Overview

GHK is the tripeptide glycyl-L-histidyl-L-lysine, first isolated from human plasma by Loren Pickart in 1973. It binds copper(II) with high affinity to form the complex GHK-Cu, which is the form most frequently studied. Plasma GHK levels decline with age from approximately 200 ng/mL at age 20 to roughly 80 ng/mL at age 60, a pattern that motivated much of the early research interest in its supplementation.

Most of the published GHK-Cu literature is in cell culture and topical animal-model studies of skin, wound repair, and hair follicles. Systemic (subcutaneous) protocols appear primarily in community writeups rather than published clinical trials.

Mechanism (as reported in the literature)

  • Extracellular matrix remodelling. Studies indicate GHK-Cu upregulates fibroblast synthesis of collagen and elastin and modulates the balance of matrix metalloproteinases and tissue inhibitors of metalloproteinases.
  • Wound-repair signalling. Animal studies of full-thickness wound models report accelerated closure, angiogenesis, and increased granulation tissue.
  • Antioxidant activity. Research characterises copper-binding as blunting the pro-oxidant activity of free copper while supporting copper-dependent enzymes such as superoxide dismutase and lysyl oxidase.
  • Gene-expression profiling. Studies using the Broad Institute Connectivity Map identified GHK as producing a gene-expression signature that reverses a substantial fraction of the aged-skin transcriptome (Pickart et al., 2015; PMID 25945121).

Research findings

  • Topical cosmetic studies. Multiple placebo-controlled studies of topical GHK-Cu creams have reported improvements in skin thickness, fine-line depth, and elasticity metrics over 12-week intervals (Leyden et al., Journal of the American Academy of Dermatology, 2002; Finkley et al., 2005).
  • Wound-repair animal models. Animal studies of ischemic wounds and diabetic wounds report accelerated healing with topical or peri-wound GHK-Cu.
  • Hair follicle biology. In vitro follicle-dermal-papilla studies report increased proliferation and prolonged anagen-phase markers.

Common dosing (from research protocols and community writeups)

Topical formulations most commonly report 0.1–2% GHK-Cu concentrations. Subcutaneous dosing described in community writeups typically falls in the 1–3 mg range per administration, every other day. These are figures reported in the literature, not recommendations.

Reconstitution

Diluent choice matters for GHK-Cu. The peptide-copper complex is less stable in bacteriostatic water than in sterile saline or acidified diluents, and benzyl alcohol can interact with the copper coordination sphere. The most frequently reported research reconstitution uses sterile water or 0.9% sodium chloride, kept refrigerated and used within a shorter window than a typical BAC-water reconstitution.

A 50 mg vial reconstituted with 5 mL of diluent yields a 10,000 mcg/mL solution. Under those conditions:

  • 1 mg (1,000 mcg) = 0.10 mL = 10 units on a U-100 syringe
  • 2 mg (2,000 mcg) = 0.20 mL = 20 units

Storage

Reconstituted GHK-Cu is described as sensitive to heat and light. Refrigerated storage (2–8 °C) in an amber vial is standard in reported protocols; solutions are typically used within 14 days.

  • BPC-157 — a distinct pentadecapeptide studied in tissue-repair contexts.
  • TB-500 — a fragment of thymosin beta-4 studied in wound repair.
  • KPV — the C-terminal tripeptide of alpha-MSH, studied in inflammation research.

Common stacks

References

  • Pickart, L., Vasquez-Soltero, J. M., Margolina, A. (2015). “GHK peptide as a natural modulator of multiple cellular pathways in skin regeneration.” BioMed Research International. PMID 26236730.
  • Pickart, L., Margolina, A. (2018). “Regenerative and protective actions of the GHK-Cu peptide in the light of the new gene data.” International Journal of Molecular Sciences, 19(7). PMID 30012980.
  • Hong, Y., et al. (2015). “The role of copper peptide GHK-Cu in skin anti-aging.” Cosmetics, 2(4).
  • Finkley, M. B., et al. (2005). “Copper peptide and skin.” Cosmeceuticals and Active Cosmetics: Drugs vs. Cosmetics, 2nd ed. Marcel Dekker.