GHK-Cu Evidence: Topical vs Injected and the 31.2% Gene Claim

Key points

• Every controlled human study of GHK-Cu we could read tested a cream, serum or gel on skin. Where stated, they enrolled 13 to 40 people for 8 to 16 weeks [5][6][8][9].
• We found no published human study and no registered trial of injected GHK-Cu. FDA says there are “limited data in humans” for the injectable route [16].
• The “31.2% of the genome” figure comes from a 2014 analysis of three profiles from two cancer cell lines. It counts genes changed up or down by at least 50%, not genes “upregulated” [2].
• GHK-Cu is a cosmetic ingredient in the EU and US; we found no approved medicine containing it. FDA lists the injectable route among withdrawn compounding nominations, citing immunogenicity [16][23].

What GHK-Cu is and where it came from

GHK is the tripeptide glycyl-L-histidyl-L-lysine. GHK-Cu is its copper(II) complex, listed in cosmetics as copper tripeptide-1 [20]. It is one of the compounds we compare on Peptilyze (/compounds/ghk-cu/); this article covers evidence only.

Loren Pickart and M. M. Thaler reported a tripeptide in human serum in 1973, in a paper titled “Tripeptide in human serum which prolongs survival of normal liver cells and stimulates growth in neoplastic liver” [3]. A 1980 Nature paper by Pickart and colleagues found it co-isolated with roughly equal amounts of copper and proposed it helps move copper into cells [4]. A 2026 systematic review estimates that about 35% of GHK-Cu primary papers in its window include Pickart or co-author Anna Margolina, and says Pickart held commercial interests in the field for decades [12]. Their papers list Skin Biology (Bellevue, Washington) as affiliation and declare no conflict of interest [1][2].

What the human studies show

We opened five human studies. The table gives design, size and funding as stated in each paper.

Study	Design	Size and length	Reported result	Funding
Mulder 1994 [7]	Multicenter, randomized, evaluator-blinded, vehicle-controlled; diabetic foot ulcers (wound gel)	Not in abstract	Median ulcer closure 98.5% vs 60.8% vehicle (p < 0.05)	Could not verify
Miller 2006 [6]	Randomized, blinded evaluators; with or without GHK-Cu after CO2 laser resurfacing	13 completed; 12 weeks	No objective difference in redness, wrinkles or skin quality; questionnaire favoured GHK-Cu (P = .04)	Could not verify
Badenhorst 2016 [5]	Randomized, double-blind, split-face; nano-carrier GHK-Cu serum vs a Matrixyl 3000 product or a vehicle lacking GHK-Cu and carrier	40 women, 40 to 65; 8 weeks	Wrinkle volume 31.6% lower than the Matrixyl product (p = 0.004); volume 55.8% and depth 32.8% lower than control	Snowberry New Zealand Ltd (supplied the serum) with Callaghan Innovation
Bo 2026 [8]	Randomized, double-blind, vehicle-controlled, split-face; eyebrow hair	18 adults; 12 weeks	Hair count rose on treated side; not significantly on placebo side	Not shown
Vignesh 2026 [9]	Not randomized, no blinding described; acne scars, needling with or without GHK-Cu	40 patients; 16 weeks	Differences to week 3 only; hyperpigmentation in 8 of 20 with GHK-Cu, none in the other group	“Nil”

Four of the five were randomized and had some blinding (Mulder, Miller, Badenhorst, Bo); Vignesh was neither. Where length is stated, none of the four ran past 12 weeks, and only Badenhorst states an industry funder. Badenhorst measured one wrinkle per volunteer, near the corner of the eye [5].

Other evidence is outside what we could check. Pickart and Margolina cite two 2002 meeting abstracts (71 women with a facial cream, 41 with an eye cream, 12 weeks each), a 1998 comparison with vitamin C and tretinoin, and a German pilot study [1]. We could not open them; a 2026 review says the 2002 reports exist only as abstracts [12]. A Phase 2 randomized, vehicle-controlled gel trial on small standardized wounds (NCT07437586, 60 planned participants, sponsor Hudson Biotech) was recruiting on 2026-11-08 and has no results [10]. A 2026 evidence map calls the clinical evidence “sparse” [11].

Is there human evidence for injection or systemic use?

We found none. Title and abstract searches of Europe PMC [25] and ClinicalTrials.gov on 2026-11-08 turned up no human study in which GHK-Cu was injected. The one registered trial testing GHK-Cu itself that we found is the topical wound gel [10].

FDA cites “limited data in humans to inform safety-related considerations” [16]. A 2026 evidence map says human pharmacokinetics, biodistribution and repeat-dose toxicology “remain absent” [11].

Animal and cell work, kept separate

• Cell culture. In cultured human dermal fibroblasts, nanomolar GHK-Cu increased collagen and elastin production [5].
• Animals. In a 1993 rat study, GHK-Cu injected into an implanted wound chamber increased connective-tissue accumulation versus saline [13]. In experimental silicosis, a defined GHK-Cu preparation given systemically reduced lung inflammation and fibrosis without significant systemic toxicity [11].

Neither establishes a dose, benefit or safety margin in people.

Where the “31.2% of the genome” figure comes from

The tier-list post says GHK-Cu “upregulates human genes across 31.2% of the genome” [24]. The number traces to Pickart’s group.

Source. The 2018 review states that the share of human genes “stimulated or suppressed” by GHK at a change of 50% or more is 31.2%, with 59% increased and 41% suppressed [1]. The analysis itself is in a 2014 paper, “GHK and DNA: Resetting the Human Genome to Health” [2].

Data. The authors used Broad Institute Connectivity Map profiles retrieved on 5 March 2013: three GHK profiles on one microarray type, two in PC3 (prostate cancer) cells and one in MCF7 (breast cancer) cells, which are 2 of the map’s 5 cell lines [2]. No skin cells are in the dataset. Probe-level changes were averaged per gene, mapping 22,277 probe sets to 13,424 genes [2]. The passages we read describe a fold-change cutoff, not replicate arrays or a significance test, and give no concentration or exposure time [2].

“Modulates” versus “upregulates”. The figure counts movement in either direction. On the authors’ own 59/41 split, upregulated genes would be about 18% of the total (our arithmetic). The 2018 table’s rows add up to 4,200 genes, 2,687 of them stimulated (64%), which does not match 59% (our arithmetic; the paper does not explain the gap) [1]. The 2014 introduction gives 32.1% for the same analysis and its methods give 31.2% [2].

Replication. We found no independent replication of the 31.2% count. A separate group (Campbell and colleagues) used the Connectivity Map in 2012 to find GHK reversing a lung-emphysema signature and confirmed selected effects in human fibroblasts [14]; that supports a narrower finding. A 2026 review calls broad “gene-resetting” claims hypothesis-generating and notes such work often involves GHK without copper, or computational signatures [11].

mRNA changes in cancer cell lines do not show what a cream does in skin. Our claim check on the 31.2% figure goes further.

Regulatory status

Cosmetic use. In the US, cosmetics and their ingredients need no FDA premarket approval (colour additives aside), and a product intended to treat or prevent disease is a drug [19]. The Cosmetic Ingredient Review Expert Panel judged copper tripeptide-1 safe in cosmetics at present practices of use, with typical concentrations below 10 ppm [20]. In the EU, a product may be sold as a cosmetic if its claims stay within the cosmetic definition and it meets Regulation (EC) No 1223/2009; that is not therapeutic approval [11]. We did not open the EU CosIng record.

Medicines. A query of openFDA’s Drugs@FDA endpoint on 2026-11-08 for GHK, copper tripeptide and the full peptide name returned no matches [23]. We could not check EMA, BfArM or MHRA registers.

US compounding. Category 2 of FDA’s bulk-substance categories means FDA found significant safety risks pending evaluation and does not apply its category 1 policy [17]. FDA’s safety-risk page (current as of 22 April 2026) lists “GHK-Cu (for injectable routes of administration)” in a table of nominated-but-withdrawn substances, previously in category 2, and says compounded injectables “may pose risk for immunogenicity” through aggregation and peptide-related impurities [16]. FDA’s category document (updated 14 May 2026) says GHK-Cu left category 1 on 22 April 2026 when nominations were withdrawn; on 5 May a nominator said it withdrew only the injectable route. GHK-Cu “except for injectable routes” is to return to category 1, titled “Under Evaluation”, and FDA intends to consult its Pharmacy Compounding Advisory Committee before the end of February 2027 [15].

In plain terms: the injectable route is not in category 1 there, FDA has recorded a safety concern for it, and none of this approves any route. We found no later update.

“Research use only.” This is a seller’s label, not a regulatory category. In a 31 March 2026 warning letter to Gram Peptides (which does not name GHK-Cu), FDA said such labels do not settle the matter and that website evidence showed the products were intended as human drugs [18].

Risks and unknowns

• Topical tolerability. One of 40 volunteers had a minor skin reaction that resolved [5]. In the non-randomized acne-scar study, 8 of 20 in the GHK-Cu group developed hyperpigmentation, none in the comparison group [9]. The longest human study we read ran 16 weeks [9].
• Copper. EFSA concluded no copper retention is expected at 5 mg a day orally in adults; the US adult upper intake level is 10 mg a day. A 2026 review says these dietary values cannot be converted into limits for injection, and that absorption and elimination of the intact complex have not been formally reported [11].
• Immunogenicity and impurities. FDA flags both for injectable GHK-Cu [16].
• Growth and blood vessels. GHK-containing materials have been linked to new vessel growth in repair models, which the 2026 evidence map says may be undesirable in tumours or vascular disease [11]. Pickart’s group reports anti-cancer gene effects in cells [1]; the 1973 paper’s title reports growth stimulation of neoplastic liver cells [3]. This is unresolved.
• Unregulated product quality. A 2026 preprint (not peer reviewed) analysed 6,441 gray-market peptide samples across 14 compounds, GHK-Cu among them. Between 41.6% and 71.1% failed basic quality criteria depending on the standard, and 15% had measurable endotoxin. The abstract gives no GHK-Cu-only result [22].
• Not studied. Human repeat-dose toxicology, pharmacokinetics and interactions are absent from the sources we read [11]. A 2026 sports-medicine review says rigorous human safety data are scarce for unapproved peptides generally [21].

What the source posts claim, and how it holds up

The posts come from one account; tier-list placement is opinion and cites no evidence [24].

Claim	Verdict	Basis
GHK-Cu “upregulates human genes across 31.2% of the genome”	Not supported as worded	Counts genes moved up or down by at least 50% in cancer cell-line data [1][2]
Provides “collagen, elastin & glycosaminoglycan synthesis”	Partly supported	Shown in cultured fibroblasts [5]; human skin reports are among papers we could not open [1]
“Best combined with microneedling”	Not supported by what we found	One non-randomized study of 40 people: early differences only, more hyperpigmentation [9]
Topical ranked high, injected ranked low	Ranking is opinion	All controlled human data we found are topical; none for injection [5][6][8][16]

Frequently asked questions

Does topical GHK-Cu reduce wrinkles in humans? One 8-week, 40-person randomized trial, funded by the company that supplied the serum, reported lower wrinkle volume than a vehicle and a competitor product [5]. A 13-person trial after laser resurfacing found no objective difference [6].

Has injected GHK-Cu been tested in people? We found no published human study and no registered trial. FDA calls human data for the injectable route limited and records an immunogenicity concern [16].

Does GHK-Cu change 31.2% of human genes? That number comes from a 2014 analysis of three cancer-cell-line profiles and counts genes moving up or down by at least 50% [2]. We found no independent replication.

Is GHK-Cu approved by the FDA? We found no approved medicine containing it [23]. It is sold in cosmetics, which need no premarket approval [19]. Injectable compounding status is described above [15][16].

Sources

1. Pickart L, Margolina A, “Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data”, Int J Mol Sci (2018-07-07). https://pmc.ncbi.nlm.nih.gov/articles/PMC6073405/ (DOI 10.3390/ijms19071987; full text read via Europe PMC).
2. Pickart L, Vasquez-Soltero JM, Margolina A, “GHK and DNA: Resetting the Human Genome to Health”, BioMed Res Int (2014). https://pmc.ncbi.nlm.nih.gov/articles/PMC4180391/
3. Pickart L, Thaler MM, “Tripeptide in human serum which prolongs survival of normal liver cells and stimulates growth in neoplastic liver”, Nature New Biology (1973). https://europepmc.org/article/MED/4349963 (title and authors only; no abstract available).
4. Pickart L et al., “Growth-modulating plasma tripeptide may function by facilitating copper uptake into cells”, Nature (1980). https://europepmc.org/article/MED/7453802 (abstract).
5. Badenhorst T et al., “Effects of GHK-Cu on MMP and TIMP Expression, Collagen and Elastin Production, and Facial Wrinkle Parameters”, J Aging Sci (2016-12-22). https://doi.org/10.4172/2329-8847.1000166
6. Miller TR et al., “Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin”, Arch Facial Plast Surg (2006). https://europepmc.org/article/MED/16847171 (abstract only).
7. Mulder GD et al., “Enhanced healing of ulcers in patients with diabetes by topical treatment with glycyl-L-histidyl-L-lysine copper”, Wound Repair Regen (1994). https://europepmc.org/article/MED/17147644 (abstract only).
8. Bo SL et al., “The Efficacy of 2% Copper Peptide (GHK-Cu) Serum for Eyebrow Hypotrichosis”, Procedia Multidiscip Res (2026-05-22). https://so09.tci-thaijo.org/index.php/PMR/article/view/9318 (abstract page only).
9. Vignesh NR et al., “A study comparing the effect of dermaroller versus dermaroller with copper peptide in the management of acne scars”, J Cutan Aesthet Surg (2026). https://doi.org/10.25259/JCAS_56_2025
10. ClinicalTrials.gov, NCT07437586, “Topical GHK-Cu Gel for Acute Skin Wound Healing” (queried 2026-11-08). https://clinicaltrials.gov/study/NCT07437586
11. Mateescu DM et al., “GHK-Cu as a Bioactive Metallopeptide and Drug-Delivery Cargo”, Pharmaceutics (2026). https://pmc.ncbi.nlm.nih.gov/articles/PMC13610439/
12. Najafi N et al., “A Systematic Review of the Mechanisms and Therapeutic Applications of GHK-Cu in Topical Microneedle Delivery”, Arch Intern Med Res (2026). https://pmc.ncbi.nlm.nih.gov/articles/PMC13604022/ (secondary; used only for statements consistent with primary sources).
13. Maquart FX 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). https://europepmc.org/article/MED/8227353 (abstract only).
14. Campbell JD et al., “A gene expression signature of emphysema-related lung destruction and its reversal by the tripeptide GHK”, Genome Med (2012). https://pmc.ncbi.nlm.nih.gov/articles/PMC4064320/
15. FDA, “Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the FD&C Act” (updated 2026-05-14). https://www.fda.gov/media/94155/download
16. FDA, “Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks” (content current as of 2026-04-22). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
17. FDA, “Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act” (content current as of 2026-05-14). https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act
18. FDA, Warning Letter to Gram Peptides, 721806 (2026-03-31). https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/gram-peptides-721806-03312026
19. FDA, “FDA Authority Over Cosmetics: How Cosmetics Are Not FDA-Approved, but Are FDA-Regulated” (content current as of 2025-11-18). https://www.fda.gov/cosmetics/cosmetics-laws-regulations/fda-authority-over-cosmetics-how-cosmetics-are-not-fda-approved-are-fda-regulated
20. Johnson W et al. (Cosmetic Ingredient Review Expert Panel), “Safety Assessment of Tripeptide-1, Hexapeptide-12, Their Metal Salts and Fatty Acyl Derivatives, and Palmitoyl Tetrapeptide-7 as Used in Cosmetics”, Int J Toxicol 37(3_suppl):90S-102S (2018-11). https://pure.psu.edu/en/publications/safety-assessment-of-tripeptide-1-hexapeptide-12-their-metal-salt/ (abstract page; DOI 10.1177/1091581818807863).
21. Mendias CL, Awan TM, “Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance”, Sports Med (2026). https://doi.org/10.1007/s40279-026-02437-0 (abstract only).
22. Mendias CL, Awan TM, “Evaluation of Research Grade Peptides Marketed Directly to Consumers Reveals Extensive Variability in Purity and Measured Abundance”, Preprints.org, not peer reviewed (2026-04-24). https://doi.org/10.20944/preprints202604.1748.v1 (abstract only).
23. openFDA, Drugs@FDA endpoint query for GHK, copper tripeptide and glycyl-l-histidyl-l-lysine (queried 2026-11-08). https://api.fda.gov/drug/drugsfda.json
24. @Hoostethics, posts of 2026-10-15, 2026-10-22 and 2026-11-01 (a supplement tier list, a looksmaxxing tier list and a skincare post), read through the fxtwitter mirror; tier placements read from the images. https://x.com/Hoostethics/status/2110728908735979632 ; https://x.com/Hoostethics/status/2113302148750758106 ; https://x.com/Hoostethics/status/2116976569034092805 . Claims, not evidence.
25. Europe PMC search (title and abstract queries for GHK-Cu with injection, case report, adverse event and clinical-trial terms, run 2026-11-08). https://europepmc.org

This article is information, not medical advice.