GHK-Cu

GHK-Cu (glycyl-L-histidyl-L-lysine copper) is a naturally occurring tripeptide — three amino acids — with high affinity for copper ions. It was first identified in human plasma, where it appears to decline with age (plasma levels are reportedly highest in young adults and fall substantially by age 60). GHK-Cu has been studied for its roles in wound healing, tissue regeneration, collagen synthesis, antioxidant activity, and anti-inflammatory signaling. It appears to modulate gene expression across a large number of genes related to tissue repair and remodeling, and has been detected in wound fluid, urine, and saliva.¹

GHK-Cu exists in two commercially and regulatory distinct contexts that must be understood separately:

Topical cosmetic use: GHK-Cu is widely used as an ingredient in topical skincare products — serums, creams, and eye treatments — where it is sold as an OTC cosmetic ingredient under the name "copper tripeptide-1." These products are regulated as cosmetics by the FDA, not as drugs, and are widely commercially available. The evidence for topical GHK-Cu in skin aging includes a number of small clinical studies showing improvements in skin texture, firmness, and fine lines when applied topically.

Injectable use: GHK-Cu is used in the research peptide community as a subcutaneous injectable for systemic tissue repair, anti-aging, and wound healing applications. This use is entirely distinct from the cosmetic application and is not FDA-approved.¹

Topical: Skin anti-aging (fine lines, firmness, texture), wound healing, hair loss (some shampoo and serum formulations). Evidence for topical applications includes small randomized trials showing modest improvements in skin parameters.

Injectable (research use): Systemic tissue repair, anti-aging, and wound healing. Evidence is primarily preclinical; no randomized controlled trials have been published specifically for injectable GHK-Cu in humans.

Topical: Applied to skin as directed per individual product formulations; concentrations in cosmetic products vary.

Injectable (research use): No established or approved dose. Community protocols vary widely.

Topical (cosmetic, widely available OTC). Subcutaneous injection (research use, not FDA-approved).

Topical products: per individual product instructions, typically room temperature away from heat and light. Injectable reconstituted solution: refrigerate and use promptly.

Topical use: Generally very well tolerated. Copper peptides at cosmetic concentrations have an established safety profile from decades of use. Avoid combining high-concentration vitamin C with copper peptides in the same application, as they may interact and reduce efficacy of both.

Injectable use: Safety profile for systemic injectable GHK-Cu in humans is not characterized. The route-specific concerns about immunogenicity, impurity characterization, and absence of safety data that the FDA cited for Category 2 peptides apply here.¹

Topical GHK-Cu (copper tripeptide-1) is an OTC cosmetic ingredient regulated under FDA cosmetic regulations. It is not a drug and does not require FDA approval for cosmetic use.

Injectable GHK-Cu is on the FDA's 503A interim bulk drug substances Category 2 list, meaning compounding pharmacies may not legally compound injectable GHK-Cu for human use. The FDA cited the same immunogenicity and safety data concerns as for other Category 2 peptides.¹ This is an important distinction: the approval status and safety profile of the topical cosmetic ingredient does not extend to the injectable form, and they should not be conflated.