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What it does - plain English
GHK-Cu is a tripeptide (a peptide made of three amino acids - the smallest possible peptide chain) bound to a copper atom. Your body makes it naturally; levels drop sharply as you age. In skin, it stimulates collagen and elastin production (the proteins that keep skin firm and elastic), accelerates wound healing, and reduces oxidative damage. The skincare industry has used GHK-Cu in serums for decades.
The biohacker community uses it as an injectable for hair regrowth and connective-tissue repair. The human evidence for injectable use is much thinner than the topical evidence. Those are two different use cases with two different evidence bases, and it matters which one you're evaluating.
Status
A-tier topical. B-tier injectable. The topical literature is solid: peer-reviewed papers show measurable improvements in skin firmness, fine lines, and wound healing. The injectable literature is mostly extrapolation from animal models and Pickart's lab work from the 1990s onward.
If you're choosing one form, topical is the safer evidence-based bet. If you're injecting, you're in research-peptide territory. Go in with eyes open about what the evidence actually says.
Legal status
Topical formulations are widely available over the counter. Skincare brands sell them. No prescription needed.
Injectable GHK-Cu is not FDA-approved for human use. It sits in the same research-peptide gray zone as BPC-157. Compounding pharmacies dispense injectable forms with a prescription in some states. Outside of that path, you're in research-vendor territory with the same caveats that apply to any unregulated peptide.
Where to source
For topical: well-established skincare brands are your starting point. NIOD's Copper Amino Isolate Serum, The Ordinary's Buffet + Copper Peptides, and custom-blend pharmacies all carry it. These are OTC products with quality controls you can trust.
For injectable: a compounding pharmacy with a prescription is the legal route, or research peptide vendors with a COA (Certificate of Analysis - the lab report verifying purity and concentration). The hair-regrowth subreddit thread that recommends a specific gym-bro vendor without a COA is not a sourcing strategy. Skip that path.
Two studies worth reading
The foundational topical paper
Pickart & Margolina, International Journal of Molecular Sciences
A review covering decades of GHK-Cu research including the 2010 gene-expression analysis showing it modulates over 4,000 human genes. The paper that explains why a tripeptide can do so many seemingly unrelated things.
Skin-firming clinical evidence
Finkey et al., Cosmeceuticals and Active Cosmetics
Clinical evidence for GHK-Cu's effects on aging skin: increased collagen production, improved skin density, reduced fine lines after 12 weeks of topical use. The reason high-end serums with copper peptides cost what they cost.
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Last reviewed · 2026·05·04 · Status reviewed weekly