Carl read the papersWhat it actually is
GHK is a three-amino-acid peptide that binds copper (GHK-Cu). It occurs naturally in plasma and declines with age, which sparked interest in supplementing it.
It’s among the best-studied cosmetic peptides, with real data on collagen synthesis, wound healing and skin remodeling — plus hair and anti-inflammatory research.
How it’s thought to work
- Collagen synthesis — stimulates collagen, elastin and glycosaminoglycans.
- Wound remodeling — supports tissue repair and reduces scarring.
- Antioxidant/anti-inflammatory — modulates inflammation and oxidative stress.
- Gene signalling — reported to shift expression toward a ‘younger’ profile.
What the research says
Strong cosmetic and wound-healing literature, largely topical. Injectable/systemic anti-aging claims are far less established.
- Skin firmness, collagen and wrinkle research.
- Wound healing and scar reduction.
- Hair-follicle and anti-inflammatory studies.
Watch: GHK-Cu explained
Video by The Zero Downside on YouTube. Not affiliated with Peptide Carl and not an endorsement — included because a second explanation of the same mechanism is often what makes it click.
Reported protocols
These are the doses the peptide community actually reports running (Reddit & forums), alongside published research — logged for education, not as a recommendation to use.
| Parameter | Commonly reported range |
|---|---|
| Community dose | 1–2 mg/day subQ (systemic); 0.5–1% serum (topical) |
| Frequency | Once daily (injectable often pre-bed) |
| Route | SubQ for systemic/hair; topical serum for skin |
| Cycle | 4–8 wk blocks; some run topical 12+ months |
| Community tip | More isn’t better — 3–5 mg matched 1–2 mg; purity dominates results |
Common use cases
| Goal | Community protocol notes |
|---|---|
| Skin / collagen | 1–2% topical serum daily, or 1–2 mg subQ |
| Hair | subQ, 5 days/wk |
| Wound / scar repair | topical or subQ, 4–8 wk blocks |
Mixing it (reconstitution)
Freeze-dried peptides must be reconstituted with bacteriostatic water before they can be measured. Carl’s calculator turns “mg in the vial + ml of water + target dose” into “units on the syringe” — and tells you how long the vial lasts.
→ Open the Reconstitution Calculator
Injection & handling
SubQ 1–2 mg/day (often pre-bed) for systemic/hair, or a 1–2% topical serum for skin. Rotate injection sites. Copper content means product quality dominates results. Refrigerate reconstituted.
Stacks it appears in
- Skin & Repair — GHK-Cu + BPC-157 — remodeling plus general repair (reported).
Sources
- GHK found in human serum, Nat New Biol 1973 (PMID 4349963)
- GHK-Cu review incl. age decline and gene data, Int J Mol Sci 2018 (PMID 29986520)
- GHK-Cu stimulates collagen synthesis in fibroblasts, FEBS Lett 1988 (PMID 3169264)
- GHK-Cu and glycosaminoglycans in wounds, J Invest Dermatol 2000 (PMID 11121126)
- GHK reverses an emphysema gene signature, Genome Med 2012 (PMID 22937864)
- Topical GHK-Cu gel in diabetic ulcers, RCT, Wound Repair Regen 1994 (PMID 17147644)
- GHK-Cu after CO2 laser resurfacing, RCT, Arch Facial Plast Surg 2006 (PMID 16847171)
- Topical peptides for aged skin, review, Int J Cosmet Sci 2009 (PMID 19570099)
- GHK-Cu and growth factors in fibroblasts, Arch Facial Plast Surg 2005 (PMID 15655171)
- FDA: bulk substances that may present significant safety risks (Apr 2026)
