GHK-Cu is not an approved drug for systemic use. Topical products follow their own cosmetic labeling; injectable use is investigational with no human dosing studies. The amounts below are commonly cited and anecdotal, not medically established. Any real decision belongs with a qualified clinician.
Overview
GHK-Cu "dosing" means two unrelated things. For topical products — the only form with human evidence — the relevant number is a concentration: commercial serums and creams typically label around 1–2% GHK-Cu, applied once daily. For injectable research preparations, community sources most often cite 1–2 mg subcutaneously per day or every other day — figures that come from anecdotal logs, not from any clinical trial. No injectable dose of GHK-Cu has ever been established as safe or effective in humans.
Common dosing pattern
Topical (the evidence-bearing form). Market norms cluster around 1% GHK-Cu for face serums, with specialty products claiming 2% or more; a deep blue color is the rough visual signature of meaningful copper-peptide content. The clinical trials that support skin claims — the 12-week facial studies reviewed in Pickart & Margolina (2018) — used proprietary creams whose concentrations were not standardized or always disclosed, so there is no study-backed "correct" percentage. Cell studies find activity at concentrations far below 1%, which suggests the market numbers are set by formulation practice and marketing, not by a dose-response curve (Pickart et al., 2015).
Injectable (the evidence-free form). Commonly reported schemas in community and vendor sources:
- 1–2 mg subcutaneously, once daily or every other day;
- runs of several weeks, often framed around skin or recovery goals;
- sometimes injected near a treatment area, on the untested assumption of a local effect.
There is no human pharmacokinetic or dose-finding study behind any of these numbers. For copper context: at ~16% copper by weight, 2 mg of GHK-Cu carries roughly 0.3 mg of elemental copper — small against the 10 mg/day oral upper limit, but delivered by a route that bypasses the intestinal regulation that limit assumes (NIH Office of Dietary Supplements).
How it is administered
Topically, GHK-Cu is applied as a serum or cream to clean skin, typically once daily; many routines separate it from vitamin C and strong exfoliating acids on chemical-compatibility grounds (a theoretical concern — see the main GHK-Cu page FAQ). It also appears in post-microneedling products and hair topicals.
Injectable preparations are sold as lyophilized powder that users reconstitute with bacteriostatic water and inject subcutaneously. A consistently reported feature is a stinging pain at the injection site — GHK-Cu has a reputation as one of the more uncomfortable peptides to inject, which is why community logs mention extra dilution and site rotation. That detail matters here mainly as a reminder that this is self-experimentation on an unstudied route of administration, not a refined protocol.
Why oversight matters
The gap between GHK-Cu's two forms is the whole story. A 1% cosmetic serum operates in a regulated product category, at low systemic exposure, with small human trials behind its claims. An injectable vial operates in no regulatory category at all: no manufacturing oversight, no verified purity or sterility, no human data on dosing, distribution, or long-term copper handling — and the one independent randomized trial of GHK-Cu products (post-laser, topical) found no objective benefit even in its home domain (Miller et al., 2006).
Anyone weighing systemic use is therefore working entirely from animal and cell data, with individual factors — copper status, liver health, medications, conditions like Wilson disease — that only a clinician who knows their history can evaluate.