Copper content calculation
GHK-Cu is about 16% copper by weight, so a 50 mg vial contains roughly 8 mg of elemental copper. Spread over four weeks, that is not high relative to the adult oral copper upper limit of 10 mg daily.
The key difference between injection and oral intake
But injected copper bypasses the gut, which is where the body regulates copper absorption. When copper is taken orally, the gut adjusts absorption based on body copper levels. Injected copper goes directly into the bloodstream, bypassing this regulation.
Missing human data
No human study has measured what subcutaneous copper peptide injections do to copper levels over weeks. A 2016 cell study found GHK-Cu produced fewer toxicity markers than copper salts in skin cells at the same copper concentration. This says something about the chelate but nothing about a month of injections.
Wilson’s disease and other copper metabolism disorders
Anyone with Wilson’s disease or other copper metabolism disorders should avoid GLOW due to GHK-Cu. In these patients, copper excretion is impaired, and additional injected copper may increase the risk of copper accumulation.
Why this is concerning
It is currently unknown how copper levels change after weeks of injected copper peptide. That is concerning. In the absence of human data, any claim of “safety” lacks a basis.
Conclusion
The copper load in GLOW is an unstudied area. Understanding the difference between injected and oral copper is the first step in assessing this risk.