Encyclopedia · protein or peptide
GHK-Cu (copper tripeptide-1)
GHK-Cu is a copper-binding peptide with a long skin-repair record but no published controlled trial for hair growth.
What it is
GHK is a three-amino-acid peptide (glycine-histidine-lysine) that binds copper. It is sold in cosmetic serums, scalp boosters and, increasingly, as a "research peptide" for injection. Reviews describe it as a skin-remodeling signal (Pickart 2008; Pickart 2015). It should not be confused with AHK-Cu, the analogue that has the hair follicle lab data; see AHK-Cu.
How it works
The proposed picture is that it delivers copper to cells, nudges collagen turnover, and modulates growth-factor and inflammatory signals (Pickart 2015, a review by the peptide's discoverer, so treat enthusiasm with care). For hair, the idea is more blood-vessel support and a healthier dermal papilla. Those links come from the AHK-Cu study, not from GHK-Cu itself.
What the studies show
- AHK-Cu, a related peptide and not GHK-Cu, lengthened human hair follicles and boosted papilla-cell growth in the lab at very low concentrations. Pyo 2007
- Two reviews cover GHK as a skin and tissue remodeling signal, with hair as a minor theme and mostly cell and animal data. Pickart 2008; Pickart 2015
- A copper tripeptide serum used with a hydroxy-acid scrub in scalp seborrheic dermatitis was reported, but that study does not test hair growth. Patel 2024
- A search for GHK-Cu with hair found only reviews, a zebrafish study and a formulation paper, and no human hair-growth trial.
How it's used in studies
No hair-growth dosing exists in controlled human data. The AHK-Cu lab work used 10^-12 to 10^-9 mol/L, which says nothing about a serum percentage. Commercial hair serums vary widely and rarely disclose concentration.
Side effects and safety
Topical use is generally described as well tolerated, but no scalp-use safety study was found. Copper peptides are often layered with microneedling, which raises absorption and irritation risk. Injectable "research peptide" GHK-Cu is not an approved drug. Check regional rules before buying; in the EU and UK it is treated as a cosmetic ingredient only if no medicinal claim is made.
Bottom line
For hair growth the evidence is mechanism and lab data only. It is a reasonable low-risk optional scalp-care add-on if you like it, but it should not replace minoxidil or other proven treatments, and injectable products are best skipped. Discuss with a doctor.
Fun facts
GHK was first isolated from human plasma, and its levels are reported to decline with age. The claim comes from the peptide's discoverer (Pickart 2008) and has not been independently established.
Studies 4
Pyo HK et al. The effect of tripeptide-copper complex on human hair growth in vitro. Arch Pharm Res. 2007
Tested: AHK-Cu at 10^-12 to 10^-9 mol/L
Result: Follicles grew longer and dermal papilla cells proliferated more; the fall in cell death at the highest dose was not statistically significant.
Read the study ↗Pickart L. The human tri-peptide GHK and tissue remodeling. J Biomater Sci Polym Ed. 2008
Tested: GHK and GHK-Cu
Result: Describes GHK as a skin and tissue remodeling signal; hair is a minor theme.
Read the study ↗Pickart L et al. GHK peptide as a natural modulator of multiple cellular pathways in skin regeneration. Biomed Res Int. 2015
Tested: GHK peptide
Result: Describes multi-pathway skin regeneration effects, mostly from cell and animal data.
Read the study ↗Patel MN et al. Hydroxy acid scrub plus copper tripeptide serum in seborrheic dermatitis. Cureus. 2024
Tested: hydroxy acid scrub plus copper tripeptide serum
Result: Reported on a scalp regimen for seborrheic dermatitis; it does not test hair growth.
Read the study ↗Related
- AHK-Cu (copper tripeptide-3)AHK-Cu is a copper peptide that lengthened human hair follicles in a 2007 lab study but has no human hair-growth trial.
- Biotinoyl tripeptide-1Biotinoyl tripeptide-1 is biotin attached to the GHK peptide; the only hair-growth data are manufacturer claims.
- Microneedling for hair lossRolling or stamping fine needles into the scalp is a cheap add-on to minoxidil that helped in small trials, but it has not worked on its own and the largest trial found no extra benefit.
- MinoxidilThe most widely used hair-growth treatment, available as a cheap over-the-counter lotion or foam and as a prescription tablet, with a mechanism that is still only partly understood.