Direct Answer
GHK is the tripeptide Gly-His-Lys (copper-free form) studied in skin and wound-healing research; most functional data concern the copper complex GHK-Cu.
Summary Table
Evidence Level
Preclinical
AI Summary
GHK is a naturally occurring tripeptide (Gly-His-Lys) found in human plasma; this entry covers the copper-free form (the copper complex, GHK-Cu, is covered separately). The evidence base is preclinical: review and laboratory literature describe proposed roles in skin remodeling, wound healing, and gene expression, but much of the functional data concerns the copper-bound complex rather than the copper-free peptide, and independent controlled human outcome trials of the copper-free form are limited. Framed as studied, not established for defined clinical outcomes.
Key Information
Classification
Key Takeaways
- GHK is the endogenous tripeptide Gly-His-Lys (copper-free form); the copper complex GHK-Cu is covered separately
- Most functional evidence concerns GHK-Cu rather than the copper-free peptide
- It is used as a cosmetic ingredient, not an approved medicine, and human outcome data are limited
Scientific Overview
In Plain English
GHK is a small natural peptide (three amino acids) found in the blood that declines with age. Research, mostly in the lab, has looked at its role in skin and wound repair. Most of the functional studies actually use the copper-bound version (GHK-Cu). It is used as a cosmetic ingredient rather than an approved medicine.
Scientific Details
GHK (Gly-His-Lys) is an endogenous tripeptide present in human plasma that decreases with age. Review and laboratory literature describe proposed roles in tissue remodeling, wound healing, antioxidant activity, and modulation of gene expression. Much of this literature concerns the copper complex GHK-Cu, which binds copper with high affinity; evidence specific to the copper-free peptide, and independent controlled human outcome data, are limited.
How It Works
GHK is described in research as a copper-binding tripeptide associated with tissue-remodeling and gene-expression effects in laboratory models. The copper complex (GHK-Cu) is the form most studied for these activities. These mechanisms are characterized preclinically and are not confirmed by controlled human outcome studies for the copper-free peptide.
Mechanism of Action
Copper binding
cell
GHK binds copper(II) to form GHK-Cu; much of the peptide's described biological activity is attributed to the copper complex.
Gene-expression modulation
cell
Review and laboratory literature associate GHK/GHK-Cu with changes in expression of genes related to tissue remodeling and repair.
Evidence Level
Human Evidence
Human evidence largely concerns the copper complex (GHK-Cu) in topical/cosmetic contexts; independent controlled human outcome data specific to the copper-free peptide are limited.
Animal Evidence
Animal wound-healing studies describe tissue-remodeling effects, generally with the copper complex.
Cell Evidence
In vitro studies describe gene-expression and remodeling effects.
Limitations
Most functional evidence concerns GHK-Cu rather than the copper-free peptide; controlled human outcome trials are limited, and effects are not established for defined clinical endpoints.
Why This Grade
Graded preclinical: evidence is largely review- and laboratory-based, concerns the copper complex more than the copper-free peptide, and lacks independent controlled human outcome data.
Frequently Asked Questions
What's the difference between GHK and GHK-Cu (copper peptide)?
GHK is the copper-free tripeptide glycyl-L-histidyl-L-lysine (INCI Tripeptide-1). GHK-Cu (INCI Copper Tripeptide-1) is the same peptide bound to copper. GHK binds copper to form GHK-Cu, and much of the peptide’s described biological activity is attributed to the copper complex. Most of the functional research — including wound-healing and gene-expression effects — concerns GHK-Cu rather than the copper-free peptide, and independent controlled human data specific to copper-free GHK are limited. This distinguishes the two forms; it is not a claim that either form is proven more effective in skincare.
How is GHK thought to work?
GHK binds copper(II) to form GHK-Cu, and much of its described biological activity is attributed to the copper complex. Review and laboratory literature associate GHK/GHK-Cu with changes in the expression of genes related to tissue remodeling and repair. These are cell- and animal-level findings rather than established human outcomes.
Is copper-free GHK proven to work in skincare?
Evidence specific to the copper-free peptide is limited. Most functional data concern the copper complex GHK-Cu; human evidence largely concerns GHK-Cu in topical/cosmetic contexts, and independent controlled human outcome data specific to copper-free GHK are limited, with effects not established for defined clinical endpoints. It is graded preclinical.
Can GHK be injected or used systemically?
Injectable or systemic use is not supported by controlled human safety data. GHK is used as a cosmetic (topical) ingredient and is not an approved medicine; evidence specific to the copper-free peptide is limited.
References
- The potential of GHK as an anti-aging peptide. Aging Pathobiology and Therapeutics.Reviewdoi:10.31491/apt.2020.03.014 →
- Topically applied GHK as an anti-wrinkle peptide: Advantages, problems and prospective. BioImpacts.Reviewdoi:10.34172/bi.30071 →
Alternative Names
- Glycyl-L-histidyl-L-lysine
- Gly-His-Lys
- Tripeptide-1
- GHK (copper-free)
Risks & Safety
- Not an approved medicine; used as a cosmetic ingredient with the usual patch-test considerations
- Evidence specific to the copper-free peptide is limited; most data concern GHK-Cu
- Injectable or systemic use is not supported by controlled human safety data
Claim Boundaries
ION BLUE is an educational research aggregator. This content summarizes published scientific literature. It is not medically reviewed, is not medical advice, and is not a recommendation to use any substance. Consult a licensed healthcare provider. This entry summarizes research on the GHK tripeptide and is not a recommendation to use it for any clinical purpose. See copper-tripeptide-1 for the copper complex.
This page summarizes published research and is for informational purposes only; it is not medical advice.