Research brief

GHK-Cu

Also written as Copper tripeptide-1, glycyl-L-histidyl-L-lysine copper complex

Evidence read from: PubMed, FDA · how we work · Last reviewed 9 August 2026

GHK-Cu is more interesting than most research peptides because it is not a case of missing evidence. It is a case of weak evidence that has been repeated until it sounds strong. The molecule is genuinely endogenous, its collagen effects in cell culture were reproduced by an independent French group forty years ago, and there is one striking wound-healing trial from 1994. What is missing is almost everything in between, and the chain of custody for the famous cosmetic results runs largely through one commercially interested party citing unrefereed abstracts.

Marketed for

Skin aging and wrinkles, wound healing, hair growth, tissue repair.

Evidence reviewed

9 August 2026, against 24 sources

Human evidence

Graded, for members. See the membership

If you read nothing else

• •Exactly one randomized controlled trial of topical GHK-Cu on human skin is indexed in PubMed. It had thirteen completers, and every objective instrumented measure, erythema, wrinkles and skin quality, was null. Only the patient questionnaire reached significance.
• •The famous "71 women facial cream" and "41 women eye cream" studies are 2002 conference posters. They were never published as peer-reviewed papers. Their design, blinding, effect sizes and funding cannot be checked by anyone.
• •The vitamin C and retinoic acid comparison that circulates everywhere appeared in a defunct, unindexed journal, has no PMID, and describes itself in its own title as a pilot.
• •The most-repeated fact about GHK, that plasma levels fall from about 200 to about 80 nanograms per milliliter between ages 20 and 60, traces to an unpublished 1973 doctoral thesis by the peptide’s discoverer. We found no independent replication of that age curve.
• •The 1994 diabetic foot ulcer trial reported a very large benefit. It has not been replicated in a second published human trial in more than thirty years, and an independent irradiated-rat model published later found no effect at all.
• •There is no controlled human trial of injected GHK-Cu as a single agent. The FDA notes that compounded injectable products may pose immunogenicity risk and that "there are limited data in humans to inform safety-related considerations".

Five of the sources, and what they say

Open any of them. Each is tagged with the kind of evidence it is, because a randomized trial in people and an experiment in cell culture answer very different questions. This brief was written against 24 sources of this kind.

1. 1.In vitro
   Pickart L, Thaler MM. Tripeptide in human serum which prolongs survival of normal liver cells and stimulates growth in neoplastic liver. Nature New Biol. 1973;243(124):85-87. PMID 4349963. Open source
2. 2.In vitro
   Pickart L, Thayer L, Thaler MM. A synthetic tripeptide which increases survival of normal liver cells, and stimulates growth in hepatoma cells. Biochem Biophys Res Commun. 1973;54(2):562-566. PMID 4356974. Open source
3. 3.In vitro
   Maquart FX, Pickart L, Laurent M, et al. Stimulation of collagen synthesis in fibroblast cultures by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+. FEBS Lett. 1988;238(2):343-346. PMID 3169264. Open source
4. 4.Animal
   Maquart FX, Bellon G, Chaqour B, et al. In vivo stimulation of connective tissue accumulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ in rat experimental wounds. J Clin Invest. 1993;92(5):2368-2376. PMID 8227353. Open source
5. 5.Human RCT
   Miller TR, Wagner JD, Baack BR, Eisbach KJ. Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin. Arch Facial Plast Surg. 2006;8(4):252-259. PMID 16847171. Thirteen completers; all objective endpoints null. Open source

Members read on

The grade and the full review are for members

The findings above are free, and so are the sources. Behind this line is our grade for the human evidence on GHK-Cu, the full review, what we looked for and could not find, and all 24 sources with the kind of evidence each one is.

The grade is our judgment, and the review is the working behind it: what has actually been run in people, what it measured instead, who ran it, who paid for it, and which results were never published at all. Our findings are above and our sources are open, so nothing here asks you to take the reasoning on trust. What a membership buys is where we land, and why.

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