Educational reference only. Not medical advice. Consult a healthcare provider before starting any protocol.
GHK
Glycyl-L-Histidyl-L-Lysine
What it is
A naturally occurring tripeptide (Gly-His-Lys) first isolated from human plasma in 1973 by Dr. Loren Pickart. GHK is present in plasma at ~200 ng/mL in youth, declining to ~80 ng/mL by age 60. It is released from collagen and the glycoprotein SPARC during tissue injury, functioning as a matrikine signal peptide that coordinates wound repair. GHK has extremely high affinity for copper(II) ions and naturally forms the GHK-Cu complex in vivo; this entry covers the base tripeptide without copper. GHK independently possesses antioxidant activity, quenching hydroxyl and peroxyl radicals and neutralizing toxic lipid peroxidation aldehydes like 4-hydroxynonenal. Connectivity Map analysis showed GHK modulates expression of approximately 31% of human genes, with broad effects on DNA repair, anti-inflammatory, and tissue remodeling pathways. Note: for the copper-complexed form, see ghk-cu.
Community-reported ranges
Research data sourced from published preclinical and in vitro literature. Topical concentrations from cosmetic industry standards. GHK is not approved as a drug in any jurisdiction. Not dosing guidance.
Reported dose range
0–0 mcg
Estimated half-life
~30-60 minutes (plasma, IV administration)
Source: Preclinical pharmacokinetic data
Reported cycle length
4–12 weeks on
Not established; continuous topical use is common weeks off
Route
topical
Common vial sizes
topical serums (0.01-1%)
Reported timing
AM & PM topical application
Reported frequency
Topical: 1-2x daily application. Not typically used in injectable form without copper complexing.
Frequently discussed alongside
Based on community forum discussions. Not a recommendation to combine compounds.
GHK-Cu
GHK is the base tripeptide; GHK-Cu is the copper-complexed bioactive form with overlapping but enhanced properties
BPC-157
Both discussed in tissue repair and wound healing contexts
Palmitoyl Pentapeptide-4 (Matrixyl)
Both are signal peptides used topically for collagen stimulation and anti-aging
Epithalon
Both discussed in anti-aging and gene expression modulation contexts
Published research
GHK was first characterized as a liver cell growth factor from human plasma (Pickart, 1973). Subsequent research demonstrated effects on collagen I/III synthesis, elastin production, glycosaminoglycan production, metalloproteinase regulation, and growth factor release (VEGF, BDNF, BMP-2, FGF) at picomolar-to-nanomolar concentrations. Broad Institute Connectivity Map analysis revealed GHK modulates ~31.2% of all human genes (at ≥50% change), including upregulation of 47 DNA repair genes. A multi-institutional study demonstrated GHK could reverse gene expression signatures associated with COPD/emphysema. The peptide also possesses independent antioxidant activity, quenching hydroxyl and peroxyl radicals. Most research has been conducted on the copper-complexed form (GHK-Cu); the base tripeptide's independent biological activity is less extensively characterized in isolation. No human clinical trials exist for GHK as a standalone therapeutic agent.
Reported side effects
From community self-reports. Not from controlled studies.
GHK has an excellent safety profile across decades of topical cosmetic use. Rare reports of mild transient redness or itching with topical application. Anecdotal reports of temporary worsening of skin appearance with overuse, theoretically from excessive metalloproteinase activity. At very high systemic doses (~300x therapeutic concentrations), blood pressure lowering has been observed in animal models. No significant adverse effects documented in published literature for topical use.
Regulatory status
FDA (United States)
Not approved as a drug. The copper-complexed form (Copper Tripeptide-1 / GHK-Cu) is a recognized cosmetic ingredient and was added to the FDA 503A Category 1 compounding list in October 2023.
Health Canada
Not authorized as a therapeutic product. Recognized as a cosmetic ingredient in topical formulations.
WADA (Competitive Athletes)
Not explicitly listed on the WADA Prohibited List. Topical use is generally considered permissible. Injectable use may fall under catch-all provisions in S2.3 (growth factors and modulators), creating regulatory ambiguity for competitive athletes.
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