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Copper tripeptide

GHK-Cu

Also known as: Copper Tripeptide-1, Glycyl-L-histidyl-L-lysine copper

Tier 2 — Human observationalReviewed 2026-04-30

Strong topical evidence in skin and wound healing. Injectable systemic claims are an entirely different evidence base and tier.

Ask about GHK-Cu

Answers are grounded in the literature ingested for this peptide. Every clinical claim cites a source. Out-of-scope questions (pediatric dosing, pregnancy, oncology, personal medical advice) will be refused. Beta — verify everything important with your clinician.

Examples: “What dose was used in the SURMOUNT-1 trial?” · “Are there any cardiovascular outcome data?”

Overview

GHK-Cu is a naturally occurring tripeptide (glycyl-L-histidyl-L-lysine) that binds copper(II) with high affinity. Endogenous plasma levels decline with age. Topical formulations have been studied in cosmetic dermatology and wound healing for decades, with multiple human clinical trials supporting efficacy in skin elasticity, wound closure, and dermal repair markers. Injectable systemic GHK-Cu is a separate proposition: there are essentially no published human RCTs for systemic outcomes, and pharmacokinetics of injected GHK-Cu in humans are not well characterized.

Mechanism

Copper-binding tripeptide that modulates inflammation, gene expression involved in extracellular matrix remodeling, and antioxidant defenses in dermal cells. Pickart and colleagues have characterized broad transcriptomic effects in vitro. Whether these in-vitro effects translate to systemic outcomes via injection is undemonstrated.

Evidence by indication

We classify each indication separately. The same peptide can be Tier 1 for one use and Tier 4 for another. Tiers reflect the published literature, not the strength of community framing.

Topical skin aging / wound healing

Tier 2high confidence

Multiple human studies of topical GHK-Cu formulations show measurable improvements in skin elasticity, wound closure rate, and dermal markers. Studies are generally small (n<50) and often industry-funded, preventing Tier 1.

Pickart L et al. 2018Finkley MB et al. 2005

Hair growth (topical)

Tier 3medium confidence

Some small topical hair-growth studies exist, mostly from dermatology or cosmetic research with weak controls. Independent replication is limited.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Injectable systemic effects (longevity, mitochondrial, hair, immune)

Tier 3high confidence

No published human RCTs of injectable GHK-Cu for systemic outcomes. Animal studies suggest tissue-protective effects. Bioavailability and pharmacokinetics of injected GHK-Cu in humans are not well characterized.

Pickart L et al. 2018

Studied dose ranges

The ranges below come from published trial protocols where available, and from documented self-experimenter consensus where the literature does not include human dose-finding work. The notes flag which is which.

1,000–5,000 mcg1× daily · subcutaneous (research only)

Reported self-experimenter ranges are 1–5 mg subcutaneous, often pulsed over a few weeks. These dose ranges are not from human RCTs and should not be presented as 'studied' for systemic outcomes.

Contraindications

  • Wilson's disease and other copper metabolism disorders
  • Known sensitivity to copper
  • Pregnancy and breastfeeding (limited safety data for systemic use)
  • Active malignancy (theoretical: GHK-Cu modulates angiogenesis pathways)

Reported side effects

  • Topical: mild irritation, transient erythema
  • Injectable: injection site reactions, headache, possible metallic taste reported anecdotally
  • Theoretical risk of copper accumulation with chronic high-dose systemic use

Reconstitution & storage

Lyophilized powder reconstituted with bacteriostatic water. Note: GHK-Cu is light- and air-sensitive — handle quickly and store away from light. Topical formulations should be obtained from cosmetic-grade suppliers, not reconstituted from injectable lyophilizate.

Storage. Lyophilized: refrigerate 2–8 °C, protect from light. Reconstituted: refrigerate, use within 30 days, protect from light.

Open the peptide calculator → to compute exact draw volumes for your specific vial and BAC water choice.

Editorial note

GHK-Cu is the canonical example of why we tier per indication, not per peptide. Topical = Tier 2 with real human studies. Injectable for systemic outcomes = Tier 3. Transferring evidence across delivery routes is the most common error here.

Citations

  1. [1]
    The Human Tripeptide GHK-Cu in Prevention of Oxidative Stress and Degenerative Conditions of Aging: Relevance to Cosmetic Dermatology and the Cellular Mechanisms
    Pickart L, Margolina A · Biomolecules · 2018 · PMID 29455509
    Comprehensive mechanism and dermatology review used as a Tier 2 anchor.
    View source
  2. [2]
    Copper peptide and skin
    Finkley MB, Appa Y, Bhandarkar S · Cosmeceuticals (book chapter) · 2005 · PMID 16030655
    Topical clinical evidence reference for Tier 2 dermatologic claims.
    View source