Copper tripeptide · research peptide (injectable) · cosmetic (topical)

GHK-Cu

Studied for: collagen synthesis, fibroblast migration, skin and hair regeneration, wound healing

GHK-Cu is the tripeptide glycyl-L-histidyl-L-lysine (Gly-His-Lys) bound to copper (Cu²⁺). Identified as an endogenous human plasma tripeptide whose levels decline with age, it has been studied since the 1970s for effects on dermal remodeling. Topical cosmetic use is widespread; injectable use is a separate regulatory category.

Class
Copper tripeptide complex
Sequence
Gly-His-Lys (with Cu²⁺)
Endogenous
Yes — declines with age[1]
Plasma half-life
< 30 minutes (tripeptide class)[2]
Tissue persistence
~12 hours post-administration[2]
Typical reconstitution solvent
Bacteriostatic water (0.9% benzyl alcohol)
Reconstituted storage
2–8 °C refrigerated · protect from light
FDA status
Topical: cosmetic · Injectable: not approved · April 15 2026 503A Cat. 2 removal[3]
Educational reference only. This page summarizes published research and regulatory status. It does not recommend a dose, a route of administration, or an acquisition channel. Topical cosmetic GHK-Cu is regulated under cosmetic rules; injectable GHK-Cu is research peptide material.

Last reviewed April 24, 2026 by the Enhanced Health Editorial Team. See the editorial policy.

What GHK-Cu is

GHK is a tripeptide — three amino acids in a specific order: glycine (G), histidine (H), and lysine (K). The copper form, GHK-Cu, pairs the tripeptide with a copper(II) ion, which binds preferentially at the histidine imidazole ring. The complex is naturally present in human plasma, saliva, and urine. Published studies have reported that GHK plasma levels decline with age — roughly from ~200 ng/mL in young adults to lower values in older cohorts — leading to long-standing interest in GHK-Cu as a regenerative signaling molecule.[1]

Mechanism

  • Collagen and glycosaminoglycan synthesis. GHK-Cu stimulates synthesis of collagen and GAGs in dermal fibroblasts, supporting extracellular matrix rebuilding.[1]
  • Metalloproteinase modulation. GHK-Cu modulates both matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), shifting the balance of extracellular matrix turnover toward remodeling rather than degradation.[1]
  • Fibroblast migration and angiogenesis. Tripeptides of this class stimulate fibroblast migration, enhance collagen deposition at wound sites, and support angiogenesis.[4]
  • Broad transcriptional effects. A 2010 microarray study reported that GHK alters expression of approximately 31.2% of human genes by 50% or more — a striking breadth of effect that frames GHK-Cu as a pleiotropic signaling molecule, not a single-pathway compound.[1]
  • Copper as enzyme cofactor. Copper is required for several enzymes central to wound healing and antioxidant defense, including lysyl oxidase (collagen cross-linking) and superoxide dismutase.

Pharmacokinetics and stability

  • Plasma half-life. Short — less than approximately 30 minutes for tripeptides of this class.[2]
  • Tissue retention. Copper redistributes to tissue stores after peptide degradation. Measurable tissue presence has been reported up to ~12 hours post-administration.[2]
  • Stability challenges. Copper-peptide complexes are particularly sensitive to light, oxidation, and repeated freeze–thaw. Solutions can discolor over time; discard if color or clarity changes.[2]

Regulatory status

  • Topical cosmetic use. GHK-Cu is widely used in cosmetic serums, creams, and over-the-counter topicals. Cosmetic use is regulated under cosmetic rules, not drug rules.
  • Injectable research use. Injectable GHK-Cu is a research peptide and is not FDA-approved for any clinical indication.
  • April 15, 2026 503A update. In the FDA's April 15, 2026 503A categories update, injectable GHK-Cu was listed for removal from Category 2 as one of twelve peptide bulk drug substances affected. Removal from Category 2 is not the same as permission to compound — the Pharmacy Compounding Advisory Committee (PCAC) must review inclusion on the 503A bulks list, and the FDA must subsequently add it.[3]

Storage and handling

  • Lyophilized powder. Store sealed per supplier instructions — typically refrigerated at 2–8 °C or frozen at −20 °C, protected from light.
  • After reconstitution. Refrigerate at 2–8 °C. Protect from light (amber vial or opaque wrap). Avoid vigorous shaking and freeze–thaw. Bacteriostatic water (0.9% benzyl alcohol) is used when multi-draw is planned; sterile water for single-draw.
  • Discard criteria. Color change (solution should be clear blue-green), cloudiness, visible particulates, or any change from baseline appearance.

Reconstitution math

Math only — no dose recommendation. The concentration after reconstitution determines how many insulin-syringe units equal a given mcg or mg amount.

Example 1 · 50 mg vial + 2 mL bac water concentration = 50 mg / 2 mL = 25 mg/mL = 25,000 mcg/mL
1 unit = 0.01 mL = 250 mcg = 0.25 mg
→ 1 mg = 4 units
→ 2 mg = 8 units
→ 5 mg = 20 units
→ 25 mg = 100 units (full syringe)
Example 2 · 50 mg vial + 5 mL bac water concentration = 50 mg / 5 mL = 10 mg/mL = 10,000 mcg/mL
1 unit = 0.01 mL = 100 mcg = 0.1 mg
→ 1 mg = 10 units
→ 2 mg = 20 units
→ 5 mg = 50 units
→ 10 mg = 100 units (full syringe)
Example 3 · 100 mg vial + 2 mL bac water concentration = 100 mg / 2 mL = 50 mg/mL = 50,000 mcg/mL
1 unit = 0.01 mL = 500 mcg = 0.5 mg
→ 1 mg = 2 units
→ 5 mg = 10 units
→ 50 mg = 100 units (full syringe)

Frequently asked questions

What is GHK-Cu?

Tripeptide Gly-His-Lys bound to copper(II). Endogenous in human plasma; levels decline with age. Studied since the 1970s.[1]

What does it do?

Stimulates collagen and GAG synthesis, modulates MMPs/TIMPs, supports fibroblast migration, influences ~31% of human genes ≥50% in culture.[1][4]

What's the half-life?

< 30 min plasma half-life; tissue presence detectable up to ~12 hours post-administration.[2]

How do I reconstitute a 50 mg vial?

Typical: 50 mg + 2 mL bacteriostatic water = 25 mg/mL → 1 unit = 0.25 mg; 2 mg = 8 units. Protect from light; copper complexes are reactive.

Is it FDA-approved?

Topical cosmetic: regulated as cosmetic, widely used. Injectable: not FDA-approved. In the FDA's April 15, 2026 503A categories update, injectable GHK-Cu was removed from Category 2.[3]

Why is it more sensitive to handling?

Copper is reactive. Complex is light- and oxidation-sensitive. Store refrigerated, protect from light, avoid freeze–thaw. Discard if color or clarity changes.

Primary references

  1. Pickart L, Vasquez-Soltero JM, Margolina A. GHK peptide as a natural modulator of multiple cellular pathways in skin regeneration. BioMed Res Int, 2015 (PMC4508379). PMC4508379 · PubMed 26236730
  2. 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 (PMC6073405). PMC6073405
  3. U.S. Food and Drug Administration. 503A Categories Update for April 2026 — notice that GHK-Cu (injectable) was removed from Category 2 as one of twelve peptide bulk drug substances affected by that update. fda.gov/media/94155
  4. Exploring the Role of Tripeptides in Wound Healing and Skin Regeneration: A Comprehensive Review. Int J Med Sci, 2025. medsci.org v22p4175
  5. Gruchlik A, et al. Skin regenerative and anti-cancer actions of copper peptides. Cosmetics 2018, 5(2):29. MDPI Cosmetics 2018

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