GHK-Cu
A naturally occurring copper-binding tripeptide (glycyl-L-histidyl-L-lysine complexed with copper) used topically and by injection for skin regeneration, wound healing and hair growth. It has genuine in-vitro and some small topical clinical support for cosmetic skin benefits, but injectable 'anti-aging' use rests on preclinical work and anecdote.
01 Overview
GHK-Cu is a copper complex of the tripeptide GHK, which occurs naturally in human plasma and declines with age. In cell culture it modulates genes involved in tissue remodelling, stimulates collagen and glycosaminoglycan synthesis, and shows antioxidant and wound-healing activity. Topical GHK-Cu is a long-standing cosmetic ingredient with some small human studies suggesting improved skin firmness, wrinkles and hydration.
The distinction that matters: topical/cosmetic skin benefits have modest human support, whereas the systemic injectable use promoted in peptide circles (for whole-body 'anti-aging', deep wound healing or hair restoration) is largely extrapolated from in-vitro and animal data. Injecting a copper-containing peptide also raises the theoretical issue of copper load, which is not well studied in this context.
02 Mechanism
The GHK tripeptide binds copper(II) and acts as a signalling molecule, upregulating collagen, elastin and glycosaminoglycan production, modulating matrix metalloproteinases, and influencing a broad set of tissue-remodelling and antioxidant genes.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Topical cosmetic | 1–3 mg/day | Transdermal | Typical topical serum/cream concentration around 0.05-2%. Best-supported route. |
| Injectable anecdotal | 1–2 mg/day | SubQ | Used by some for systemic effect or localised healing; not clinically validated and adds a copper load. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Improved skin firmness and wrinkles (topical)Small topical studies report improved elasticity, wrinkle depth and hydration. | Clinical | ||
| Stimulated collagen and wound healingIncreases collagen and glycosaminoglycan synthesis and accelerates wound closure in vitro and in animals. | Preclinical | ||
| Hair growth supportPromoted for hair follicle stimulation; limited controlled evidence. | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Skin irritation (topical)Redness, stinging or contact irritation, more likely at higher concentrations or combined with acids. | Mild | Common at higher concentrations | Observational | |
| Copper accumulation (injectable, theoretical)Repeated injection delivers copper systemically; cumulative copper effects with this route are unstudied. | Moderate | Unquantified | Unconfirmed |