"GHK-Cu half-life" is searched because the injection schedules on clinic and protocol pages, once a day or once a day on weekdays, raise the obvious question of how long the peptide lasts. Unlike BPC-157, whose half-life was at least measured in rats and dogs, GHK-Cu has no published half-life in any species. This page sets out the one pharmacokinetic study that exists, what the newest review says and does not say, the body's own GHK levels, and what that means in arithmetic. It reports; it recommends no schedule.
The amounts in circulation, with their sources, are on the GHK-Cu dosage page; what clinic pages state about sites and frequency is on how GHK-Cu is injected.
The one pharmacokinetic study
In 1997 three researchers at Kissei Pharmaceutical in Japan published a method for measuring GHK and its breakdown product, histidyl-lysine (HK), in rat plasma, and used it on rats given a single intravenous dose (Endo, Miyagi and Ujiie, J Chromatogr B, PMID 9187381). Their abstract reports one pharmacokinetic finding: "GHK was rapidly degraded to HK, which was eliminated rapidly." It states no half-life, peak level or dose, and this page could read only the abstract, so none is reported here.
Two details in that abstract say more than the conclusion. The plasma samples had o-phenanthroline added "to protect against degradation": the peptide breaks down in drawn blood fast enough that it has to be chemically protected before it can be measured. And the method's detection limit, 50 ng/mL, sits not far below the 80 ng/mL reported for human plasma at age 60: it was built to follow an intravenous dose in rats, not the body's own background level.
Nothing comparable exists for GHK-Cu as the copper complex, for subcutaneous injection, or for people.
| What | Measured? | Where |
|---|---|---|
| Human half-life, any route | No | No study published or registered |
| Rat, intravenous GHK | Breakdown described, no figure in the abstract | Endo 1997, PMID 9187381 |
| Subcutaneous or intramuscular, any species | No | — |
| Topical absorption | Skin-permeation studies in excised skin | Reviewed in Mateescu 2026 |
| Circulating GHK and GHK-Cu after a patch | Registered, not started | NCT07706361 |
Counts and searches as run on 2026-10-29 (PubMed E-utilities; ClinicalTrials.gov API).
What the 2026 review says
The most complete account is a structured evidence-mapping review published in August 2026 by Mateescu and colleagues in Pharmaceutics (PMID 42797253), which searched PubMed, Europe PMC, ClinicalTrials.gov and regulatory sources to 12 August 2026. Its pharmacokinetics section treats GHK-Cu as two problems, the peptide and the copper, "because the two can separate in vivo". Of the peptide it writes that GHK, as a small hydrophilic tripeptide, is a substrate for blood and tissue peptidases, and that free GHK "is therefore expected to have a short systemic half-life". The word is expected: the review cites no measured figure, because there is none to cite.
Of the copper it writes that copper released when the complex comes apart is "rapidly bound by albumin, the exchangeable histidine pool, and ceruloplasmin" and cleared mainly by the liver into bile. GHK-Cu is about 15.8% copper by mass, so a 1 mg amount carries about 0.16 mg of copper, and that copper's fate is the body's ordinary copper handling, not the peptide's. A half-life for "GHK-Cu", if one is ever measured, will need to say which of the two it tracked.
The review's overall judgement on the clinical record: preclinical data are consistent, "but the clinical evidence remains sparse", and GHK-Cu "should be regarded as a promising but unproven therapeutic cargo rather than a clinically validated regenerative drug".
The GHK the body already has
GHK was first found in human plasma, and it is still there. A 2015 review by Pickart and colleagues (PMID 26236730, full text PMC4508379) states that plasma GHK "is about 200 ng/mL" at age 20 and "declines to 80 ng/mL by age 60". Converted at 340.4 g/mol, that is about 0.59 and 0.24 micromoles per litre. A 2021 study (Bossak-Ahmad et al., PMID 34730942) notes that GHK is found mostly in the albumin-rich part of plasma and showed GHK and albumin forming shared copper complexes, which the authors suggest may help carry copper in blood.
The arithmetic below sets an injected amount beside that background. It rests on an assumption, about 3 litres of plasma in an adult, so it is an order of magnitude, not a measurement of anything that reaches the blood.
| GHK in plasma (3 L assumed) | GHK in 1 mg GHK-Cu | GHK in 2 mg GHK-Cu | |
|---|---|---|---|
| Age 20 (200 ng/mL) | ≈600 mcg | 845 mcg (1.4×) | 1,690 mcg (2.8×) |
| Age 60 (80 ng/mL) | ≈240 mcg | 845 mcg (3.5×) | 1,690 mcg (7.0×) |
GHK is 84.5% of the mass of GHK-Cu (340.4 of 402.9 g/mol, PubChem figures used across this site's GHK-Cu pages). The 1 to 2 mg range is the one stated on the clinic and protocol pages recorded on the GHK-Cu dosage page; it is not a label dose, because no injectable GHK-Cu has a label.
What a short half-life would and would not mean
If GHK behaves as its size and the 1997 study suggest, an injected amount would be cut into histidyl-lysine and amino acids within minutes to hours, and a once-daily schedule would leave the added peptide gone for most of the day. That is the same pattern measured for BPC-157 in rats, where the trough before each daily dose was zero. It would not by itself settle whether daily or weekday dosing does anything, because a half-life describes how fast a peptide leaves the blood, not how long an effect lasts. But no study has compared dosing intervals for GHK-Cu against any outcome, injected or topical, so the schedules in circulation rest on neither a pharmacokinetic finding nor a trial.
The arithmetic of the draw is unaffected by any of this. From a 50 mg vial with 2 mL of water the solution is 25 mg/mL and 1 mg is 4 units on a U-100 syringe; with 5 mL it is 10 units. The GHK-Cu vial arithmetic works other vials and volumes, and the GHK-Cu reconstitution page sets them out in tables.
What is not established
Any half-life of GHK or GHK-Cu in people, by any route. Any subcutaneous or intramuscular pharmacokinetic study in any species. How much of an injected amount stays as the intact copper complex rather than splitting into peptide and copper. Whether GHK-Cu given from outside adds to, or simply passes through, the body's own GHK. The one registered study that will measure blood GHK-Cu (NCT07706361) concerns a skin patch and had not started on 2026-10-29. Medibact's GHK-Cu guide covers the compound. Decisions about whether to use it belong with a clinician.
Sources and dates
Opened 2026-10-29: PubMed (NCBI E-utilities) searches "GHK-Cu pharmacokinetics" (11 records) and "(GHK OR glycyl-histidyl-lysine) AND (half-life OR plasma stability OR pharmacokinetic*)" (18 records); abstract of Endo T, Miyagi M, Ujiie A, J Chromatogr B 1997;692(1):37-42 (PMID 9187381); full text of Mateescu DM et al., Pharmaceutics 2026;18(9):1077 (PMID 42797253, PMC13610439), pharmacokinetics and conclusions; full text of Pickart L et al., Biomed Res Int 2015;648108 (PMID 26236730, PMC4508379), introduction; abstract of Bossak-Ahmad K et al., Inorg Chem 2021;60(22):16927 (PMID 34730942); ClinicalTrials.gov API search "GHK-Cu" (4 records) and record NCT07706361 (last updated 2026-07-15). Molecular weights as used on this site's GHK-Cu pages. Concentration, molar and plasma-volume arithmetic by this site; the 3-litre plasma volume is an assumption. Corrections go to the contact page.