Underground Biohacking
Recovery

GHK-Cu

Chris Hallewell, founder of Underground Biohacking

By , Founder, Underground Biohacking

Last reviewed

Research use only. Not FDA-approved.

GHK-Cu is a copper carrying peptide used in skin creams and, increasingly, in unapproved injections. The honest answer is that the human evidence is thin. One small trial after laser resurfacing found better patient rated skin quality but no measurable difference. A larger trial in leg ulcers found no benefit over placebo. Almost everything else comes from rats, rabbits and cell cultures. FDA lists injectable GHK-Cu among substances with limited human safety data.

What is GHK-Cu?

GHK-Cu is a tiny peptide built from three amino acids: glycine, histidine and lysine. Chemists write those as G, H and K, which is where the name comes from. The Cu is copper. The peptide grips a copper ion and holds on to it. That pairing is where most of its claimed activity comes from. It is not a laboratory invention. GHK occurs naturally in human blood, saliva and urine. Researchers who measured it in the blood of patients with chronic lung disease found lower levels than in healthy people of similar age. That is one reason it gets described as a repair signal the body already makes for itself. Structure matters here in two ways. First, the three amino acids form a pocket that binds copper tightly, so the peptide can carry copper into tissue rather than leaving it loose. Second, GHK-Cu is strongly hydrophilic, meaning it loves water and dislikes oil. Your outer skin layer is oily by design. That is why formulators spend so much effort on liposomes and other carriers to get it below the surface. It is also why a cream and an injection are not the same thing.

What is GHK-Cu used for?

  • In a randomised trial of 13 people after CO2 laser resurfacing, users of a GHK-Cu skin care regimen rated their skin quality significantly better.[1]Human study
  • In people with chronic lung disease, blood levels of GHK were lower than in healthy people of similar age and tracked muscle size.[2]Human study
  • In 32 women, a lip product containing a palmitoyl GHK tripeptide improved lip dryness and texture over four weeks.[3]Human study
  • In rat wound chambers, injected GHK-Cu raised collagen, protein and glycosaminoglycan (water holding sugar chains) content in the new tissue.[4]Animal or lab study only
  • In rabbits with open skin wounds, topical copper tripeptide shrank the wounds faster than zinc oxide or no treatment.[5]Animal or lab study only
  • In rats with a poor blood supply to the skin, topical copper tripeptide closed wounds faster than the vehicle or no treatment.[6]Animal or lab study only
  • In cultured human skin fibroblasts, GHK-Cu increased the making of sulfated glycosaminoglycans, which is a cell dish result, not a skin result.[7]Animal or lab study only
GHK-Cu dosage chart
Typical dose1-2mg per injection, 2-3 times per week (injectable). 0.05-2% (topical formulations).
Cycle length12-24 weeks; topical can be continuous
FormInjectable (subcutaneous), topical serum

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How does GHK-Cu work?

GHK is a short peptide, three amino acids long: glycine, histidine and lysine. It grips a copper ion, and that pairing is GHK-Cu. In cultured human fibroblasts, the cells that build your skin's support structure, GHK-Cu switched on collagen production. That effect showed up at very low concentrations. The same GHK sequence sits inside type I collagen itself, so researchers proposed that injury releases it as a local repair signal. That release step is proposed, not demonstrated. Getting it through intact skin is the open question. One human skin study tracked copper crossing, not the whole peptide, so how much intact GHK-Cu gets in is unsettled.

How much GHK-Cu should you take?

1-2mg per injection, 2-3 times per week (injectable). 0.05-2% (topical formulations).

How long should you run GHK-Cu?

12-24 weeks; topical can be continuous

How is GHK-Cu supplied?

Injectable (subcutaneous), topical serum

What are the side effects of GHK-Cu?

EffectHow seriousWhat to watch
No published trial has set out to measure the side effects of injected GHK-Cu in people. Nobody knows the real risk profile.UnknownAny new rash, swelling, fever or reaction at the injection site.
A copper tripeptide cream did no better than placebo on venous leg ulcers in 86 people, so leaning on it can delay real care.[10]Indirect, from treatment delayAny wound that is not steadily closing. Get it looked at.
GHK-Cu carries copper through skin and leaves a copper store behind in the tissue, measured in human skin samples outside the body.[8]Unknown in living peopleHow much you apply and over how large an area, especially alongside other copper products.
In rat wounds, GHK-Cu changed the activity of enzymes that break down and rebuild skin structure. What that does to human scarring is untested.[9]UnknownScar thickness, colour and texture if you use it on healing skin.
Topical tolerance looks mild in the small human work that exists. One four week lip study with a GHK derivative reported no adverse events.[3]None reported in a small, short studyRedness, stinging or itching in the first days of use.

Is GHK-Cu legal in 2026?

Checked on 6 August 2026 against the FDA page listing bulk drug substances for compounding that may present significant safety risks. GHK-Cu appears on that page, in the table of substances that were nominated for compounding and then withdrawn by the nominators. The entry covers injectable routes. FDA writes that compounded injectable GHK-Cu may pose a risk for immunogenicity, because of aggregation and peptide related impurities. Immunogenicity means your immune system may react to it. FDA also states that there are limited data in humans to inform safety. Nothing on that page permits GHK-Cu to be compounded. Topical GHK-Cu sold in cosmetics sits under separate rules, and cosmetic ingredients are not approved by FDA before sale.

Status checked against the primary source.

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Deep dives on GHK-Cu

Frequently Asked Questions

Does GHK-Cu actually reduce wrinkles?
No published trial has shown that convincingly. The randomised human trial we found used GHK-Cu skin care after CO2 laser resurfacing. Blinded evaluators scored wrinkles and overall skin quality, and found no difference between the group that used it and the group that did not. The patients themselves rated their skin as better. That gap, between what people feel and what independent raters can measure, is the whole story with this peptide.
Is GHK-Cu better as a cream or as an injection?
Creams are where the human testing has actually happened, and even there the results are weak. Injections have no published human efficacy trial that we could find. FDA specifically flags injectable GHK-Cu for a possible immune reaction and says human safety data are limited. GHK-Cu also loves water, so it does not cross the oily outer skin layer easily. That is a formulation problem to solve, not a reason to inject it.
Does GHK-Cu regrow hair?
There is no human trial of GHK-Cu for hair loss that we could find. The hair claims trace back to laboratory and animal work, and often to products where GHK-Cu is one ingredient sitting alongside several growth factors. In those cases you cannot tell what the peptide itself contributed. Review articles repeat the claim, but a review is not new evidence. Treat hair regrowth claims for GHK-Cu as untested in people.
Is GHK-Cu safe?
For injections, honestly, nobody knows. No trial has been published that set out to measure the side effects of injected GHK-Cu in people. FDA says the human safety data are limited and flags a possible immune reaction. Topical use has a longer track record and looks mild. One four week study of a lip product containing a GHK derivative reported no adverse events in 32 women. That is one small, short study of one product.
Will GHK-Cu heal a wound or a scar faster?
In animals, fairly consistently yes. Rabbit and rat wound studies found faster closure with topical copper tripeptide than with control treatments. In people, the one sizeable trial tested a copper tripeptide cream on venous leg ulcers and it did no better than placebo. Silver sulfadiazine beat both. So the animal signal is real and the human confirmation has not arrived. Do not use it in place of proper wound care.
What should I ask a doctor before using GHK-Cu?
Ask which route they are proposing and why. Injectable GHK-Cu is not an approved medicine, and FDA lists it among peptides with limited human safety data. Ask where the substance was made and how its purity was tested. Ask what they expect it to do that a proven treatment cannot. If you have a wound, a scar or hair loss, ask what the evidence backed option is first.

References

  1. 1.Miller TR, et al. (2006). Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin. Archives of facial plastic surgery. PMID: 16847171. DOI: 10.1001/archfaci.8.4.252.
  2. 2.Deng M, et al. (2023). Glycyl-l-histidyl-l-lysine-Cu2+ rescues cigarette smoking-induced skeletal muscle dysfunction via a sirtuin 1-dependent pathway. Journal of cachexia, sarcopenia and muscle. PMID: 36905132. DOI: 10.1002/jcsm.13213.
  3. 3.Trookman NS, et al. (2009). Clinical assessment of a combination lip treatment to restore moisturization and fullness. The Journal of clinical and aesthetic dermatology. PMID: 20725584.
  4. 4.Maquart FX, et al. (1993). In vivo stimulation of connective tissue accumulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ in rat experimental wounds. The Journal of clinical investigation. PMID: 8227353. DOI: 10.1172/JCI116842.
  5. 5.Cangul IT, et al. (2006). Evaluation of the effects of topical tripeptide-copper complex and zinc oxide on open-wound healing in rabbits. Veterinary dermatology. PMID: 17083573. DOI: 10.1111/j.1365-3164.2006.00551.x.
  6. 6.Canapp SO, et al. (2003). The effect of topical tripeptide-copper complex on healing of ischemic open wounds. Veterinary surgery : VS. PMID: 14648529. DOI: 10.1111/j.1532-950x.2003.00515.x.
  7. 7.Wegrowski Y, et al. (1992). Stimulation of sulfated glycosaminoglycan synthesis by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+. Life sciences. PMID: 1522753. DOI: 10.1016/0024-3205(92)90504-i.
  8. 8.Hostynek JJ, et al. (2010). Human skin retention and penetration of a copper tripeptide in vitro as function of skin layer towards anti-inflammatory therapy. Inflammation research : official journal of the European Histamine Research Society. PMID: 20703511. DOI: 10.1007/s00011-010-0214-4.
  9. 9.Simeon A, et al. (1999). Expression and activation of matrix metalloproteinases in wounds: modulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+. The Journal of investigative dermatology. PMID: 10383745. DOI: 10.1046/j.1523-1747.1999.00606.x.
  10. 10.Bishop JB, et al. (1992). A prospective randomized evaluator-blinded trial of two potential wound healing agents for the treatment of venous stasis ulcers. Journal of vascular surgery. PMID: 1495150. DOI: 10.1067/mva.1992.37086.

This content is for educational purposes only. These compounds are intended for research use. Nothing here is medical advice.