GHK-Cu stands for glycyl-L-histidyl-L-lysine complexed with copper(II), a small tripeptide that your body produces naturally
This is in agreement with a recent study reporting a decreased number of duodenal serotonin containing endocrine cells in FD patients ( Several 5-HT receptor agonists/antagonists, such as cisapride (5-HT4 agonist, 5-HT2, and 5-HT3 antagonist), tegaserod (5-HT4 and 5-HT1 agonist, 5-HT2a/b antagonist), mosapride (5-HT4 agonist, 5-HT3 antagonist) and revexepride (5-HT4 agonist) have been evaluated for the treatment of dyspepsia and gastroparesis, although not all studies show efficacy (114116)
This is called the milk-letdown reflex or milk ejection reflex
The vial goes cloudy, the peptide aggregates, and the dose is non-functional
Within minutes, you're down a rabbit hole of injection techniques