If you have been sourcing from gray-market or "research use only" vendors: The risks are real and not hypothetical contamination, inaccurate dosing, and the absence of any clinical oversight
This can include anti-inflammatory medications and physical therapy
The copper coordination geometry is the defining structural feature of GHK-Cu
J Pharmacol Sci 95:1926 Prkacin I, Separovic J, Aralicia G, Perovic D, Gjurasin M, Lovric-Bencic M, Stancic-Rokotov D, Staresinic M, Anic T, Mikus D et al (2001) Portal hypertension and liver lesions in chronically alcohol drinking rats prevented and reversed by stable gastric pentadecapeptide BPC 157 (PL-10, PLD-116), and propranolol, but not ranitidine
The two share the histidine-anchored coordination chemistry but have different specific binding geometries, binding affinities, and biological characterizations
This can aggravate brain fog rather than relieve it