GHK-Cu

A reference work, not a recommendation to use: this profile describes mechanism and evidence and does not replace medical advice. The claims come from marketing and forums and are tested here, not endorsed.

Claims checked

• Skin rejuvenation: fewer wrinkles, firmer skin

  Mixed results

  Recovery & healing · healthy · Human, randomised

  After laser treatment, no objective benefit in 13 people ^[7]. A systematic review reports reduced wrinkle volume and depth from a second randomized study ^[8]. Other frequently cited facial studies are small or appeared only as conference contributions, in part from the discoverers' own group ^[1][9].^[1][9]

• More hair growth

  Single unconfirmed finding

  Recovery & healing · healthy · Human, randomised small studiesEvery study behind this level and result had fewer than 100 participants. Small studies report larger effects on average than large ones, so the result is less certain.

  A randomized eyebrow study with 18 people reported more and thicker hair, published outside PubMed, product not chemically characterized ^[9]. The follicle study tested the related AHK-Cu, not GHK-Cu ^[4]. No study of scalp hair loss was found.

• Wounds heal faster

  Single unconfirmed finding

  Recovery & healing · Patients: diabetic foot ulcers · Human, randomised

  A randomized, observer-blinded study from 1994 found greater wound closure and fewer infections ^[6]; confirmation by later studies was not found.

• Rejuvenates the whole body and resets genes (injection)

  Not studied

  Longevity · healthy · Laboratory

  The basis is gene expression analyses done by computer and in cells ^[1][3]. There is no study of systemic administration in humans ^[9][10].^{[1][3][9][10]}

Mechanism of action

GHK (glycyl-histidyl-lysine) occurs in blood plasma, saliva, and urine. According to the research group around Loren Pickart, who described the peptide in 1973, the plasma level falls from about 200 ng/ml at age 20 to 80 ng/ml at age 60; the same review, written at a skin care company, credits GHK with “resetting” at least 4000 genes “to a healthier state” ^[1]. What is established is an early laboratory effect: in fibroblast cultures, GHK-Cu increased collagen synthesis from 10⁻¹² to 10⁻¹¹ M, with a maximum at 10⁻⁹ M, without changing cell numbers ^[2]. The gene claim goes back to a study of lung tissue from people with COPD: using the Connectivity Map database, GHK was identified as a compound that reverses the gene expression pattern of emphysema-related destruction; in fibroblasts from COPD lungs, GHK restored collagen contraction ^[3]. This is a computational and cell-based finding, not evidence of rejuvenation in the body.

For hair growth, a Korean study is often cited, but it tested the related copper peptide AHK-Cu: it lengthened isolated human hair follicles and promoted division of papilla cells ^[4]. In the laboratory, copper from GHK-Cu passed through isolated human skin in measurable amounts ^[5]; this does not show whether intact GHK-Cu reaches the deeper skin layers. For copper as a nutrient and its forms, see the Copper profile.

In humans there are few controlled studies. In a randomized, observer-blinded study in diabetic foot ulcers, a GHK-Cu gel closed the wounds more than the vehicle (median area reduction 98.5% versus 60.8%), with fewer infections ^[6]. After CO2 laser treatment of facial skin, blinded assessors found no objective benefit for wrinkles, redness, or skin quality in 13 people; only satisfaction was higher ^[7]. A systematic review from 2026 found 18 preclinical studies and only 2 randomized studies for aesthetic uses ^[8]. A critical review from the same year rates the clinical evidence as sparse: the frequently cited facial studies are small or published only as conference contributions, an eyebrow study with 18 people was positive, and almost no study describes the actual copper binding of the product ^[9]. For injections of the kind offered on the gray market, reliable safety data in humans are lacking ^[10].

Targets

Effect profile

Which signaling systems the compound affects according to current data. ↑ enhanced, ↓ dampened, ≈ modulated, ○ no effect; dots = evidence level.

• ·Dopamineno data
• ·Noradrenalineno data
• ·Serotoninno data
• ·Acetylcholineno data
• ·Glutamate · AMPAno data
• ·Glutamate · NMDAno data
• ·GABAno data
• ·Histamineno data
• ·Orexinno data
• ·Adenosineno data
• ·Opioidsno data
• ·Melatoninno data
• ·Neurotrophinsno data
• ↑Blood flow↑ · new blood vessel formation in wound and biomaterial models (animal, laboratory)^[9]
• ·Nitric oxideno data
• ·Energy metabolismno data
• ·Insulin · glucoseno data
• ↓Inflammation · oxidative↓ · anti-inflammatory and antioxidant effects in cell and animal models; not demonstrated clinically^[9]
• ·Stress axisno data
• ·Testosterone axisno data
• ·Endocannabinoidsno data
• ·Autophagy · senescenceno data
• ·Immune systemno data
• ·Lipid metabolismno data
• ·Coagulation · fibrinolysisno data
• ·Methylationno data

Routes of administration and bioavailability

How much of a compound reaches the blood or target tissue depends on the route into the body and on the dosage form. All routes of administration explained

• Transdermal (through the skin) · Cream, serum, gel

  In the laboratory, copper from GHK-Cu passed through isolated human skin ^[5]; microneedles and liposomes improved uptake into the skin in studies ^[8]. How much intact GHK-Cu reaches the target layer has hardly been studied ^[9].

  Laboratory

• Subcutaneous (under the skin) · Injection (gray market)

  No published human study found; reliable safety data are lacking ^[10]. A review calls for dedicated testing of injectable preparations, including for free copper and allergies ^[9].

  No data

Human studies

• GHK-Cu gel in diabetic foot ulcers

  multicenter, randomized, observer-blinded, vehicle-controlled · Patients: diabetic neuropathic ulcers · not verified

  Measured: percent wound closure, proportion with at least 98% healing, infections

  Result: Median area reduction 98.5% versus 60.8% with vehicle; infections 7% versus 34%. Number of participants not given in the abstract.^[6]

  Human, randomised

• Skin care with GHK-Cu after CO2 laser treatment

  randomized, blinded assessment · Patients: laser treatment of the skin around the mouth · n = 13 · 12 weeks

  Measured: redness (computer analysis, blinded assessment), wrinkles, skin quality, questionnaire

  Result: No objective difference in redness, wrinkles, or skin quality; higher satisfaction with GHK-Cu.^[7]

  Human, randomised

Risks and warnings

• No safety data on injections

  For injections offered on the gray market, reliable safety data in humans are lacking ^[10].

  No data

• Unclear composition

  Copper binding, the proportion of free copper, and purity are mostly not stated for GHK-Cu products; efficacy and tolerability may depend on them ^[9].

  No data

• Contact allergy to copper

  Copper is a known contact allergen in sensitive people; exposure rises with broken skin or injection ^[9].

  No data

• Theoretical: new blood vessel formation at an unwanted site

  The vessel-promoting effect is desirable in wounds but could be unfavorable in tumors or pathological vessel growth in the eye; data on this are lacking ^[9].

  No data

Fact check: common claims

• partly supported

  “GHK-Cu makes wrinkles disappear”

  One randomized study reported reduced wrinkle volume ^[8], another found no objective benefit ^[7]; many facial studies are small or published only as conference contributions ^[9].

• not supported

  “GHK resets over 4000 genes to a young state”

  The claim comes from a review by the discoverers' group ^[1] and rests on gene expression databases and cell experiments ^[3]; rejuvenation in the body has never been measured.

• not supported

  “GHK-Cu injections rejuvenate the whole body”

  No human study with systemic administration ^[9]; safety data are lacking ^[10].

• not supported

  “GHK-Cu helps against hair loss”

  Only one small eyebrow study ^[9] and a follicle study with the related AHK-Cu ^[4]; no study of scalp hair loss.

Pharmacokinetics

Absorption

Topical: limited skin passage measurable in the laboratory ^[5]. Systemic absorption not studied in humans.

Half-life

Not measured; a short half-life is expected for free GHK because of peptidases ^[9].

Metabolism

Expected breakdown to glycine, histidyl-lysine, and amino acids; released copper is bound to albumin, histidine, and ceruloplasmin ^[9].

Entry into the brain

Not studied.

Legal status

Germany

Widely used as a cosmetic ingredient ^[1]; no marketing authorization known, not checked in registers.

EU

No marketing authorization known; not verified.

USA

No marketing authorization known; not verified. Marketed directly to patients alongside other unapproved peptides ^[10].

Related compounds

complex

one of the two substances is a defined complex containing the other as central atom or component

Open questions

• How much intact GHK-Cu reaches the dermis after topical use?
• Do larger, independent, vehicle-controlled studies with chemically characterized products confirm the effect on wrinkles?
• What happens to the peptide and copper after injection, and is it safe?