GHK-Cu (copper peptide): research, side effects and dosage in studies
In short
GHK-Cu is a three-amino-acid peptide bound to a copper ion, and it is used in skin creams [1]D. Its human studies are small cream studies [4], and it has no marketing authorisation as a medicine [7]regulator.
- The interest started in cell cultures: GHK-Cu increased collagen production in connective tissue cells [1]D. The result applies to cells.
- Human studies are small and concern creams and gels applied to the skin. Results are mixed: in diabetic foot ulcers the gel helped [10]A, in leg ulcers the cream did not differ from placebo cream [2]A.
- We found no published clinical trials of injected GHK-Cu, and according to a review its dosing is unknown [5].
- GHK-Cu is in Annex 1 A of Fimea's medicines list, whose substances are always treated like prescription-only medicines [9]regulator. A cosmetic skin cream is still not necessarily a medicine [9]regulator. Fimea warns against injectable peptides bought online [8]regulator.
What is GHK-Cu?
GHK-Cu is a three-amino-acid peptide (glycyl-histidyl-lysine) bound to a copper ion. GHK was originally isolated from human blood plasma, and it binds copper [1]D.
The same three-amino-acid sequence is also found in the structure of type I collagen. Researchers have suggested that it may be released in a wound as tissue breaks down [1]D.
Commercially GHK-Cu is known mainly as an ingredient in skin creams [4]. Powder meant for injection is also sold online. That is a different thing from a cream applied to the skin [5] [6]regulator. Basics: What are peptides?. All substances: Peptides A-Z.
Evidence at a glance
Each cell gives the kind of study and its source. The letter is the evidence level, not the result.
| Claimed effect | Humans | Animals | Cells |
|---|---|---|---|
| Collagen production | No strong human evidence; cream studies are small [4] | - | Increased collagen production in connective tissue cells [1]D |
| Diabetic foot ulcer | Gel on the skin: ulcers closed better than with the vehicle gel [10]A | - | - |
| Venous leg ulcer | 0.4% cream did not differ from placebo cream [2]A | - | - |
| Skin after laser treatment | 13 patients: evaluators saw no difference, patients were more satisfied [3]A | - | - |
| Injection (any use) | No clinical trials found; no clinical data support musculoskeletal use [5] | - | - |
| Safety | No harms reported in small cream studies; little data on injections [2, 3]A [6]regulator | - | - |
"-" = no such study is known.
What is GHK-Cu studied for?
GHK-Cu is studied mainly for skin care and wounds, and in humans almost always as a cream or gel on the skin [4]. No use is approved as a medicine [7]regulator.
- Wounds: diabetic foot ulcers [10]A and venous leg ulcers [2]A.
- Cosmetic skin care: face creams and skin after laser treatment [3]A [4].
- Microneedles: delivering GHK-Cu into the skin with microneedles has not been tested in a single registered, adequately powered human trial [4].
- Muscles, tendons and joints: there is no clinical study supporting this use [5].
Claims online. The claim that GHK-Cu "builds collagen" rests on cell cultures [1]D. More on peptides applied to the skin: Peptides in skincare.
Another peptide studied for wound healing: LL-37 in wound-care trials.
How does GHK-Cu work?
In humans, how GHK-Cu works is not known precisely. In cell culture GHK-Cu increased collagen production in connective tissue cells. The effect started at very low concentrations (10⁻¹²-10⁻¹¹ M, i.e. picomolar concentrations), peaked at 10⁻⁹ M and did not depend on a change in cell number [1]D.
A cell culture result does not tell what happens in human skin or in the body. According to a 2026 systematic review, preclinical data have accumulated over more than four decades, but human studies are few and fragmented [4].
Has GHK-Cu been studied in humans?
A little, and almost only as a cream or gel on the skin. Most randomised trials are small [4]. We found no published clinical trials of injected GHK-Cu.
Human studies
- Diabetic foot ulcers (1994). In a multicentre trial that was randomised, evaluator-blinded and placebo-controlled, GHK-Cu gel was applied to the ulcer daily on top of standard wound care. Ulcers on the sole of the foot closed better with the gel than with the vehicle gel (median closure of area 98.5% vs 60.8%), and there were fewer wound infections [10]A. The abstract does not give the gel concentration [10]A.
- Venous leg ulcers (1992). 86 patients received a 0.4% copper tripeptide cream, silver sulfadiazine cream or an inert placebo cream. Silver sulfadiazine reduced ulcer size, but there was no difference between the copper tripeptide cream and placebo [2]A.
- Skin after laser treatment (2006). Skin around the mouth treated with a CO2 laser was cared for with skin products with or without GHK-Cu. Thirteen patients completed the study. Redness did not resolve faster, and blinded evaluators found no difference in improvement of wrinkles or skin quality. Patient-rated satisfaction with skin quality was higher in the GHK-Cu group (P = .04) [3]A.
- Review (2026). A systematic review screened 1,247 records and kept 64. Randomised human trials are mostly small studies of facial creams [4].
Promising, but only in cell studies
This finding looks good, but it has not been shown in humans. Results from cell studies cannot be transferred to humans, nor do they show the effects of an injectable product sold online [5].
-
Collagen production no human studies
In an early cell culture study GHK-Cu increased collagen production in connective tissue cells at very low concentrations, and the effect did not come from an increase in cell number [1]D.
If it held in humans: skin or a wound could produce more collagen.
Why it might not translate: a cell culture is not skin or a body, and in a small human cream study blinded evaluators saw no difference in improvement of wrinkles or skin quality [3]A. According to a review, about 35% of original GHK-Cu studies from 2005-2026 list the researcher who isolated the peptide, or a researcher from his company, as an author [4].
Evidence now: a cell culture study from 1988 [1]. We found no clinical trials of injected GHK-Cu.
Who studies GHK-Cu?
According to a review, about 35% of original GHK-Cu studies from 2005-2026 list the researcher who isolated the peptide, or a researcher from his company, as an author, which limits the independence of the evidence [4]. The often-cited face and eye cream studies were published only as conference abstracts, not as peer-reviewed articles [4].
Who wrote this page: the editorial team
This page was written by the Molecular Recovery editorial team. The draft was made with the help of AI, and the claims were checked against the sources (AI policy). The page has not been medically reviewed. How we work: About us.
What are the side effects of GHK-Cu?
Little is known about GHK-Cu creams and even less about injections. The abstracts of the small cream studies did not report harms, but the studies were too small to detect rare adverse effects [2, 3]A.
What users report. In the Reddit accounts we compiled (not research), 401 of 743 people (54%) reported some harm, most often: injection site pain, redness or lump (212, 29%), breakouts or purging (29, 4%) and fatigue (28, 4%). People tend to post when something goes wrong, so this share does not tell how common harms are. Most of those who said how they used it had injected GHK-Cu (383 people), so the figures in practice describe injections. Only 50 applied it to the skin, and some of them also injected, so the figures say little about creams and serums. The harms in detail: GHK-Cu user experiences.
Risks in injectable products
According to the FDA, injectable GHK-Cu preparations may pose a risk of immune reactions because the peptide can aggregate and products may contain peptide-related impurities. The FDA states that there are limited data in humans to inform safety [6]regulator.
According to Fimea, the possible harms or long-term effects of injectable products bought online may be unknown, and impurities such as endotoxins can cause serious harm to health [8]regulator.
What has not been studied
- Whether injected GHK-Cu is safe: there are few human data [6]regulator.
- Indications, dosing, frequency and duration of treatment for injected GHK-Cu are unknown [5].
More: Side effects and safety.
Interactions and who has no data
We found no research on interactions with other medicines. We found no clinical trials of injected GHK-Cu, so there are also no data for pregnancy or breastfeeding, children or people with chronic illness.
What speaks against it and what is unknown
Some human studies found no difference from placebo, and the independence of the evidence is weak [2, 3]A [4].
Contrary evidence
- In leg ulcers the 0.4% copper tripeptide cream did not shrink ulcers more than placebo cream, whereas silver sulfadiazine cream did [2]A.
- After laser treatment GHK-Cu products did not speed up the fading of redness or improve wrinkles according to evaluators; only patient satisfaction was higher [3]A.
- About 35% of original GHK-Cu studies from 2005-2026 list the researcher who isolated the peptide, or a researcher from his company, as an author [4].
What the evidence does not support
- "Cream studies apply to injections too": they do not. Human studies mainly concern creams [4], and we found no clinical trials of injected GHK-Cu.
- "GHK-Cu rejuvenates skin": in a small laser study evaluators saw no difference in wrinkle improvement [3]A, and the often-cited face cream studies are only conference abstracts [4].
- "Helps joint and tendon problems": there is no clinical study supporting this [5].
GHK-Cu dosage in studies
There is no approved dosage, because GHK-Cu is not a medicine [7]regulator. In human studies it was applied to the skin as a cream or gel. There is no study-based dose for injected GHK-Cu [5].
| Study | Who | Dose and route | Duration |
|---|---|---|---|
| Leg ulcers (1992) | 86 people with venous leg ulcers, three groups | cream with 0.4% copper tripeptide, on the ulcer | not stated in the abstract [2]A |
| Foot ulcers (1994) | people with diabetes and a neuropathic foot ulcer | metered dose of gel on the ulcer daily; concentration not stated in the abstract | not stated in the abstract [10]A |
| Cell culture (1988) | connective tissue cells, not humans | concentrations of 10⁻¹²-10⁻⁹ M (picomolar to nanomolar) in the culture | laboratory experiment [1]D |
What the numbers do not tell you. A cream concentration says nothing about an injection, and a cell culture concentration is not a human dose. The numbers are not recommendations. More detail: GHK-Cu doses in studies. The calculator does not open with GHK-Cu preselected, because there is no human study dose for the injectable form; the general calculator's list includes GHK-Cu only to fill in a vial size: Calculator.
GHK-Cu cream vs GHK-Cu injection: what is the difference?
They are different things: human studies mainly concern creams applied to the skin [4], and we found no clinical trials of injected GHK-Cu.
- Evidence: creams have small randomised trials with mixed results [2, 3, 10]A. For injections we found none.
- Safety: according to the FDA the injectable form carries a risk of immune reactions, and there are few human data [6]regulator.
- Status in Finland: according to Fimea, a product injected through the skin may be a medicine in Finland [8]regulator.
Combinations and blends
Combinations have not been studied in humans. Sellers declare GHK-Cu as a component of the Glow blend sold online, together with BPC-157 and TB-500. The declared composition has not been independently tested, and research on single substances is not research on the blend. More: Peptide blends: what is in the vial and why the seller's label is not enough and all blends.
Status in the United States
In the United States, injectable GHK-Cu has been among the FDA category 2 substances, meaning substances nominated for pharmacy compounding that may present significant safety risks. The nominator later withdrew the nomination. The FDA risk assessment is on its page (updated 22 Apr 2026) [6]regulator.
Is GHK-Cu legal in Finland?
GHK-Cu is listed in Annex 1 A of Fimea's medicines list [9]regulator. Annex 1 A substances are controlled as medicines in Finland and are always treated like prescription-only medicines. GHK-Cu has no marketing authorisation as a medicine [7]regulator. According to the medicines list, not every product containing a listed substance is necessarily a medicine: the assessment depends on things such as how the product is presented, its composition and how it is used [9]regulator. Skin creams are sold as cosmetics.
- Medicines list. In the Finnish medicines list (230/2025) GHK-Cu is named in annex 1 A, which covers medicinal substance analogues and prohormones classified as medicines [9]regulator.
- Marketing authorisation. On 15 Sep 2026 the EMA list contained no product with GHK-Cu as the active substance [7]regulator.
- Fimea warning, 29 Jun 2026. Fimea warned about injectable peptides bought online or through social media. According to Fimea, a product injected through the skin may be a medicine in Finland, and a "for research use only" label means the product is not intended for humans [8]regulator.
- Import. Ordering medicines from outside the EU is covered on Peptides and the law in Finland. Bringing them back from travel: Travelling with peptides.
This is not legal advice. Disclaimer.
Is GHK-Cu a doping substance?
The Prohibited List does not name GHK-Cu. Class S0 of the WADA 2026 list prohibits at all times substances not covered by the other classes and with no approval by any government health authority for human therapeutic use [11]regulator. GHK-Cu has no marketing authorisation as a medicine in the EU [7]regulator. Athletes should check with their national anti-doping organisation (in Finland, the Finnish Center for Integrity in Sports, SUEK).
How is a GHK-Cu product assessed?
You cannot be sure what an injectable product contains. According to Fimea, an unauthorised product may contain a different substance than the label says, and there is no reliable information on the content, quality and safety of research chemicals sold as peptides [8]regulator.
For GHK-Cu the FDA highlights peptide aggregation and peptide-related impurities [6]regulator. A seller's own certificate of analysis (COA) does not by itself show that a product is pure, sterile or free of endotoxin. For a certificate even to describe the content, it would need to identify the substance by mass spectrometry (MS), state the amount and purity, and refer to the same batch as the vial. More: How to read a COA and check a test result. Handling: Mixing and handling.
FAQ
What is GHK-Cu?
A three-amino-acid peptide (glycyl-histidyl-lysine) bound to a copper ion. It is used in cosmetic skin creams [1]D [4].
Is GHK-Cu an approved medicine?
No. The EMA list contains no authorised medicine containing GHK-Cu [7]regulator.
Does copper peptide work on skin?
Not known for sure. The evidence is small and mixed: in diabetic foot ulcers the gel helped [10]A, in leg ulcers the cream did not differ from placebo cream [2]A, and in a laser study evaluators saw no difference although patients were more satisfied [3]A.
Is a GHK-Cu cream the same as a GHK-Cu injection?
No. Human studies mainly concern creams [4], and we found no clinical trials of injected GHK-Cu.
GHK-Cu side effects: are injections safe?
Not known. The FDA says there are limited human data, and the injectable form carries a risk of immune reactions [6]regulator.
GHK-Cu dosage: is there a studied dose for injections?
No. According to a review, dosing and treatment duration for injected GHK-Cu are unknown [5]. Cream concentrations used in studies: GHK-Cu dosage in studies.
GHK-Cu in Finland: is it legal?
GHK-Cu is in Annex 1 A of the Finnish medicines list, whose substances are always treated like prescription-only medicines, but not every product containing it, such as a cosmetic cream, is necessarily a medicine [9]regulator. Fimea warns against injectable peptides bought online [8]regulator. This is not legal advice.
What does "for research use only" mean?
According to Fimea it means the product is not intended for humans [8]regulator.
What do users themselves report about GHK-Cu?
In the Reddit accounts of 743 people we compiled (not research), 369 (50%) reported some benefit and 401 (54%) some harm. The accounts are self-selected and prove neither that it works nor that it is safe: GHK-Cu user experiences.
Read the research yourself: sources
Every source opens the original publication or the regulator's page. The level shows what the source itself reports.
- 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;238:343-6. PMID 3169264 D
- Bishop JB, Phillips LG, Mustoe TA, et al. A prospective randomized evaluator-blinded trial of two potential wound healing agents for the treatment of venous stasis ulcers. J Vasc Surg. 1992;16:251-7. PMID 1495150 A
- Miller TR, Wagner JD, Baack BR, et al. Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin. Arch Facial Plast Surg. 2006;8:252-9. PMID 16847171 A
- Najafi N, Maatouk H, Vardanyan KG, et al. A Systematic Review of the Mechanisms and Therapeutic Applications of GHK-Cu in Topical Microneedle Delivery: A Case for Expanded Clinical Trials. Arch Intern Med Res. 2026;9:269-293. PMID 42787770 (review)
- Mayfield CK, Bolia IK, Feingold CL, et al. Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians. Am J Sports Med. 2026;54:223-229. PMID 41476424 (review)
- U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of 22 Apr 2026). FDA regulator
- European Medicines Agency. Medicine data (centrally authorised medicines, data set of 15 Sep 2026): no product with GHK-Cu as active substance. EMA regulator
- Fimea. Fimea varoittaa: älä käytä verkosta ostettuja pistettäviä peptidejä / Fimea warns: do not use injectable peptides purchased online. 29 Jun 2026. Fimea regulator
- Finland. Lääkeluettelo (Fimea medicines list), 230/2025, annex 1 A. Finlex regulator
- Mulder GD, Patt LM, Sanders L, et al. Enhanced healing of ulcers in patients with diabetes by topical treatment with glycyl-l-histidyl-l-lysine copper. Wound Repair Regen. 1994;2:259-69. PMID 17147644 A
- World Anti-Doping Agency. The 2026 Prohibited List, class S0 Non-approved substances (in effect from 1 Jan 2026). WADA regulator
Research sources checked 9-13 Oct 2026. Regulator and registry sources checked 15 Sep to 13 Oct 2026.
Evidence levels: A = randomised human trial or meta-analysis · B = observational human study or case series · C = animal study · D = cell or laboratory study · E = not peer-reviewed · regulator = a regulator's assessment or decision, not research evidence. The marker official means official product information (summary of product characteristics or label); it is not research evidence. For a review, the level shows what kind of research the statement rests on. No level: statements that something has not been studied, reviews' interpretations, named hypotheses and the general rules in our certificate-of-analysis guide.
Content is general information about research, not medical advice. If you have symptoms, contact a healthcare professional.