GHK-Cu: The Copper Peptide Guide

GHK (Gly-His-Lys) is a copper-binding tripeptide found in human plasma, saliva, and urine. It was discovered in 1973 during liver research. Bound to copper (GHK-Cu), it activates wound repair genes, stimulates collagen and elastin production, and modulates over 4,000 genes related to tissue remodeling.

Plasma GHK-Cu concentrations drop from ~200 ng/mL at age 20 to ~80 ng/mL at age 60. The replenishment hypothesis drives both cosmetic and injectable use.

Skin: Multiple RCTs show topical GHK-Cu improves skin density, reduces fine lines, and accelerates wound healing. This is the best-evidence application.

Hair: Small studies and anecdotal reports suggest scalp application or injection may stimulate follicle activity. Mechanism: increased blood vessel formation and reduced follicle inflammation. Weaker evidence than skin.

Systemic (injectable): Animal studies show anti-inflammatory and tissue repair effects. Human injectable data is limited to small anti-aging clinic reports — not peer-reviewed RCTs.

Gene modulation: GHK-Cu resets expression of genes involved in inflammation, oxidative stress, and tissue repair. Impressive in vitro; in vivo human relevance at supplemental doses is uncertain.

Topical (skincare): 1–2% GHK-Cu serum applied to face/scalp nightly. Results visible in 8–12 weeks for skin. The Ordinary, Skin Biology, and prescription Cu3+ products are common.

Injectable: 1–2mg subcutaneous daily or every other day for 4–8 weeks. Reconstitute lyophilized peptide with bacteriostatic water. Rotate injection sites (abdomen, thigh).

Hair protocol: Some inject subQ near scalp or use microneedling + topical GHK-Cu combo. Minoxidil + GHK-Cu is a common stack in r/tressless.

Cycling: 4–8 weeks on, 4 weeks off. Continuous use data doesn't exist.

Topical: Legal OTC cosmetic ingredient in US, UK, EU, AU, and NZ.

Injectable: Not FDA-approved for human injection in the US. Sold as 'research chemical' from peptide suppliers. Legal for personal import varies by country — see peptides intro guide.

Compounding pharmacies: Some US compounding pharmacies offer GHK-Cu with prescription. Anti-aging clinics administer it legally in clinical settings.

Copper overload: Excessive copper supplementation causes liver damage. GHK-Cu delivers small copper amounts, but stack with other copper sources cautiously.

Injection risks: Same as all peptides — sterile technique, quality sourcing, infection risk. See peptide reconstitution kit guide.

Topical irritation: Rare contact dermatitis. Patch test first.

Cancer caution: Theoretical concern that tissue growth factors could affect tumor microenvironment. Avoid with active malignancy without oncologist approval.

r/Peptides and r/SkincareAddiction overlap on GHK-Cu. Skincare community: 'best peptide for anti-aging, proven.' Peptide community: 'injectable is under-researched but promising for systemic repair.'

Hair loss forums rank it below finasteride/minoxidil but above most snake oils. Realistic expectations: modest improvement, not hair transplant results.