Educational reference, not medical advice. This page summarizes information from published research and regulatory filings for educational purposes. It is not a recommendation to use any compound and should not replace guidance from a licensed healthcare provider. Most peptides discussed here are not approved for the uses described.
What it is
GHK-Cu is the copper(II)-complex of glycyl-L-histidyl-L-lysine, a tripeptide present in human plasma at concentrations of around 200 ng/mL at age 20, declining to under 80 ng/mL by age 60. The peptide-copper complex is what is typically used in research and skincare; the free GHK peptide and the bound complex behave somewhat differently in tissue.
History
GHK was identified by Loren Pickart in 1973 during studies of why older human plasma was less effective than young plasma at supporting liver tissue regeneration in vitro. Pickart's lab subsequently showed that the active fraction was a small tripeptide and that it operated as a copper-binding protein. The copper complex form (GHK-Cu) was demonstrated to be the biologically relevant species for most healing effects.
Through the 1980s and 1990s the peptide became a mainstream cosmetic ingredient — present in dozens of skincare lines as "copper peptide" or "tripeptide-1" — based on topical work showing improved fibroblast proliferation, collagen synthesis, and skin appearance. Injectable systemic use is a more recent and far less documented application.
Regulatory status
Topical GHK-Cu is approved as a cosmetic ingredient in the United States, EU, Japan, and most jurisdictions, and has decades of safety data in skincare. Injectable GHK-Cu has no regulatory approval anywhere. Compounding pharmacies in the United States cannot prepare it as a sterile injectable for therapeutic use.
Mechanism
A 2010 Broad Institute Connectivity Map analysis (cited in the Pickart 2015 paper) found that GHK modulates the expression of more than 4,000 human genes — by a factor of two or more — toward youthful expression patterns. Specific effects characterized in cell and animal studies include:
- Stimulation of collagen and elastin synthesis by dermal fibroblasts.
- Enhancement of decorin production (a small leucine-rich proteoglycan).
- Modulation of antioxidant defense (induction of superoxide dismutase, glutathione peroxidase).
- Anti-inflammatory effects via NF-κB suppression and TNF-α reduction.
- Copper delivery to lysyl oxidase, the enzyme that cross-links collagen and elastin.
These effects are well documented in vitro and in topical animal models. Systemic injection effects in humans have not been characterized in controlled trials.
Half-life and dosing intervals
Published data places the circulating half-life of GHK-Cu at roughly 30 to 60 minutes after subcutaneous injection. The copper binding gives the peptide rapid tissue distribution.
In research peptide channels, observational protocols describe subcutaneous doses of 1 to 3 mg per day for short courses (4–8 weeks), often broken into multiple smaller injections per day for skin-focused protocols. No controlled human trial supports these regimens.
Topical formulations (creams, serums) deliver GHK-Cu through the stratum corneum at concentrations of 0.05% to 0.2% — a different exposure pattern and the only one with substantive human evidence.
Reconstitution example
GHK-Cu vials are typically 50 mg or 100 mg of lyophilized powder. A 50 mg vial reconstituted with 2 mL of bacteriostatic water yields 25 mg/mL. On a 1 mL U-100 insulin syringe, 4 units (0.04 mL) delivers 1 mg. The blue color of reconstituted GHK-Cu (from the copper) is a useful sanity check that the complex is intact.
What to know
- Topical use is well documented; injectable use is not. Most published evidence applies to topical formulations and cell culture.
- Copper exposure. GHK-Cu delivers copper as part of the complex. Total copper from typical research doses is modest, but Wilson's disease and certain chronic kidney conditions are absolute reasons to avoid copper supplementation.
- Storage. Lyophilized: refrigerate, protect from light. Reconstituted: refrigerate; the blue color should remain consistent. Discoloration or precipitate indicates degradation.
- Reported side effects in user reports include injection-site irritation; the copper component can cause local discoloration if administered superficially.
Sources
- 1.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.
- 2.Pickart L et al. (2015). GHK and DNA: resetting the human genome to health. BioMed Research International.
- 3.Maquart FX et al. (1988). Stimulation of collagen synthesis in fibroblast cultures by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+. FEBS Letters.
- 4.Hostynek JJ et al. (2010). Human stratum corneum penetration by copper: in vivo study after occlusive and semi-occlusive application of the metal as powder. Food and Chemical Toxicology.