No injectable evidenceGHK-Cu is not an FDA-approved drug.[1] For injectable GHK-Cu the FDA says there are "limited data in humans to inform safety-related considerations", and we found no published human trial of it by injection. This calculator does arithmetic only.
What is GHK-Cu? The copper peptide explained
GHK-Cu is the best-known of the copper peptides: a small peptide carrying a copper ion. GHK is the tripeptide glycyl-L-histidyl-L-lysine (340.38 g/mol without copper). GHK-Cu is its copper(II) complex. PubChem lists several GHK-Cu records with slightly different formulas; this page uses CID 71587328, "prezatide copper", at 402.92 g/mol.[24] Different records, salts and copper ratios mean a vial labeled GHK-Cu may not match this weight exactly.
How GHK holds copper, and how tightly
GHK grips copper(II) through three nitrogen atoms from a single peptide: the glycine amino nitrogen, the deprotonated histidine peptide-bond nitrogen and an imidazole nitrogen, leaving a fourth, easily exchanged site.[13][14] In water the complex is a 1:1 molecule; in the crystal it is not.
| Study | Method | What it found |
|---|---|---|
| Perkins 1984[12] | X-ray crystallography, 1.1 Å | A coordination polymer, not a discrete molecule: each copper is held by one peptide through three nitrogens, and its remaining two sites are filled by carboxylate oxygens from two neighbouring peptides. Four donors at about 2.00 Å, one apical at 2.49 Å |
| Freedman 1982[13] | EPR, electron spin-echo, optical | That polymer "does not exist in solution". In water the complex is mononuclear and 1:1, with the imidazole ring confirmed in the copper's equatorial plane |
| Hureau 2011[14] | X-ray with EPR, HYSCORE, XAS and NMR | The same split, with modern methods: dimeric in the solid, monomeric in solution |
| Lau & Sarkar 1981[15] | Potentiometry and visible spectrophotometry, 25 °C, 0.15 M NaCl | The famous stability constant, log β = 16.44 for the 1:1 complex, plus the finding that bis-complexes (two peptides per copper) are extensive at neutral pH and above |
| Trapaidze 2012[16] | Isothermal titration calorimetry at pH 7.4 | A conditional dissociation constant: Kd = 7.0 ± 1.0 × 10−14 M |
| Bossak-Ahmad 2020[17] | Potentiometry with the competitivity-index method | Kd = 0.24 pM at pH 7.4, about 300 times weaker than the calorimetry figure; also identifies six different Cu/GHK species |
- Why a "1:1 molecule" picture is still fair. A reconstituted vial is a solution, and in solution the complex is monomeric.[13][14] The polymer belongs to the crystal, which is how the structure is often mis-described.
- log β 16.44 is not an affinity at body pH. It is an overall formation constant measured against the fully deprotonated peptide.[15] The numbers you can compare with physiology are the conditional ones above, and those two primary measurements differ by roughly 300-fold, so no single figure should be quoted as settled.[16][17]
- Against albumin, measured rather than inferred. Instead of comparing constants, Lau and Sarkar ran an equilibrium dialysis: at equal concentrations and neutral pH, GHK pulled 42% of the copper off copper-albumin, against about 12% for histidine.[15]
- One thing is still unresolved in the primary literature: whether the lysine side-chain amino group joins the copper at body pH. Lau and Sarkar inferred that it does; Conato and colleagues concluded it does not, being protonated below alkaline pH.[15][18] Both are primary potentiometric studies and we take no side.
Where 402.92 g/mol comes from, and what it is not. The arithmetic is GHK (340.38) minus one proton (1.008) plus copper (63.546) = 402.92, so simple addition of peptide and metal does not reproduce it.[24][25][23] But that PubChem record describes a cation of charge +1 with no counterion, and its structure is drawn as a deprotonated peptide beside a copper ion with no bonds between them, while the record's own chemical names describe a doubly deprotonated ligand, which would instead give a neutral complex of 401.91 g/mol.[24] Treat 402.92 as a formula weight rather than the weight of anything you can put on a balance: real GHK-Cu powder is an acetate or trifluoroacetate salt of variable stoichiometry and carries water too, so the vial's certificate of analysis governs any mass calculation.[24]
Does plasma GHK fall with age? The 200 to 80 ng/mL claim
This figure is repeated everywhere and has no primary source. The claim that plasma GHK is about 200 ng/mL at age 20 and about 80 ng/mL by age 60 appears in three review articles by the peptide's discoverer, and in all three the sentence carries no citation at all.[19][20][21]
| Where it appears | Wording | Citation attached? |
|---|---|---|
| Pickart 2012 review[19] | "about 200 micrograms/liter in men of age 20–25 but declines to 80 micrograms/liter by age 60–80" | None |
| Pickart 2015 review[20] | "about 200 ng/mL (10⁻⁷ M) at age 20, but declines to 80 ng/mL by age 60" | None |
| Pickart 2018 review[21] | "At age 20, the plasma level of GHK is about 200 ng/mL … by the age of 60, it declines to 80 ng/mL" | None |
| Deng 2023, the one independent measurement[22] | 133.0 ± 54.5 ng/mL in 11 healthy controls, by reversed-phase HPLC | A primary measurement, but with no age stratification |
- No study behind it. There is no published population, assay method or sample size for the age figures. The only work cited anywhere near those sentences is a 1973 doctoral thesis, cited for the peptide's discovery rather than for any plasma assay, and we could not obtain it.[20]
- The one real measurement does not match. Deng and colleagues measured 133 ± 55 ng/mL in healthy controls age-matched to COPD patients, which sits well above the 80 ng/mL the claim predicts for that age, and they did not compare age groups at all.[22]
- GHK is unstable in plasma. That study added o-phenanthroline to each blood sample at collection "due to the instability of GHK in human plasma" before freezing it, a constraint any casually collected historical dataset would have had to meet.[22]
None of this says the peptide does nothing. It says that one specific, much-quoted pair of numbers has never been published as a measurement, and a page that repeats it is repeating a review's uncited sentence. Our editorial policy is to trace numbers to the study that produced them, and to say so when there isn't one.
Regulatory status: two routes, two answers
GHK-Cu is not an FDA-approved drug, and for compounding the FDA treats non-injectable and injectable forms differently.
| Form | Status | What the FDA wrote |
|---|---|---|
| Injectable[2] | In 503A Category 2 from September 2023; now in the "nominated but withdrawn" table | "Compounded injectable drugs containing GHK-Cu may pose risk for immunogenicity due to the potential for aggregation and peptide-related impurities." |
| Non-injectable (for example topical)[3] | 503A Category 1 (under evaluation) | Removed from Category 1 on April 22, 2026 after the nominations were withdrawn, then restored after a nominator clarified on May 5, 2026 that it meant to withdraw only the injectable nomination. FDA plans to consult its advisory committee before the end of February 2027. |
- Category 1 means a substance is under evaluation and the FDA generally does not intend to take action against compounding with it in the meantime. It is not an approval.[5]
- A 2020 warning letter told a compounding pharmacy that GHK-Cu was not eligible for compounding under 503A at the time.[7]
- GHK-Cu is on the February 2027 agenda. The FDA's meeting page names it as one of five bulk substances the committee will consider for the 503A list, with cathelicidin LL-37, dihexa acetate, melanotan II and pegylated mechano growth factor. The time and location "will be scheduled in the coming months", and no Federal Register notice had appeared by November 14, 2026.[4]
- GHK-Cu is not part of the October 2026 HHS peptide policy.[6]
- GHK-Cu is not named on the WADA 2026 Prohibited List. Whether the list's general S0 clause for non-approved substances applies is for WADA to decide; it has not said.[8]
GHK-Cu side effects and human evidence
For skin-care products, the copper peptide serum page covers the cosmetic rules and topical studies in detail.
Every published human study of GHK-Cu applied it to the skin; none injected it.
| Study | Design | Use | Reported |
|---|---|---|---|
| Mulder 1994[9] | Randomized, evaluator-blinded, vehicle-controlled, multicenter | Topical gel on diabetic foot ulcers | Median closure 98.5% vs 60.8%; infection 7% vs 34% |
| Miller 2006[10] | Randomized, 13 completers | Topical after CO₂ laser resurfacing | No objective difference in redness or wrinkles; higher patient satisfaction |
| NCT07437586[11] | Phase 2, registered 2026 | Topical gel on acute wounds | Recruiting; no results |
The skin studies did not report safety problems, but none tracked side effects of injection, so the side effects of injected GHK-Cu in people are unknown; the FDA flags possible immune reactions from aggregation and impurities.[2] Injected GHK-Cu: no published human trial was found on PubMed or ClinicalTrials.gov. Skin studies do not tell you what happens when the same substance is injected, and the FDA treats the injectable form separately.
GHK-Cu peptide dosage chart (concentration only)
A dose-neutral chart for the arithmetic. Nanomoles use 402.92 g/mol: 1 mg of GHK-Cu is about 2,482 nmol, so the same mass holds far more molecules than any other peptide on this site.
| Vial + liquid | mg/mL | mcg per unit | nmol per unit | Units per 100 mcg |
|---|---|---|---|---|
| 5 mg + 1 mL | 5 | 50 | 124.09 | 2 |
| 5 mg + 2 mL | 2.5 | 25 | 62.05 | 4 |
| 5 mg + 3 mL | 1.667 | 16.67 | 41.36 | 6 |
| 10 mg + 1 mL | 10 | 100 | 248.19 | 1 |
| 10 mg + 2 mL | 5 | 50 | 124.09 | 2 |
| 10 mg + 3 mL | 3.333 | 33.33 | 82.73 | 3 |
For a 100 mg vial the same formulas give 20 mg/mL with 5 mL of liquid, or 200 mcg per unit, so 1 mg is 5 units. Larger vials make each unit hold more, which makes small amounts harder to measure.
Example arithmetic: 10 mg in 2 mL holds 50 mcg per unit, so 1 mg is 20 units. The calculator cannot tell you anything about a solution's quality or identity.
Other peptide pages
The peptides most often looked up alongside this one. Each page gives that peptide's FDA status, compounding status and published human evidence, with sources; the status table has all 23 in one place.
- BPC-157Not approved 15-amino-acid peptide. Human data: a few tiny, uncontrolled studies.
- TB-500Not approved A 7-amino-acid fragment of thymosin beta-4. No human trials of TB-500 itself.
- BPC-157 + TB-500 blendNot approved Two peptides in one vial: the arithmetic of a fixed ratio.
- KPVNot approved Lys-Pro-Val tripeptide. No human data by any route.
- LL-37Not approved Human cathelicidin. Topical wound trials; FDA cites tumor concerns.
- TesamorelinFDA-approved Egrifta SV and Egrifta WR. Labeled doses, diluents and volumes.
Frequently asked questions
Is GHK-Cu FDA-approved?
Has injectable GHK-Cu been studied in people?
We found no published human trial of injected GHK-Cu. The human studies are of gels and creams on the skin.
How many units is 1 mg of GHK-Cu?
From a 10 mg vial with 2 mL it is 20 units; with 3 mL it is 30 units. This is arithmetic, not a suggested amount.
Sources
- openFDA Drugs@FDA searches for BPC-157, thymosin, CJC-1295, ipamorelin, MOTS-c and prezatide (no application found)
- Certain bulk drug substances for use in compounding that may present significant safety risks
- Bulk drug substances nominated for use in compounding under section 503A (category lists)
- February 2027 meeting of the Pharmacy Compounding Advisory Committee (agenda: cathelicidin LL-37, GHK-Cu, dihexa acetate, melanotan II, pegylated mechano growth factor)
- Bulk drug substances used in compounding under section 503A of the FD&C Act
- Enforcement discretion policy regarding 503A compounding using certain peptide bulk drug substances (91 FR 68526)
- Warning letter: Tailor Made Compounding LLC
- World Anti-Doping Code: Prohibited List 2026
- Mulder GD et al. Topical GHK-Cu gel for diabetic neuropathic ulcers (Wound Repair Regen 1994;2:259–69)
- Miller TR et al. Topical copper peptide after CO2 laser resurfacing (Arch Facial Plast Surg 2006;8:252–9)
- NCT07437586: topical GHK-Cu gel for acute wounds, phase 2 (recruiting)
- Perkins CM et al. The structure of a copper complex of the growth factor glycyl-L-histidyl-L-lysine at 1.1 Å resolution (Inorg Chim Acta 1984;82:93–99)
- Freedman JH et al. Structure of the glycyl-L-histidyl-L-lysine–copper(II) complex in solution (Biochemistry 1982;21:4540–4544)
- Hureau C et al. X-ray and solution structures of Cu(II)GHK and Cu(II)DAHK complexes (Chemistry 2011;17:10151–10160)
- Lau SJ, Sarkar B. The interaction of copper(II) and glycyl-L-histidyl-L-lysine, a growth-modulating tripeptide from plasma (Biochem J 1981;199:649–656)
- Trapaidze A et al. Thermodynamic study of Cu(II) binding to the DAHK and GHK peptides by isothermal titration calorimetry (J Biol Inorg Chem 2012;17:37–47)
- Bossak-Ahmad K et al. Ternary Cu(II) complex with GHK peptide and cis-urocanic acid (Int J Mol Sci 2020;21:6190)
- Conato C et al. Copper complexes of glycyl-histidyl-lysine and two of its synthetic analogues (Biochim Biophys Acta 2001;1526:199–210)
- Pickart L, Vasquez-Soltero JM, Margolina A. The human tripeptide GHK-Cu in prevention of oxidative stress and degenerative conditions of aging (Oxid Med Cell Longev 2012;2012:324832)
- Pickart L, Vasquez-Soltero JM, Margolina A. GHK peptide as a natural modulator of multiple cellular pathways in skin regeneration (BioMed Res Int 2015;2015:648108)
- Pickart L, Margolina A. Regenerative and protective actions of the GHK-Cu peptide in the light of the new gene data (Int J Mol Sci 2018;19:1987)
- Deng M et al. GHK-Cu rescues cigarette smoking-induced skeletal muscle dysfunction (J Cachexia Sarcopenia Muscle 2023), reporting plasma GHK by RP-HPLC in 11 healthy controls
- Abridged standard atomic weights 2024
- PubChem CID 71587328: prezatide copper (GHK-Cu)
- PubChem CID 73587: glycyl-L-histidyl-L-lysine (GHK)