What Is GHK-Cu (Copper Peptide)? Dosage & How to Track It

What GHK-Cu is and how it works

GHK-Cu is three amino acids — glycine, histidine, lysine — bound to a copper ion, and unlike most compounds in this library, it isn’t a lab invention: it’s a peptide your own body makes and circulates naturally, first isolated from human plasma in the 1970s. Plasma levels are highest around age 20 and decline steadily after that — by around age 60, levels are roughly a third to a half of where they started, a decline that tracks with the visible signs of skin aging researchers have connected it to.

Mechanistically, GHK-Cu has a broad footprint: it activates genes involved in collagen and elastin production, has meaningful antioxidant activity, promotes new blood-vessel growth (angiogenesis), and dials down inflammatory signaling. Human studies — not just animal models — have shown measurable improvements in skin thickness, wrinkle depth, and collagen density from topical application, which is why it’s a mainstream, well-established skincare ingredient rather than a fringe one.

The important distinction: topical GHK-Cu (creams, serums) has real human evidence behind it and is a recognized cosmetic ingredient. Injectable GHK-Cu protocols — dosed systemically for a broader wound-healing or tissue-repair effect — are considerably less studied in humans and are community-derived, not FDA-approved for injection.

Typical dosing & reconstitution

For injectable use, GHK-Cu ships lyophilized and is reconstituted with sterile or bacteriostatic water. Community protocols run 1–2 mg per injection, most commonly five days a week (weekdays on, weekend off) or three times weekly, titrated up gradually over eight to twelve weeks.

Reconstitution differs meaningfully by vial size:

At 16.67 mg/mL, a 1.5 mg dose is 9 units. Because the 100 mg vial concentrates to roughly double that, the same 1.5 mg dose is only about 4.5 units — worth checking with the calculator before you draw up, since the two common vial sizes aren’t interchangeable unit-for-unit.

Half-life & what it means for frequency

GHK-Cu clears quickly from circulation — it’s rapidly bound by albumin and metabolized, on the order of minutes rather than hours — which tracks with why it’s dosed frequently (several times a week) rather than weekly. There isn’t a depot effect keeping it active between injections.

This short systemic half-life is part of why topical application remains the dominant, best-evidenced use case: applied to skin, it can act locally and repeatedly without needing to persist in the bloodstream, whereas injectable use is chasing a more systemic, harder-to-sustain effect.

What to track & common side effects

Topically, GHK-Cu is well tolerated with a long track record in skincare. Injected, the most common reports are local — injection-site redness or irritation. Because it’s pro-angiogenic (it promotes new blood-vessel growth), the same cancer-history caution that applies to BPC-157 applies here.

What’s worth tracking: the injection days each week (since it’s not a simple daily habit), and whatever skin, wound, or hair outcome you’re targeting — visible skin changes in the studies that exist took weeks to show up, so a photo-and-log routine over time is more useful than day-to-day comparison.

Frequently asked questions