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Healing & repair

GHK-Cu

Also known as: Copper tripeptide-1, GHK-copper, Glycyl-L-histidyl-L-lysine-copper(II), Cu-GHK, Lamin

GHK-Cu is the only peptide on this list with mainstream cosmetic adoption — three decades of topical RCTs in photoaged skin, paired with a deeper preclinical literature on tissue regeneration than is widely appreciated outside dermatology.
Primary sources
6

1 tier 1

Mechanism dossiers
21

19 decision

Documented cycles
4

Across all tiers

Last reviewed
2026-04-28
01·Mechanism

GHK is the tripeptide glycyl-L-histidyl-L-lysine, originally isolated from human plasma by Loren Pickart in 1973 as an activity that restored youthful function to aged liver cells. The biologically active form for nearly every reported effect is the copper(II) complex GHK-Cu, in which the imidazole nitrogen of histidine and the amine groups of glycine and lysine coordinate Cu²⁺. The molecule is best understood as a vector for endogenous copper-handling biology rather than a receptor agonist — the central pharmacology question is what copper does once GHK delivers it into tissue, not what the tripeptide does at a binding site. The GHK triplet itself sits within the alpha-2(I) chain of type I collagen, and the prevailing hypothesis is that wound-site proteases liberate GHK from damaged matrix and locally upregulate repair; Maquart et al. 1988 established the foundational dose-response (peak fibroblast collagen synthesis at 10⁻⁹ M, independent of any change in cell number) and proposed this in-situ liberation model.

The mechanism story has three converging strands. The first is copper-dependent matrix remodeling: Maquart 1988 on collagen synthesis paired with Siméon et al. 2000, which showed GHK-Cu raises MMP-2 mRNA and protein in dermal fibroblasts alongside proportional TIMP-1 and TIMP-2 secretion, with the activity driven by the copper ion rather than the bare tripeptide. The synthesis-plus-controlled-turnover pairing is the hallmark of a coordinated remodeling program rather than one-way deposition, and copper is independently a required cofactor for lysyl oxidase, the enzyme that cross-links collagen and elastin. The second strand is broad transcriptional modulation: Pickart and Margolina 2018 synthesizes gene-expression analyses showing GHK regulates dozens of pathways involved in skin and lung tissue repair, DNA-damage response, neuroprotection, and anti-inflammatory and anti-cancer signaling — a breadth unusual for a tripeptide. The third strand is mitochondrial and stress-response pathway activation: Wen et al. 2026 showed GHK-Cu extends Caenorhabditis elegans lifespan via DAF-16 (FOXO) and SKN-1 (Nrf2-orthologue) activation, restored mitochondrial fusion dynamics by modulating drp-1 / fzo-1 expression, and raised ATP biosynthesis. The cosmetic-pharmacology hair-follicle case is woven through the same biology — copper-dependent dermal-papilla signaling and follicle-cycle modulation rather than a discrete follicle-specific receptor.

02·Overview

GHK-Cu sits at an unusual junction in the corpus: it has both the deepest cosmetic adoption of any peptide on this site and a much richer preclinical literature than its dermatology reputation suggests. The applied case with the most human evidence is dermatological. Topical GHK-Cu has been formulated into cosmetic and prescription skincare globally for three decades, with 12-week placebo-controlled trials in photoaged skin reporting increases in skin density, dermal collagen, and clarity, plus reductions in fine-line depth across replications. The hair-density decision guide and the soft-tissue healing decision guide walk the applied-context detail for the two indications that dominate practitioner conversations.

The mechanism and gene-expression evidence is the second pillar. Pickart and Margolina 2018 is the most current authoritative synthesis of GHK's transcriptional breadth — fibroblast collagen, elastin, and glycosaminoglycan synthesis; copper-dependent angiogenesis; cytoprotective effects across skin, lung, bone, liver, and gastric tissues in animal models; and gene-level modulation of dozens of repair, stress-response, and anti-inflammatory pathways. The honest read on this body of work: the gene-expression signal is real, replicated across cell lines and animal models, and unusual in its breadth — but the translation from gene-level effect to consequential clinical outcome is established primarily for the cosmetic skin endpoints and is much less mature for the non-skin indications the breadth implies. The Wen 2026 C. elegans lifespan and DAF-16 / SKN-1 finding is the first organismal-longevity test of those gene-expression claims in a tractable model and parallels the SS-31 mitochondrial-fusion mechanism, but it is single-laboratory, abstract-only on key quantitative endpoints, and a long way from mammalian healthspan.

The biohacker injectable and systemic-dosing case rests on the mechanism literature plus extrapolation from cosmetic-topical efficacy rather than on direct trial evidence. Controlled human trials of injected or systemic GHK-Cu are absent. The Mendias and Awan 2026 Sports Medicine review groups GHK-Cu with the broader unapproved-gray-market peptide channel in its clinician-facing framework, noting favorable tissue-repair signals in animal models alongside scarce rigorous human safety data and real potential for patient harm via the unregulated sourcing channel. The mechanism is more about endogenous copper-handling biology than receptor agonism, which distinguishes GHK-Cu sharply from the receptor-class peptides on this site — and which is the source of the load-bearing safety consideration: the copper(II) ion is the active center, and excessive copper exposure carries real toxicity (Wilson's disease in chronic excess, gastrointestinal symptoms acutely). Treat the cosmetic-topical evidence as moderately mature, the mechanistic literature as broad but not yet translated to non-skin outcome trials, and the injectable systemic case as preclinically supported and clinically uncharacterized.

03·Methodological caveats
04·Applied translation
05·6 primary sources

Each entry below is graded on the four-tier evidence scale (peer-primary → practitioner) and carries an independent strength label that captures how robustly the source supports the claim it backs on this page.

06·Related dossiers + decision guides

Goal-oriented comparisons and mechanism deep-dives that cover GHK-Cu. Decision guides compare the realistic options for a goal (peptide / drug / lifestyle); mechanism dossiers walk the pathway in depth.

Decision guides all guides →

Mechanism dossiers

07·Documented protocols — registry preview

Editorially synthesized protocols below — derived from published RCTs and practitioner case-series, each citing its source. The full registry view (all editorial patterns, all community-reported cycles, and member-logged cycles with paired biomarker deltas and adverse-event incidence aggregated at k≥5) is published to members.

Editorial protocols
3
Community-reported cycles
1
Member-logged cycles
0

  1. 01·Editorial protocol

    Skin appearance (anti-aging, wound healing context)

    Editorial

    Protocol

    10.0000 mg·BID topical (formulation-dependent concentration)·topical

    Outcome

    3 / 5 synthesized rating

    Provenance: Editorial pattern from the Pickart-group review literature (Biomolecules 2018 review). The protocol is the typical cosmetic-formulation use; outcome rating reflects the modest-but-consistent dermatological-literature signal.

  2. 02·Editorial protocol

    Hair density (AGA adjunct, topical scalp)

    Editorial

    Protocol

    1.0000 mg·QD topical (concentration-dependent — typical 0.5–2% in carrier)·topical

    Outcome

    3 / 5 synthesized rating

    Provenance: Editorial pattern from the Pickart 2018 IJMS gene-expression review combined with the small-cohort hair-density cosmetic-literature signal. Topical-only protocol reflects the community-default verified across ~22 sources in the hair-density decision guide; the pattern is an AGA adjunct to first-line therapy, not a standalone treatment. Outcome rating of 3 reflects modest-but-replicated direction + mechanistic plausibility against the limited large-RCT base specifically for hair. · Source

  3. 03·Editorial protocol

    Topical wound healing and dermal repair

    Editorial

    Protocol

    10.0000 mg·BID topical (formulation-dependent concentration)·topical

    Outcome

    3 / 5 synthesized rating

    Provenance: Editorial pattern from the Maquart 1988 collagen-synthesis primary + the Siméon 2000 MMP-2 / TIMP-paired remodeling primary. Topical protocol reflects the typical cosmetic-formulation use; the mechanism case for coordinated matrix remodeling is mature, while the direct large-RCT outcome evidence for surgical-wound or procedure-site healing at this exact protocol is more limited than the mechanism. Outcome rating of 3 reflects the well-replicated mechanism + decades of topical safety record against the limited large-RCT dermal-wound base specifically. · Source

→·See the full registry

Members see 3 editorial protocols, 1 community-reported cycle, 0 consented member cycles, paired biomarker delta aggregations, and adverse-event incidence by class — all for GHK-Cu.

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08·Safety

Topical GHK-Cu has a long safety record in cosmetic use; reported reactions are mostly mild contact irritation or rare hypersensitivity. Injectable use is less well-characterized in human safety data — the most consistent practitioner-reported events are injection-site reactions (mild redness or warmth) and rare systemic flushing. The copper component is the source of the principal safety concern at higher injectable doses or with prolonged systemic exposure: total copper intake from food, supplements, and any GHK-Cu administration should stay well below the IOM upper-limit threshold for copper (10 mg/day for adults) to avoid copper accumulation. This concern is largely irrelevant for topical cosmetic use at typical concentrations and entirely relevant for high-dose injectable protocols.

Contraindications

  • Wilson's disease or any disorder of copper metabolism (active or genetic)
  • Active hepatic disease (the liver is the primary route for copper handling)
  • Pregnancy or breastfeeding (no controlled human safety data for injectable use)
  • Known copper hypersensitivity
  • Concurrent high-dose copper supplementation (cumulative copper risk)
  • Patients under 18 (no controlled safety data in this population for injectable use)
  • Active infection at the injection site

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Last reviewed: 2026-04-28

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