GHK-Cu

What Is GHK-Cu?

GHK-Cu is the copper(II) complex of the tripeptide Glycine-Histidine-Lysine — one of the smallest biologically active peptides known. It was discovered in 1973 by Dr. Loren Pickart at UCSF, who found that blood serum from younger donors contained a factor that caused older human liver cells to synthesize proteins like younger tissue (Pickart L, Thaler M, Nature New Biology, 1973). That factor was identified as GHK-Cu.

GHK-Cu occurs naturally in human plasma at approximately 200 ng/mL at age 20, declining to approximately 80 ng/mL by age 60. This age-related decline has been linked to diminished tissue repair capacity, making GHK-Cu one of the few peptides where there’s a clear biological rationale for supplementation.

In the cosmetics industry, it’s known as “Copper Tripeptide-1” and is a widely used active ingredient in premium skincare products.

How It Works

GHK-Cu’s mechanism is unusually well-characterized for a peptide in this database. The copper ion is essential — without it, GHK has minimal biological activity. The complex promotes wound healing through multiple pathways: stimulating collagen I, III, and V synthesis, attracting immune cells and endothelial cells to wound sites, increasing production of glycosaminoglycans (the matrix that supports skin structure), and demonstrating antioxidant activity by protecting against lipid peroxidation and UV damage.

The most striking finding comes from the Broad Institute: GHK-Cu modulates expression of approximately 31% of all human genes, and was identified as the top compound (from 1,309 bioactive molecules screened) to reverse a 127-gene emphysema expression signature (Campbell JD et al., Genome Medicine, 2012). This was a robust, multi-institutional study involving Boston University, University of Groningen, UBC, and Penn.

What the Research Shows

Topical Wound Healing: The Strongest Human Evidence

GHK-Cu has the best human clinical data of any non-prescription peptide in our database.

Diabetic ulcer RCT (Mulder GD et al., Wound Repair Regen, 1994): This multicenter, randomized, placebo-controlled trial tested Iamin Gel (2% GHK-Cu) in diabetic plantar ulcers. Results: 98.5% median wound closure vs 60.8% vehicle — healing occurred 3× faster, and infection rates dropped from 34% to 7%. This is a properly designed clinical trial with meaningful results.

Anti-aging RCT (Badenhorst T et al., J Aging Science, 2016): Randomized, double-blind trial in 40 subjects showed 55.8% wrinkle volume reduction vs control over 8 weeks.

Collagen synthesis (Abdulghani A et al., 1998): GHK-Cu increased collagen production in 70% of women vs 50% for vitamin C and 40% for retinoic acid over 12 weeks.

Gene Modulation: Intriguing But Early-Stage

The Broad Institute Connectivity Map analysis (Campbell JD et al., 2012) is genuinely significant computational biology — it identified GHK as the top candidate for reversing disease gene signatures. However, identifying a gene expression match in a database is not the same as proving clinical efficacy. No clinical trial has tested GHK-Cu for emphysema or COPD.

Hair Growth: Animal Evidence Only

Studies in mice suggest Tβ4 and GHK-Cu may promote hair follicle activity (Uno H, Kurata S, J Invest Dermatol, 1993; Liu T et al., J Controlled Release, 2023). No large human RCT for alopecia exists.

PeptideIntel Evidence Assessment: GHK-Cu has the strongest evidence profile of any non-prescription peptide — but only for topical wound healing. The moment you move beyond topical application, the evidence drops to animal-only or computational prediction.

What’s Missing

Despite decades of research, there are critical gaps:

• No human clinical trials for oral GHK-Cu — zero published data on oral bioavailability
• No human clinical trials for injectable GHK-Cu — FDA prohibited injectable compounding in 2023
• No ClinicalTrials.gov registrations found for non-topical routes
• Many key studies were industry-sponsored (ProCyte Corp.) or authored by Pickart, who was affiliated with Skin Biology (a copper peptide product company) — creating potential conflict of interest

If you’re taking oral GHK-Cu capsules, there is no published evidence that the peptide survives digestion and reaches systemic circulation in meaningful quantities.

Safety Profile

Topical GHK-Cu has an excellent safety record across clinical trials and decades of cosmetic use. Copper overload is theoretically possible with high systemic doses, but the small quantities in topical products are not a concern. For oral or injectable routes, no systematic safety data exists in humans.

Legal and Regulatory Status

FDA: GHK-Cu is in Category 1 for non-injectable routes only — meaning topical use can be legally compounded. Injectable GHK-Cu was added to substances with “demonstrable difficulties for compounding” in September 2023 and cannot be legally compounded.

Cosmetic: Widely sold as “Copper Tripeptide-1” in skincare products. This is the most legally straightforward route of delivery.

WADA: Not explicitly listed. For topical use, unlikely to trigger doping concerns. Non-topical routes may fall under the S0 umbrella.

The Bottom Line

GHK-Cu is the rare peptide where the marketing claims for one specific route of delivery are actually supported by human clinical data. If you want to use GHK-Cu for wound healing or anti-aging, topical application is both the most evidence-based and most legally straightforward approach. The jump to oral or injectable GHK-Cu — products that cost significantly more — is not supported by any human research. Stick with what’s proven: put it on your skin.