{
  "ingredient": "GHK-Cu / Copper Tripeptide-1",
  "scope": "Topical cosmetic evidence; selected reports, not an exhaustive trial count.",
  "studies": [
    {
      "id": "eye2002",
      "category": "human",
      "title": "Eye-area appearance: a 12-week report",
      "citation": "Leyden, Stephens, Finkey & Barkovic, AAD meeting proceedings, 2002; summarized in the 2025 review, reference 15.",
      "access": "Secondary report \u00b7 original not verified",
      "design": "Topical eye-cream comparison; randomization, masking and group allocation not established from the review.",
      "population": "41 women with mild to advanced photodamage; group sizes not provided.",
      "dose": "GHK-Cu-containing eye cream; concentration, amount and application frequency not reported in the retrieved review.",
      "duration": "12 weeks",
      "endpoint": "Lines and wrinkles around the eyes; skin thickness and density.",
      "result": "The review reports improved appearance, fewer lines and wrinkles, and greater thickness and density compared with placebo or a vitamin K cream. Numerical changes and uncertainty are not supplied.",
      "limit": "Conference-level source. Without the original methods and results, the size and reliability of the benefit cannot be checked. This is not a trial of a current Neurogan eye or face product.",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/",
      "signal": "Favorable, low-certainty report"
    },
    {
      "id": "face2002",
      "category": "human",
      "title": "Facial photoaging: a second 12-week report",
      "citation": "Leyden, Stephens, Finkey, Appa & Barkovic, AAD meeting proceedings, 2002; summarized in the 2025 review, reference 16.",
      "access": "Secondary report \u00b7 original not verified",
      "design": "Topical facial-cream study; control, randomization and masking not adequately described in the retrieved review.",
      "population": "71 women with mild to advanced facial photodamage; group sizes not given.",
      "dose": "GHK-Cu-containing cream; concentration and application amount/frequency not stated.",
      "duration": "12 weeks",
      "endpoint": "Skin density, thickness, laxity, fine lines and wrinkle depth.",
      "result": "The review reports increased skin density and thickness and reduced laxity, fine lines and wrinkle depth. It does not provide a numerical effect size, confidence interval or enough comparator data to reconstruct the result.",
      "limit": "A separate conference report, not a verified full randomized-trial publication. Repetition in later reviews does not add new participants or independent confirmation.",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/",
      "signal": "Favorable, low-certainty report"
    },
    {
      "id": "biopsy1998",
      "category": "human",
      "title": "The \u201c70%\u201d result was a biopsy response, not wrinkle reduction",
      "citation": "Abdulghani et al., pilot study cited as 1998 in the 2025 review, reference 14.",
      "access": "Secondary report \u00b7 original not verified",
      "design": "One-month pilot with paired thigh applications. Ten participants used copper-peptide and melatonin creams on opposite thighs; ten others used vitamin C and retinoic acid creams.",
      "population": "20 participants in total; only 10 received the copper-peptide cream.",
      "dose": "Topical cream identified as GHK-Cu by the review; concentration and application amount not reported.",
      "duration": "1 month",
      "endpoint": "Skin biopsy ultrastructure and procollagen synthesis by dermal papillary fibroblasts.",
      "result": "The review reports increased procollagen synthesis in 70% of the copper-peptide group, versus 50% of the vitamin C group and 40% of the retinoic acid group. These are proportions of participants showing a biopsy response, not the amount of new collagen or change in wrinkles.",
      "limit": "Tiny groups, thigh rather than facial skin, and a tissue marker rather than a visible cosmetic outcome. Comparator creams were used in different participant groups. The original paper and its bibliographic details were not independently verified.",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/",
      "signal": "Favorable tissue marker \u00b7 not visible efficacy"
    },
    {
      "id": "ferment2026",
      "category": "combination",
      "title": "A newer face-cream study tested a combination",
      "citation": "Wang, Tao, Huang & Chang. Skin Research and Technology, 2026;32(8). DOI: 10.1111/srt.70360. PMID: 42573538.",
      "access": "Primary publication \u00b7 abstract only",
      "design": "Laboratory, excised-skin and clinical testing of mixed-culture ferment extract plus GHK-Cu. Clinical allocation, masking and comparator are not stated in the abstract.",
      "population": "Clinical participant count, age range and skin types are not reported in the accessible abstract.",
      "dose": "Face cream with Thermus thermophilus/Bacillus subtilis mixed-culture ferment extract and GHK-Cu as the reported active combination; concentrations and application schedule unavailable.",
      "duration": "Clinical duration not reported in the accessible abstract.",
      "endpoint": "Clinical wrinkles and skin barrier conditions; separate laboratory inflammation and UV-exposed skin outcomes.",
      "result": "The abstract reports decreased wrinkles and improved skin barrier conditions in the clinical study. It gives no clinical numerical changes, group sizes, confidence intervals or p-values.",
      "limit": "This is direct clinical publication evidence for a combination, not GHK-Cu alone. Full text was not available for method verification. The formulation is not one of the Neurogan products compared below; laboratory comparisons cannot establish which ingredient drove the clinical finding.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/42573538/",
      "signal": "Favorable combination \u00b7 incomplete clinical detail"
    },
    {
      "id": "ha2023",
      "category": "laboratory",
      "title": "GHK-Cu + hyaluronic acid: a laboratory collagen signal",
      "citation": "Synergy of GHK-Cu and hyaluronic acid on collagen IV upregulation via fibroblast and ex-vivo skin tests. Journal of Cosmetic Dermatology, 2023. DOI: 10.1111/jocd.15763. PMID: 37062921.",
      "access": "Primary publication \u00b7 abstract only",
      "design": "Human dermal fibroblast testing followed by testing of a selected combination in excised human skin.",
      "population": "Cultured cells and skin outside the body, not treated volunteers. Donor and replicate counts not provided in the abstract.",
      "dose": "GHK-Cu to low-molecular-weight hyaluronic acid ratio of 1:9; absolute concentrations not stated in the abstract.",
      "duration": "Not stated in the abstract.",
      "endpoint": "Collagen I, IV and VII gene expression; collagen IV immunofluorescence in skin.",
      "result": "The selected combination reportedly increased collagen IV 25.4-fold in the cell test and 2.03-fold in the excised-skin test. The assays and tissue systems differ; these numbers are not interchangeable.",
      "limit": "Not a human wrinkle trial. A selected blend and HA molecular weight matter. Neither fold-change is a percentage reduction in wrinkles, and neither establishes a tested serum concentration.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/37062921/",
      "signal": "Favorable laboratory combination"
    },
    {
      "id": "delivery2011",
      "category": "laboratory",
      "title": "Skin delivery depends on the model, not just the molecule",
      "citation": "Hostynek, Dreher & Maibach. Human skin penetration of a copper tripeptide in vitro as a function of skin layer. Inflammation Research, 2011. DOI: 10.1007/s00011-010-0238-9. PMID: 20721598.",
      "access": "Primary publication \u00b7 abstract and review context",
      "design": "Flow-through diffusion cells containing isolated skin layers; copper measured in tissues and receiver fluid.",
      "population": "Excised human skin; not a clinical cosmetic study. Donor count not established from the abstract.",
      "dose": "0.68% aqueous copper tripeptide under infinite-dose laboratory conditions; 1 cm\u00b2 exposure area.",
      "duration": "48 hours",
      "endpoint": "Copper retention and permeation, measured by ICP-MS.",
      "result": "Copper was detected beyond dermatomed skin and retained within skin. The review reports very different permeation across isolated stratum corneum, epidermis and split-thickness skin.",
      "limit": "Delivery background only. An abundant laboratory dose is not a few drops of serum. Measuring elemental copper cannot show that intact GHK-Cu reached its target; copper can separate from GHK and bind other molecules. No wrinkle outcome was measured.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/20721598/",
      "signal": "Delivery demonstrated \u00b7 cosmetic effect untested"
    },
    {
      "id": "stability2014",
      "category": "laboratory",
      "title": "Some formulations preserve GHK-Cu better than others",
      "citation": "Badenhorst, Svirskis & Wu. Physicochemical characterization of native glycyl-L-histidyl-L-lysine tripeptide for wound healing and anti-aging: a preformulation study for dermal delivery. DOI: 10.3109/10837450.2014.979944. PMID: 25384620; online 2014.",
      "access": "Primary publication \u00b7 abstract only",
      "design": "Bench testing of solubility, distribution, stress degradation and compatibility with potential carrier ingredients.",
      "population": "Solutions and carrier systems; no human participants.",
      "dose": "Multiple laboratory conditions; no clinical application dose. Buffers spanning pH 4.5\u20137.4 were examined.",
      "duration": "At least 2 weeks for the reported water/buffer stability test at 60\u00b0C.",
      "endpoint": "Peptide concentration and degradation products, assessed using chromatography and mass spectrometry.",
      "result": "GHK-Cu was stable in the tested water and buffers but susceptible to basic and oxidative stress. It was compatible with Span 60-based niosomes and less stable with the negatively charged lipid dicetyl phosphate.",
      "limit": "A formulation test, not a human safety or efficacy trial. Accelerated conditions do not establish the shelf life of every finished product. These results also do not justify blanket rules about mixing all copper peptides with every other skincare active.",
      "url": "https://pubmed.ncbi.nlm.nih.gov/25384620/",
      "signal": "Mixed stability \u00b7 formula-specific"
    },
    {
      "id": "review2025",
      "category": "review",
      "title": "The review that traces the older cosmetic reports",
      "citation": "Topically applied GHK as an anti-wrinkle peptide: Advantages, problems and prospective. BioImpacts, 2025 collection. DOI: 10.34172/bi.30071. PMID: 39963574; PMC11830136.",
      "access": "Narrative review \u00b7 full text read",
      "design": "Narrative discussion of GHK, GHK-Cu, palmitoyl-GHK, activity, penetration and formulation.",
      "population": "Mixed laboratory literature and small human reports; no new participants and no pooled trial population.",
      "dose": "Varies across cited studies. The older cosmetic cream concentrations are not supplied.",
      "duration": "Varies; human reports summarized above last 1 month or 12 weeks.",
      "endpoint": "Biological activity, delivery and selected signs of skin aging.",
      "result": "The body describes small favorable human reports and extensive laboratory plausibility, while highlighting insufficient published permeability, effectiveness and safety information.",
      "limit": "Not a systematic review or meta-analysis. Its abstract refers to an absence of clinical studies despite describing human studies in the body. This page follows the actual cited reports and their availability rather than treating that wording as proof of either no research or strong efficacy.",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/",
      "signal": "Useful synthesis \u00b7 limited clinical foundation"
    }
  ]
}