GHK-Cu is a small copper-binding peptide made of three amino acids (glycine, histidine and lysine). It occurs naturally in human blood, where levels fall with age, and is a common ingredient in anti-aging skincare.[2] In lab studies it boosts collagen production,[1] but human trials are few and small, and there are no published human studies of GHK-Cu injections, which have recently become popular.[9][15]
This profile covers what GHK-Cu is, what the evidence shows for skin, hair and wound healing, topical vs injected use, side effects, copper safety and its regulatory status.
What is GHK-Cu?
GHK was first isolated from human plasma by Loren Pickart. It is also found in saliva and urine, and it binds copper tightly, forming GHK-Cu, also called copper tripeptide-1.[2] It is sold in serums and creams and, increasingly, as injectable vials, and it is the largest ingredient in the GLOW and KLOW blends.
How GHK-Cu works
In skin cell cultures, GHK-Cu stimulated collagen production at extremely low concentrations.[1] Its discoverer’s reviews report that it influences thousands of genes involved in tissue repair, inflammation and antioxidant defenses.[2][3] Those reviews come from GHK’s discoverer, and a 2026 analysis found about 35% of the GHK-Cu literature includes the same authors, which limits independent confirmation.[10]
GHK-Cu benefits for skin
The skin evidence is weaker than its popularity suggests:
- The famous studies were never published. Frequently cited results, such as improvements in 71 women using a copper peptide face cream, come from a 2002 conference presentation and unpublished reports, not peer-reviewed papers.[2]
- The one published randomized trial was mostly negative. After CO2 laser resurfacing, a GHK-Cu cream did not improve redness, wrinkles or skin quality on objective measures; only patient satisfaction was higher.[4] In that 2006 study, only 13 patients finished. Redness was judged by computer analysis and by evaluators who did not know which regimen each patient used, and wrinkles were scored at 12 weeks. Everyone’s skin improved after the laser, with or without GHK-Cu. The only difference was a questionnaire on overall skin quality, which favored GHK-Cu.[4]
- Reviews agree evidence is thin. A 2025 review noted a “surprising absence” of clinical studies for anti-wrinkle use,[6] and a 2026 systematic review found only two randomized trials among 20 studies.[7]
- Newer work: a 2026 Chinese study reported fewer wrinkles with a cream combining GHK-Cu and a ferment extract.[20]
GHK-Cu for hair growth
- Eyebrows: in a 2026 randomized, double-blind, split-face trial in Thailand, 18 adults applied a 2% GHK-Cu serum to one brow for 12 weeks. Hair count and thickness increased on the treated side, with no serious side effects.[11]
- Scalp: in 7 men with pattern hair loss, monthly microneedling with a mix of minoxidil, dutasteride and copper peptides produced strong regrowth, but copper’s own contribution cannot be separated.[12]
- Animals: copper peptide complexes stimulated hair follicles in mice.[13]
GHK-Cu for wound healing
In 86 patients with venous leg ulcers, a copper tripeptide cream did no better than placebo.[5] That 1992 trial, run at the University of Texas Medical Branch in Galveston, compared three creams with evaluators who did not know the assignments: 0.4% copper tripeptide, 1% silver sulfadiazine (an older wound cream) and an inactive placebo. Only silver sulfadiazine shrank the ulcers more than placebo.[5] In Russia, researchers in Kursk found that GHK (without copper) did not significantly speed healing of infected wounds in rats, though a modified version did,[18] and that GHK helped bone repair in rats with fractures.[19]
GHK-Cu injection vs topical
| Topical (creams, serums) | Injection | |
|---|---|---|
| Human studies | A few small trials[4][11] | None published[8][15] |
| Regulatory status | Legal cosmetic ingredient | Not FDA-approved; FDA flagged immune-reaction risks[16] |
| Expert view | Dermatologists consider it reasonable[15] | Dermatologists interviewed by NPR advise against[15] |
A 2026 sports medicine primer found no clinical data supporting injectable GHK-Cu for joint or tendon problems.[8] A nurse practitioner interviewed by NPR described seeing injection-site reactions, infections and liver problems after unsupervised use.[15]
GHK-Cu side effects and copper safety
- Topical: in the Thai eyebrow trial, there were no serious side effects or allergic reactions.[11]
- Injection: FDA has said injectable GHK-Cu may pose a risk of immune reactions due to clumping and impurities, with limited human data.[16]
- Copper: the NIH sets the upper limit for adults at 10 mg of copper a day from food and supplements, based on liver damage at higher intakes; people with Wilson’s disease are at particular risk.[14] For comparison, adults need about 900 micrograms (0.9 mg) of copper a day, and too much over time can cause stomach pain, nausea, vomiting and diarrhea as well as liver damage.[14] A 2026 review cautions that these oral limits cannot be converted directly into limits for injections.[9]
GHK-Cu dosage: what has been studied
| Setting | Dose |
|---|---|
| Eyebrow trial | 2% serum twice daily for 12 weeks[11] |
| Leg ulcer trial | 0.4% cream[5] |
| Rat fracture study (Russia) | 0.5 micrograms per kg into the fracture site[19] |
| Injection in humans | Never studied[15] |
For converting a vial’s milligrams into syringe units, see our peptide calculator.
What users report
Is GHK-Cu legal?
- Cosmetics: GHK-Cu is legally sold in skincare products.
- Not an approved drug: it is not part of any FDA-approved medicine.[17]
- Compounding: FDA placed injectable GHK-Cu on its list of substances with possible significant safety risks in 2023. In April 2026 it was removed after the nomination was withdrawn, and in May 2026 FDA confirmed it is still evaluating GHK-Cu for non-injectable uses, with an advisory committee review planned before the end of February 2027.[16][17]
- Sport: GHK-Cu is not named on WADA’s 2026 Prohibited List.[25]
This is general information, not legal advice.
