What is GHK-Cu?
Copper peptide for skin, hair, and healing. The most studied cosmetic peptide.
GHK-Cu (glycyl-l-histidyl-l-lysine copper) is a naturally occurring tripeptide that declines with age. It is the most researched cosmetic peptide with over 60 studies. Topically, it stimulates collagen synthesis, improves skin elasticity, reduces fine lines, and accelerates wound healing. For hair, it can extend the growth phase and improve thickness. The copper component is essential for many enzymatic processes in tissue repair. Beyond topical use, some use injectable GHK-Cu for systemic anti-aging effects, though human data for injection is limited. In studies, it resets gene expression patterns toward a younger state and reduces inflammation. Users of topical products report firmer skin, faster healing of cuts/acne, and improved skin texture over 2-3 months. Injectable users report general skin quality improvement and some claim enhanced healing. The injectable form is more experimental but increasingly popular in the longevity community. Generally well-tolerated with minimal side effects.
What the evidence says
The overall evidence grade for GHK-Cu is B (moderate — mixed or smaller trials, reasonable mechanistic support). Strong evidence for topical skin benefits. Gene expression studies impressive. Injectable use less proven.
Specific findings with supporting evidence:
- Stimulates collagen and elastin synthesis. Evidence grade A.
- Accelerates wound healing. Evidence grade A.
- Resets gene expression toward youthful patterns. Evidence grade B.
- Supports hair growth and thickness. Evidence grade B.
- Anti-inflammatory effects. Evidence grade B.
Best-supported outcomes:
- Skin firmness and elasticity.
- Wound healing.
- Fine line reduction.
- Hair support.
Where marketing outpaces evidence:
- Marketing often overstates: Reverses aging dramatically.
- Marketing often overstates: Injectable is proven.
Dose and timing
Take it in the evening. Topical: apply to clean skin nightly. Injectable: typically subcutaneous.
Who it's for, and who should skip it
Most relevant for:
- Those seeking skin quality improvement.
- Anti-aging focus.
- Wound/scar healing.
- Hair thinning.
Not appropriate for:
- Those with copper sensitivity.
- Wilson disease.
Safety and cautions
Copper overload. Very high doses could theoretically cause copper toxicity. Stick to normal protocols. Caution: Injectable less proven. Topical is well-established. Injectable is more experimental. Patience required. Skin changes take 8-12 weeks to become noticeable.
Common mistakes
- Expecting overnight results.
- Using with conflicting actives (certain acids can degrade it).
- Not being consistent.
Myths vs reality
A common misconception: All copper peptides are the same. In reality, gHK-Cu specifically has the research. Other copper peptide forms may not have same effects. A common misconception: Injectable GHK-Cu is dangerous. In reality, no significant safety concerns have emerged, but long-term human injection data is limited.
How it interacts with other compounds
- GHK-Cu works well alongside bpc 157 — both support tissue regeneration - systemic healing stack.
- GHK-Cu works well alongside tb 500 — complementary healing mechanisms.
Questions people ask
Topical vs injectable? Topical is proven for skin. Injectable is for those wanting potential systemic effects but is more experimental.
Can I use it with retinol/acids? Some actives can degrade GHK-Cu. Use at different times of day or on alternating days.
How long to see results? Topical skin improvements typically noticeable in 8-12 weeks of consistent use.
Editorial note
This guide summarizes the published evidence on GHK-Cu. It is educational content, not medical advice. Confirm with your clinician if you take prescription medications or manage a chronic condition.