A copper-binding tripeptide found naturally in human plasma, widely used in cosmetics and sold online as an injectable anti-aging and healing peptide. Topical versions have small, old studies in wound healing and skin, while the FDA has flagged injectable GHK-Cu as a safety risk with limited human data.
GHK is a three-amino-acid peptide, glycyl-histidyl-lysine, that circulates in human plasma and declines with age, and it binds copper with an affinity similar to the copper site on albumin. The copper complex acts as a repair signal: it attracts immune and capillary cells to an injury, stimulates fibroblasts to make collagen, glycosaminoglycans, and decorin, and modulates the enzymes that remodel damaged tissue. In fibroblast cultures it stimulated collagen synthesis at concentrations as low as a trillionth of a mole per liter. The same sequence sits inside type I collagen, so it may be released by enzymes at a wound site.
Applied to the skin (1/6)
GHK-Cu, a copper-carrying peptide found in human blood, is applied to the skin.
Applied to isolated human skin, copper from the tripeptide crossed the skin and also stayed in the tissue as a depot, which is the basis for topical anti-inflammatory use. Gene expression studies suggest it can shift the activity of thousands of genes toward a repair pattern, a claim that comes from one research group and from cell culture. What the peptide does when injected into a person, how it distributes, and whether the copper load matters are unstudied. The leap from a wound gel to systemic rejuvenation has no human data behind it.
GHK-Cu is sold in serums and creams for wrinkles, hair, and skin repair, and increasingly as an injectable peptide for whole-body anti-aging and recovery. The best human evidence is topical: a randomized, blinded trial of a GHK-Cu gel in diabetic foot ulcers reported 98.5% median wound closure against 60.8% with vehicle and fewer ulcer infections, 7% versus 34%. A small trial after CO2 laser resurfacing in thirteen patients found no objective difference in redness or wrinkles but higher patient satisfaction. Nothing has tested injected GHK-Cu in people.
In cosmetic products it is marketed to tighten skin, reduce wrinkles, and improve firmness. Injectable products come from compounders and research-chemical vendors, and the FDA lists injectable GHK-Cu among compounded substances that may present significant safety risks because of aggregation, impurities, and limited human data. Non-injectable GHK-Cu was under evaluation for compounding until the nominators withdrew it in 2026. A placebo-controlled trial of a topical gel on standardized wounds in 60 healthy adults began recruiting in 2026.
The human evidence is topical, narrow, and mostly old: a multicenter diabetic ulcer trial, a 13-patient post-laser study from 2006, and cosmetic studies on aged skin summarized in reviews by the peptide's discoverer. Mechanistic support is broad, from fibroblast collagen studies in 1988 to skin penetration work in 2010 and gene expression analyses. A 2026 split-wound trial of a topical gel in 60 healthy adults is the first registered modern study. No study of injected GHK-Cu in humans exists.
The open questions are whether any well-characterized product shows a clinically meaningful effect in a controlled trial, and how much formulation, concentration, and delivery route change the answer. The post-laser trial already showed that satisfaction can rise without any objective change. Injectable use has no efficacy or safety data at all, and the FDA separates it from topical use for that reason. Product identity, from cosmetic blends to compounded vials, is unverified.
Topical GHK-Cu caused no notable harm in the wound and skin studies, and its long use in cosmetics has not produced a safety signal in the published literature. The FDA says compounded injectable GHK-Cu may pose a risk of immunogenicity from aggregation and peptide impurities and that human data to judge its safety are limited. Nothing defines a safe injected dose. Regulators in Australia and Canada name GHK-Cu among unapproved injectable peptides whose contents cannot be verified.
No regulator has approved this compound, and no company is seeking approval.
GHK-Cu is not an approved drug in the United States or elsewhere, though it is a common cosmetic ingredient. The FDA lists injectable GHK-Cu among compounded bulk substances that may present significant safety risks, while non-injectable GHK-Cu was removed from its 503A evaluation list in April 2026 after the nominators withdrew it. Australia's TGA names GHK-Cu among unapproved peptide products promoted online, and Health Canada lists it among seized unauthorized injectable peptides. None of these actions is an approval, a ban, or an efficacy finding.