Peptide Half-Life Chart: Research Peptides Compared (2026)

Half-life charts circulate widely across peptide vendor blogs and forums, and most of them share the same problem: the same handful of numbers get copied from site to site without anyone tracing them back to a primary source. A figure like "TB-500 half-life: 3 hours" looks precise, but if you follow it back far enough, it usually dead-ends in another blog post, not a pharmacokinetic study.

This chart takes the opposite approach. For every peptide below we either cite a real, checkable source (a PubMed-indexed study or an FDA prescribing label) or we say plainly that no reliable figure exists. That second category is large, larger than most vendor charts admit, and it is arguably the more useful information: knowing that a number is unverified is better than trusting a number that was never measured.

What "half-life" means, and what it does not

Elimination half-life is the time it takes for the concentration of a substance in blood plasma to fall by half, driven by renal filtration, enzymatic degradation, or receptor-mediated clearance. It is a pharmacokinetic measurement, not a measurement of biological effect. A peptide can clear from plasma in minutes while the downstream consequence of its brief presence, a change in gene expression, a receptor conformational shift, a signalling cascade, plays out over a much longer window.

Half-life is also route- and species-dependent. A number measured after intravenous bolus in rats does not automatically transfer to subcutaneous injection in humans, and a figure describing in vitro enzymatic stability (how fast a peptide degrades in a test tube) is not the same as an in vivo plasma clearance rate. Both distinctions matter throughout the table below, which is why we added a dedicated "Route / species" column rather than folding that information into a footnote.

The chart: elimination half-lives compared

The table below covers more than 30 peptides across five research classes: long-acting metabolic/incretin peptides, GH-axis secretagogues, healing and regenerative peptides, mitochondrial and longevity peptides, and shorter cognitive or signalling peptides. Where a figure is genuinely established in humans, we state the number and the primary source. Where it is preclinical-only, in vitro-only, or simply unverified, we say so instead of rounding to a plausible-looking figure.

Long-acting metabolic peptides: why weekly dosing works

The clearest, best-sourced cluster in the entire table is the fatty-acid-conjugated or albumin-binding incretin class. Native GLP-1 has a plasma half-life of only about 2 minutes; native human amylin (the hormone cagrilintide is engineered to mimic) clears in roughly 13 minutes. Semaglutide, tirzepatide, retatrutide, and cagrilintide extend that window to days, not through a different receptor mechanism but through molecular engineering, a fatty-acid side chain (semaglutide, tirzepatide) or a similar albumin-binding strategy, that resists renal filtration and slows enzymatic breakdown. Trial-design half-lives in the 5-8 day range are exactly what allows once-weekly dosing regimens in the clinical studies that established these figures. The mechanism is the same reason CJC-1295 with DAC (a maleimide-albumin-binding GHRH analogue) produces GH and IGF-1 elevation for 6-11 days after a single dose, versus roughly 30 minutes for CJC-1295 without DAC (more precisely, Mod-GRF 1-29), which lacks the albumin-binding moiety entirely.

Retatrutidemetabolic

First-ever triple-action weight management peptide targeting three receptors at once: GLP-1, GIP, and glucagon. Shown exceptional results in Phase 2 trials - up to 24% weight reduction. The most advanced metabolic peptide available.

Tirzepatidemetabolic

A first-in-class dual GIP and GLP-1 receptor agonist, and one of the most extensively studied compounds in modern metabolic and weight-regulation research. Supplied as a lyophilised research peptide with a per-batch certificate of analysis, for laboratory and in-vitro use only.

Cagrilintidemetabolic

Long-acting amylin analog studied for once-weekly satiety and appetite control. Phase 3 REDEFINE trials complete, NDA filed with FDA December 2025. A mechanism distinct from GLP-1 agonists.

GH-axis secretagogues: minutes versus days, depending on formulation

Growth-hormone secretagogues span the widest range in this entire chart, and the spread is mostly about formulation, not target biology. Sermorelin clears in roughly 11-12 minutes. Ipamorelin, a selective ghrelin-receptor mimetic studied in a formal human dose-escalation trial, has a plasma half-life of about 2 hours (PMID 10496658), one of the more solidly documented figures in the GH-secretagogue class. Tesamorelin's reported range (roughly 11-38 minutes) varies by source and analysis method, which is why the table presents it as a range rather than a single rounded figure. GHRP-6 was studied in nine healthy volunteers with a distribution half-life around 7.6 minutes and an elimination half-life around 2.5 hours, illustrating the difference between how fast a peptide initially redistributes out of the bloodstream versus how long it ultimately takes to clear.

A frequent chart error worth calling out directly: "CJC-1295" is often used as if it were one substance with one half-life. It is not. The DAC-bearing version behaves like a multi-day peptide through covalent albumin binding; the no-DAC version (properly Mod-GRF 1-29) behaves like a 30-minute peptide, similar to sermorelin. Lumping both under a single number is a common and consequential mistake in vendor charts.

One deliberate omission: MK-677 (ibutamoren), an orally active GH secretagogue frequently discussed alongside this class, is not a peptide. It is a non-peptide small molecule, and including it in a peptide half-life chart without that label is a classification error we chose not to repeat here.

Sermorelingrowth

GHRH(1-29) analog for physiological growth hormone stimulation research

CJC-1295 (No DAC)growth

CJC-1295 without DAC (Mod GRF 1-29) is a short-acting GHRH(1-29) analog for GH/IGF-1 research. Research-grade lyophilized powder, specified purity >=99% (HPLC). Laboratory use only.

Ipamorelingrowth

Highly selective growth hormone releaser that triggers natural GH pulses without raising cortisol or prolactin. Clean GH stimulation with minimal side effects - the most targeted growth hormone peptide available.

Tesamorelingrowth

Modified GHRH analog for lipodystrophy and metabolic liver research

Healing and regenerative peptides: the short-half-life myth

This is the class where the "short plasma half-life equals short effect" misconception does the most damage to public understanding. BPC-157's only verified pharmacokinetic data comes from a single rat-and-dog study: about 15.2 minutes after a single IV dose in rats, and 5.3-29.7 minutes across intramuscular doses in rats and dogs (PMID 36588717). No published human pharmacokinetic study of BPC-157 exists, despite how often "human half-life" numbers for it circulate online. Pentadeca Arginate (PDA), marketed as a distinct, improved peptide, is chemically the same 15-amino-acid BPC-157 sequence with an arginine salt in place of acetate; its half-life claims are inherited from the same rat/dog data, not independently measured.

TB-500 (Thymosin beta-4) and GHK-Cu fare worse still: neither has a reliable, citable pharmacokinetic study behind the numbers commonly attached to them. The 1.5-3 hour or "3-4 day biological duration" figures attached to TB-500, and the 25-60 minute figures attached to GHK-Cu, trace to vendor and blog sources recycling each other, not to a peer-reviewed measurement. AOD-9604's only characterised pharmacokinetics come from a porcine model (about 3 minutes IV, undetectable in spiked plasma by 56 minutes); despite AOD-9604 having gone through human Phase II obesity trials, no confirmed human plasma half-life study surfaced in this research pass.

BPC-157regeneration

Gastric pentadecapeptide (15 amino acids) known for exceptional tissue repair properties. Promotes wound healing, angiogenesis, and cytoprotection across tendons, muscles, gut, and nerves. Over 30 years of preclinical research.

TB-500regeneration

Full-length 43-amino-acid Thymosin Beta-4, a naturally occurring repair protein, independently confirmed by a third-party CoA from Janoshik. Promotes cell migration and new blood vessel formation for systemic tissue healing. Especially researched for muscle, tendon, and cardiac repair.

AOD-9604metabolic

Modified hGH fragment (177-191) studied for fat metabolism and lipolysis research. Interacts with beta-3 adrenergic receptors without growth-promoting effects.

GHK-Culongevity

Naturally occurring copper tripeptide complex for skin regeneration and anti-aging research. Stimulates collagen synthesis, accelerates wound healing, and modulates 4000+ genes. Plasma levels decline with age, making it a key target in longevity research.

Mitochondrial and longevity peptides: mostly unmapped territory

This is the class with the largest gap between how often a peptide is discussed and how much verified pharmacokinetic data actually exists for it. MOTS-c is the clearest example: no administered-peptide human dosing trial existed at all until a Phase 2a study (NCT07505745) began dosing in February 2026 and is still recruiting. Every prior "human MOTS-c data point" is an observational endogenous serum-level measurement (roughly 2.2-3.9 ng/mL across athlete versus sedentary cohorts, PMID 39077591), not a measured clearance rate after administration. The commonly cited 45-90 minute MOTS-c half-life figures are unverified extrapolations from rodent and Humanin-analogy reasoning.

Epitalon has no published human pharmacokinetic study at all; the 30-minute to 3-hour figures attached to it in vendor material are theoretical extrapolations based on how short unprotected linear peptides generally behave, not a measured value. Thymalin and SS-31 (elamipretide) likewise had no reliable primary source located in this research pass, and NAD+, while not a receptor-targeted signalling peptide in the same sense as the others, has no verified single half-life figure we could confirm either. Thymosin alpha-1 stands out as the one well-documented exception in this class: its elimination half-life is under 3 hours after subcutaneous injection in healthy volunteers, with linear pharmacokinetics across a 0.8-6.4 mg dose range and no meaningful accumulation on twice-weekly dosing (PMID 10027483).

MOTS-clongevity

Mitochondrial-derived signaling peptide (16 amino acids) that mimics the effects of exercise at the cellular level. Activates AMPK, improves glucose uptake, and enhances fat metabolism - a key tool in metabolic and longevity research.

Epitalonlongevity

Tetrapeptide (Ala-Glu-Asp-Gly) that activates telomerase, the enzyme responsible for maintaining telomere length. One of the most studied peptides in longevity research, developed by Prof. Khavinson at the St. Petersburg Institute of Bioregulation.

Thymalinlongevity

Thymus-derived immune peptide developed by Prof. Khavinson. Restores T-cell function and thymic activity that naturally decline with age. Over 40 years of clinical use in Russia for immune support and anti-aging research.

Thymosin Alpha-1longevity

Synthetic 28-amino-acid immunomodulatory peptide. Approved as Zadaxin in 35+ countries for chronic hepatitis B and C. Studied in 30+ trials across 11,000+ subjects for immune modulation via TLR2/9 dendritic cell signaling.

SS-31longevity

Mitochondria-targeted tetrapeptide (Elamipretide) that stabilizes cardiolipin and prevents ROS formation at the source.

NAD+longevity

Essential cellular coenzyme that declines with age. Powers energy metabolism in every cell, activates sirtuins (longevity genes), and supports DNA repair. A cornerstone molecule in aging and longevity research.

Cognitive and other short peptides: the "no human data" cluster

LL-37, KPV, DSIP, semax, and selank share a pattern: they are widely discussed with specific-sounding half-life numbers, and none of those numbers trace back to a verified primary human pharmacokinetic study. LL-37's commonly cited 90-120 minute figure is not attached to any confirmed primary source; what is well established is its baseline homeostatic plasma concentration (0.2-0.5 micromolar), a different kind of measurement entirely. KPV has no human pharmacokinetic data whatsoever, only cell-culture and rodent work. DSIP's often-cited 15-minute figure is real, but it describes in vitro molecular stability (degradation by a specific aminopeptidase-like enzyme, PMID 6548966), not an in vivo plasma clearance rate, a distinction that matters when the same number gets reused as if it answered a different question. Semax's 2-5 minute figure derives from animal and in vitro enzymatic degradation studies, not a human plasma measurement. Selank has no dedicated pharmacokinetic study at all; its structural parent, tuftsin, clears in seconds, but that does not establish Selank's own figure.

Melanotan II is a partial exception, with a Phase 1 pilot clinical study reporting an elimination half-life of about 33 minutes via bi-exponential decay analysis of subcutaneous dosing. IGF-1 LR3 sits in an unusual position: no formal human clinical pharmacokinetic trial has ever evaluated it for any endpoint. The 20-30 hour figure attached to it (versus 12-15 minutes for native IGF-1) is a mechanistic inference from its roughly 100-fold reduced affinity for IGF-binding proteins, not a measured human value.

LL-37regeneration

Cathelicidin-derived antimicrobial peptide (37 amino acids). Researched for innate immunity, antimicrobial activity, and wound-healing pathways. ≥98% HPLC purity with Janoshik CoA.

KPVregeneration

Anti-inflammatory tripeptide derived from alpha-MSH (positions 11-13). Inhibits NF-kB signaling, supports gut barrier integrity, and shows antimicrobial activity. A targeted approach to inflammation research without broad immunosuppression.

DSIPcognitive

DSIP (Delta Sleep-Inducing Peptide), a nonapeptide isolated in 1977. Research material for sleep, HPA-axis, and stress regulation. Research-grade lyophilized powder, laboratory use only.

Semaxcognitive

Brain-boosting nootropic peptide derived from ACTH. Increases BDNF (brain-derived neurotrophic factor), enhances focus, memory, and mental clarity. Widely used in Russian clinical practice for cognitive enhancement.

Selankcognitive

Synthetic tuftsin analog with anxiolytic, nootropic, and immunomodulatory properties. Developed at the Russian Academy of Sciences.

Melanotan-2growth

Tanning peptide that activates melanin production in the skin. Stimulates melanocyte receptors for natural UV-free pigmentation. Also researched for appetite regulation and libido effects.

IGF-1 LR3growth

Long R3 variant of Insulin-like Growth Factor 1, modified for reduced IGFBP binding and ~20-30 hour half-life. Researched for cell proliferation, hypertrophy, and metabolic signaling. ≥98% purity.

Metabolic Researchmetabolic

GIP/GLP-1/Glucagon agonists and metabolic pathways

What half-life means for research handling, not for dosing advice

In clinical trial design, half-life is one of the inputs that determines how often a study protocol re-doses a compound, a peptide with a multi-day half-life supports weekly trial visits, a peptide clearing in minutes supports continuous infusion or frequent bolus designs in the studies that establish it. That is a statement about trial design, not a recommendation: this chart explains why published protocols use the dosing intervals they use, it is not a guide to a dosing schedule.

For laboratory handling, half-life data is largely irrelevant to reconstitution and storage; those are governed by the physical and chemical stability of the lyophilised or reconstituted peptide (bacteriostatic water pH, storage temperature, freeze-thaw cycles), not by how fast the peptide clears from a bloodstream once administered. Our reconstitution calculator and unit converter address the reconstitution side directly; this chart addresses a separate question, elimination kinetics after administration in a study.

Where these figures come from

Every sourced figure in this chart was checked against a PubMed record, a PMC full-text article, a journal publisher page, or an FDA prescribing label. Figures with a PMID listed were independently confirmed (title, journal, year, and the specific half-life figure verified against the record). A handful of figures (sermorelin, tesamorelin, GHRP-6, GHRP-2, hexarelin, melanotan II, kisspeptin) rest on a plausible primary source that could not be independently re-confirmed with a specific PMID in this pass; those rows say so explicitly rather than presenting borrowed confidence as verified fact.

This same standard, dose, model, and citation traced to a specific study rather than repeated from memory, is what we apply across our study reference pages and every product page. Every batch we sell also ships with a third-party Janoshik or Liquilabs certificate of analysis, and our purity page documents how we read those chromatograms. A half-life chart and a certificate of analysis answer different questions, one describes clearance kinetics from the literature, the other describes what is actually in a specific vial, but both rest on the same principle: cite the source, or say plainly that you cannot.

Frequently asked questions

This chart is provided for research and informational purposes only. All peptides referenced are sold exclusively as research material, not for human consumption or therapeutic use, and no dosing schedule is implied or recommended.