Half-life | Ratio to the shortest | |
|---|---|---|---|
| Shortest | Tesamorelin | 8 minutes | 1× |
| Oxytocin | 1–6 minutes | — | |
| Bremelanotide | 2.7 hours | ~20× | |
| Liraglutide | 13 hours | ~98× | |
| Afamelanotide | 15 hours | ~113× | |
| Tirzepatide | ~5 days | ~900× | |
| Longest | Semaglutide | ~1 week | ~1,260× |
Between two FDA-labelled peptides, both injected under the skin, both supplied in a small glass vial, the time they remain in circulation differs by a factor of about 1,260.
And against the hormone the largest class on this chart is modelled on, the engineering is larger still. Native GLP-1 is cleared with a half-life of 1.5 to 2 minutes. Semaglutide's is approximately one week. That is a roughly 6,700-fold extension, and both labels state plainly how it was achieved: the Ozempic label attributes it to albumin binding, which reduces renal clearance and protects the molecule from metabolic degradation, and the Mounjaro label says tirzepatide contains a C20 fatty diacid that binds albumin and prolongs the half-life.
The practical reading is that peptide half-lives do not cluster. Nothing about a compound being a peptide, or being sold in the same catalogue as another peptide, predicts its half-life within three orders of magnitude. The inversion is sharpest in one pair: the approved daily drug tesamorelin has a label half-life of minutes while unapproved ipamorelin's measured figure is two hours, which our tesamorelin vs ipamorelin comparison explains.
What a half-life figure does not tell you
Three limits, each of which is visible in a row above.
It is not a dosing interval. Afamelanotide's apparent half-life is about 15 hours, and Scenesse is an implant administered every two months. The half-life describes the molecule leaving the blood; the schedule is decided by the formulation, and here the formulation is a controlled-release implant. A chart's half-life column cannot be read as a "how often" column.
It is not stability. Covered above, and it is the single most common conflation on retail pages: a short plasma half-life says nothing about how long a vial lasts in a fridge.
It is not evidence of potency or of anything working. Eight minutes is enough for tesamorelin to do what it is labelled to do. Its shorter relative sermorelin is also cleared within minutes of an intravenous dose while growth hormone stays raised for about three hours, and the sermorelin trial doses were set around that response, not around the peptide's time in the blood.
Method
Every figure on this page was read on 20 September 2026 from one of:
- the pharmacokinetics or clinical pharmacology section of the current FDA label, retrieved through openFDA and identified by its effective date;
- a published study, retrieved through PubMed and cited by PMID;
- a registered trial protocol on ClinicalTrials.gov.
No figure on this page was carried over from another chart, a vendor page or a forum. Where a compound's number came from an animal or an in vitro model, that is stated in the same cell as the number rather than in a footnote, which is the one editorial decision that separates this table from the ones it competes with.
Figures are reported as the sources state them. Nothing here is a dosing instruction, and a half-life is not a schedule.