AHK-Cu, a lab-made cosmetic ingredient pairing copper with a short protein fragment, is marketed mainly for thicker scalp hair and firmer skin, and increasingly injected. Direct support is one laboratory study on human hair follicles plus company animal experiments; skin claims borrow from a better-studied cousin. Risks of topical use appear mild, but injected products may be impure or contaminated, and long-term or injected safety has not been established. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Serum copper | 80–120 µg/dL | Detects copper excess or deficiency |
| Ceruloplasmin | 25–35 mg/dL | Screens for Wilson disease; reflects copper status |
| Plasma zinc | 90–110 µg/dL | Zinc and copper compete |
| Copper-to-zinc ratio | Near 1.0 | Functional target for copper and zinc balance |
| ALT (paired with AST) | Below 25 U/L | Early sign of liver stress from copper or contaminants |
| Hair density by trichoscopy | No established target; track change from own baseline | Objective measure of benefit |
Cadence: Injectable use: copper, ceruloplasmin, zinc and liver enzymes at baseline; copper, ceruloplasmin and liver enzymes rechecked at 4–8 weeks, then every 3–6 months. Topical use: laboratory testing optional; baseline scalp photographs (ideally trichoscopy), repeated at 3 and 6 months, then every 6 months.