Half-life & clearance

⏳ Half-life & clearance

The best figure available for each compound, graded by how much weight it can carry. Most research peptides have never had formal pharmacokinetics done in people, so a lot of what you will find elsewhere is animal data, a measurement of something adjacent, or a number with no source at all. Rather than hide those, they are shown with the reason they are weak attached — you will meet them anyway, and knowing why a number is shaky is more use than not seeing it. Nothing here is estimated or carried across from a similar compound, and every citation was opened and checked to confirm it is the paper it claims to be.

18 human 4 animal only 1 indirect 1 disputed 9 unverified 28 not established of 61 compounds

Clearance estimator

Compound or half-life (h) Dose (any unit) Hours since dose

Reference

Compound	Half-life	Route	Evidence
AICAR	~1.4 h J Clin Pharmacol 1991, PMID 2037706 · source “the terminal elimination phase had a harmonic mean t1/2 beta of 1.4 hours” Healthy men, IV and oral 10–100 mg/kg, placebo-controlled. Biphasic decline; clearance 2.5 L/hr/kg, Vss 1.6 L/kg, not protein bound, only ~8% excreted renally as intact drug. The IV value is the one modelled — no oral half-life was established, so any oral schedule circulating online is extrapolated from these numbers rather than measured.	Intravenous	human data
Cagrilintide	159–195 h (~6.6–8.1 days) Phase 1b trial, PMID 33894838 · source “Cagrilintide 0·16–4·5 mg had a half-life of 159–195 h” The model below uses the midpoint of the published range.	Subcutaneous	human data
CJC-1295	5.8–8.1 days (DAC form) Teichman et al., JCEM 2006, PMID 16352683 · source “The estimated half-life of CJC-1295 was 5.8-8.1 d” Applies to CJC-1295 WITH DAC. The no-DAC form (Mod GRF 1-29) is a different molecule with no verified published half-life — do not apply this figure to it.	Subcutaneous / IV	human data
GHK-Cu	~0.5–1 hour (plasma) Pickart et al., Biomed Res Int 2014, PMC4180391 · source “GHK has a half-life of about 0.5 to 1 hour in plasma” Stated in a peer-reviewed review by the principal GHK investigator rather than in a dedicated pharmacokinetic study. Widely circulated figures of "~4 minutes" are contradicted by this source — roughly tenfold too short.	Plasma	human data
GHRP-6	2.96 ± 1.12 h terminal (0.14 h distribution) Eur J Pharm Sci 2013, PMID 23099431 (via PEPlife 3154/3155) · source “0.14±0.03 (t1/2α) hours; 2.96±1.12 (t1/2β) hours — intravenous bolus administration in 9 healthy male subjects.” Two-phase kinetics. The model uses the terminal (beta) phase, which is what governs clearance.	Intravenous bolus	human data
Ipamorelin	~2 hours (terminal) Gobburu et al., Pharm Res 1999, PMID 10496658 · source “The PK parameters showed dose-proportionality, with a short terminal half-life of 2 hours, a clearance of 0.078 L/h/kg and a volume of distribution at steady-state of 0.22 L/kg.”	Intravenous	human data
Kisspeptin	27.6 ± 1.1 min (kisspeptin-54) Dhillo et al., JCEM 2005, PMID 16174713 · source “the plasma half-life of kisspeptin-54 was calculated to be 27.6 +/- 1.1 min” Isoform-specific. Kisspeptin-10 is a different, shorter-acting peptide; the paper commonly cited for its half-life reports LH pulse data and no half-life value.	Intravenous	human data
Melanotan I	~15 hours FDA label — SCENESSE (afamelanotide) · source “Apparent half-life approximately 15 hours.” Reflects the controlled-release implant, not a bolus injection.	Subcutaneous implant	human data
Mounjaro	~5 days FDA label — MOUNJARO (DailyMed) · source “The apparent population mean clearance of tirzepatide is 0.061 L/h with an elimination half-life of approximately 5 days, enabling once-weekly dosing.” Mounjaro is the brand name for tirzepatide — same molecule, same value.	Subcutaneous	human data
PT-141	2.7 h (range 1.9–4.0) FDA label — VYLEESI (bremelanotide) · source “The half-life of bremelanotide is 2.7 hours (range 1.9 to 4.0 hours).”	Subcutaneous	human data
Retatrutide	~6 days Phase 1b trial, PMID 36354040 · source “The pharmacokinetics of LY3437943 were dose proportional and its half-life was approximately 6 days.”	Subcutaneous	human data
Semaglutide	~1 week FDA label — OZEMPIC (DailyMed) · source “With an elimination half-life of approximately 1 week, semaglutide will be present in the circulation for about 5 weeks after the last dose.”	Subcutaneous	human data
Tesamorelin	8 min (SV) / 11 min (WR) FDA label — EGRIFTA SV (DailyMed) · source “Mean terminal half-life 8 minutes (EGRIFTA SV 1.4 mg); 11 minutes (EGRIFTA WR 1.28 mg), in healthy subjects.” Two formulations differ; the model uses the 8-minute EGRIFTA SV value, quoted above from the current DailyMed label. Note that the peptidejournal.org chart cites 26–38 minutes, also attributed to an FDA label — most likely the older original EGRIFTA formulation rather than SV/WR. If you are reading a third-party chart, check which formulation it means.	Subcutaneous	human data
Thymosin Alpha-1	< 3 hours Int J Clin Pharmacol Ther 1999, PMID 10027483 · source “the short elimination half-life of less than 3 hours” The source states an upper bound, not a point value; the model uses 3 h as that bound.	Subcutaneous	human data
Thymosin Beta-4 (TB4)	0.5–2.08 h (dose-dependent) First-in-human recombinant Tβ4, PMC8419156 · source “the Tmax was from 3 to 15 minutes, and t1/2 was from 0.5 to 2.08 hours” This is full-length recombinant thymosin β4. TB-500 is a shorter fragment and is NOT covered by this figure.	Intravenous	human data
Tirzepatide	~5 days FDA label — MOUNJARO (DailyMed) · source “The apparent population mean clearance of tirzepatide is 0.061 L/h with an elimination half-life of approximately 5 days, enabling once-weekly dosing.”	Subcutaneous	human data
TRT (Testosterone)	~8 days (cypionate ester) FDA label — Testosterone Cypionate (DailyMed) · source “The half-life of testosterone cypionate when injected intramuscularly is approximately eight days.” Ester-specific. The enanthate label gives no ester half-life — its "10 to 100 minutes" figure describes FREE testosterone once released, not the depot, and must not be read as a clearance time for the injection.	Intramuscular	human data
VIP	~1 minute Domschke et al., Gut 1978, PMID 730072 · source “plasma VIP levels fell strikingly by first order kinetics with an average disappearance half-time of one minute”	Intravenous infusion	human data
BPC-157	15.2 min (rat) · 5.27 min (dog) Front Pharmacol 2022, PMC9794587 · source “the average elimination half-life (t1/2) was 15.2 min [rat]; the t1/2 and AUC0–t of BPC157 in dogs were 5.27 min” ANIMAL DATA ONLY. No human pharmacokinetic study has been published. The model uses the rat IV value and should be read as illustrative, not predictive of human clearance.	Intravenous	animal only
Dihexa	12.68 days IV · 8.83 days IP (rat) McCoy et al., J Pharmacol Exp Ther 2013, PMID 23055539 / PMC3533412 · source “Dihexa exhibited a long half-life (t1/2) of 12.68 days following i.v. administration and similarly when delivered intraperitoneally [8.83 ± 2.41 days].” RAT data; no human pharmacokinetics published. Note the unit: circulating figures of "12 hours" are roughly 25× too short — the measured value is 12.68 DAYS.	Intravenous / intraperitoneal	animal only
DSIP	4.0 min dog · 2.9 min monkey · 2.0 min rat Neuroendocrinology 1984, PMID 6379493 · source “a mean half-life of 4.0 +/- 0.7 min in the dogs… a rapid in vivo clearance of DSIP from plasma with a half-life of 2.9 and 2.0 +/- 0.54 min, respectively [monkey, rats].” ANIMAL DATA ONLY across three species; no human value found. The model uses the dog figure.	Intravenous	animal only
Gonadorelin	2.66 min α / 12.16 min β (rat) Regul Pept 1991, PMID 1882091 (via PEPlife 2921) · source “2.66 (t1/2 alpha) minutes; 12.16 (t1/2 beta) minutes — dose IV injected, rat plasma.” RAT plasma, not human. A separate database entry citing PMID 12083977 was discarded on checking: that paper is about depot leuprorelin, a different long-acting analogue.	Intravenous	animal only
Hexarelin	~50 min (from the GH response) Eur J Clin Pharmacol 1994, PMID 7957536 (via PEPlife 2461) · source “50 minutes — twelve adult male volunteers.” Read this carefully: the cited paper is a growth-hormone dose-response study, so this figure tracks how long the GH response takes to subside, NOT measured plasma clearance of hexarelin itself. Animal work gives roughly 61–76 min (rat IV) and 25–120 min (dog IV).	Intravenous	indirect measure
Oxytocin	Disputed — 3.2–4.8 min vs 10.3 min Fabian et al., J Physiol 1969 (PMID 5824107) · JCEM 1980 (PMID 7354123) · source “"The median half-life of oxytocin after a single injection of 2 u. was 3.2 min… increased significantly to 4.8 min when the hormone was infused" (1969) versus "a mean calculated half-life of 10.3 +/- 1.6 min (range, 5.3-17.3 min)" (1980).” Two credible human studies disagree by roughly threefold. No single value is offered for modelling — pick one deliberately if you need to.	Intravenous	sources disagree
AOD-9604	~4 minutes (widely cited, unverified) No traceable primary source · source “Circulated as ~4 min serum half-life.” CITATION DOES NOT CHECK OUT. Usually credited to PMID 11146367 (linked), which is a chronic oral-dosing study in obese Zucker rats measuring body weight and lipolysis — it contains no pharmacokinetic data at all.	Injection	unverified
GHRP-2	~25–30 minutes peptidejournal.org chart — labelled "Preclinical est." · source “GHRP-2 — ~25-30 minutes, SC, 2-3x daily. Data source: Preclinical est.” The chart itself marks this an estimate rather than a measured human value. PeptIQ separately lists ~30 minutes.	Subcutaneous	unverified
KPV	Not well characterised peptidejournal.org chart — labelled "Limited data" · source “KPV — not well characterized, SC/topical, dosing varies, steady state unknown. Data source: Limited data.” The chart declines to give a number, which matches what we found: no primary pharmacokinetic study exists. PeptIQ lists "~1 hour (estimated)".	SubQ / topical	unverified
LL-37	Short — minutes to hours peptidejournal.org chart — labelled "Limited data" · source “LL-37 — short (minutes to hours), topical/local. Data source: Limited data.” No numeric value anywhere we could verify. PEPlife does list LL-37 figures but credits them to PMID 5092290, which is a 1971 Nursing Times article — discarded.	Topical / local	unverified
MK-677	~24 hours (widely cited, unverified) No traceable primary source · source “Circulated as ~24 h, consistent with the once-daily oral dosing used in trials.” CITATION DOES NOT CHECK OUT, AND SOURCES DISAGREE. The ~24 h figure is usually credited to PMID 8707253, which is an unrelated hepatitis C DNA-vaccine paper; the real Chapman 1996 study (PMID 8954023, linked) reports GH and IGF-1 pulsatility and states no half-life. Separately, the peptidejournal.org chart gives 4–6 hours labelled "Clinical PK" — a four- to six-fold disagreement with the number everyone quotes. Neither is traceable to a primary document we could open.	Oral	unverified
Selank	Minutes (intranasal) peptidejournal.org chart — labelled "Clinical est. (Russia)" · source “Selank — minutes (intranasal), 2-3x daily. Data source: Clinical est. (Russia).” Same caveat as Semax. Note that pep-pedia lists identical peak/half-life/clearance numbers for both compounds, which suggests a template rather than a measurement.	Intranasal	unverified
Semax	Minutes (intranasal) peptidejournal.org chart — labelled "Clinical est. (Russia)" · source “Semax — minutes (intranasal), 2-3x daily. Data source: Clinical est. (Russia).” No number precise enough to model. The underlying Russian clinical work is not indexed in a form we could open and verify.	Intranasal	unverified
Sermorelin	11–12 minutes peptidejournal.org chart — labelled "Clinical PK" · source “Sermorelin — 11-12 minutes, SC/IV, daily (bedtime), steady state ~1 hour. Data source: Clinical PK.” Secondary source. The original GEREF label would settle it, but that product was discontinued in 2008 and is no longer on DailyMed, so no primary document could be opened.	Subcutaneous / IV	unverified
TB-500	Not established — serum detectable ~40 min (mouse) Mora et al., Int J Immunopharmacol 1997, PMID 9226473 · source “serum thymosin beta-4 detectable starting 2 min after injection and lasting for 40 min; the paper states that studies on the pharmacokinetics of Tβ4 in human and other mammals have not been reported.” No half-life has been calculated for TB-500 in any species. The commonly quoted "2.5 hours" is credited to this paper, which contains no such figure — it reports a detection window in mice. TB-500 is also a 7-amino-acid fragment, so the full-length thymosin β4 human value does not transfer to it.	Intraperitoneal	unverified

28 compounds have no published half-life we could verify — no pharmacokinetic study has been done, in people or animals, that we could open and check: 5-Amino-1MQ, ACE-031, Adamax, Adipotide, AHK-Cu, ARA-290, Cartalax, Cerebrolysin, Epithalon, Follistatin-344, GDF-8 (Myostatin), GLOW, HCG, Humanin, IGF-1 DES, IGF-1 LR3, KLOW, Melanotan II, MGF, MOTS-c, NAD+, NMN, PE-22-28, PEG-MGF, SLU-PP-332, SS-31, Tesofensine, Thymalin.

Figures that did not survive checking

These numbers circulate widely. We traced each to its usual citation, opened it, and found the citation does not support the figure. Where the compound is in the table above it now appears there too, marked unverified with this caveat attached — so you get the number people quote, and the reason not to lean on it.

MK-677

The "~24 hour" figure is usually cited to PMID 8707253, which is an unrelated hepatitis C DNA-vaccine paper. The actual Chapman 1996 study (PMID 8954023) reports GH and IGF-1 pulsatility only, with no half-life.

AOD-9604

The "~4 minute" figure is usually cited to PMID 11146367, which is a chronic-dosing study in obese Zucker rats containing no pharmacokinetic data at all.

Kisspeptin-10

The "~4 minute" figure is usually cited to PMID 21632807, which reports LH pulse-frequency effects and states no half-life.

CJC-1295 without DAC (Mod GRF 1-29)

The "~30 minute" figure traces only to vendor pages; no peer-reviewed or regulatory source states it.

GHK-Cu "~4 minutes"

Credited to Pickart, whose paper actually states about 0.5 to 1 hour in plasma — roughly ten times longer. The correct figure is in the table above.

Dihexa "12 hours"

The measured value from the same research group is 12.68 DAYS by IV in rats — about 25 times longer. A unit confusion, not a small discrepancy.

Melanotan II "1 hour"

Credited to "Dorr et al. 1996, J Natl Cancer Inst 88(17):1196-1201". That citation does not exist: every article in that issue is on an unrelated cancer topic. The real Dorr 1996 melanotan-II paper (Life Sciences, PMID 8637402) reports no pharmacokinetic value at all.

MOTS-c "4 hours"

Credited to Lee et al. 2015 (PMID 25738459), whose full text contains no mention of half-life — only a dosing protocol.

GHRP-6 "20 minutes"

Credited to Bowers et al. 1991 (PMID 2004615), a rat mechanism study with no pharmacokinetic data. A real human value does exist and is in the table above.

Half-life describes how fast a compound leaves the blood. It is not a duration of effect — some compounds act long after they are cleared, and others are cleared while still bound at their target. Educational reference only; nothing here is a dosing instruction.