Short to medium term use appears safe based on available evidence
GHK-Cu, short for glycyl-L-histidyl-L-lysine copper, is a "naturally occurring copper peptide made up of three amino acids glycine, histidine and lysine that are bound to a copper ion," said Lisa Young, a registered dietitian nutritionist and adjunct professor at New York University
Interestingly, 8 out of 10 GSTP-positive cancer cells used here were found to be proto-oncogene KRAS -mutated cells
This effect does not impact the quality or purity of the peptide
All described studies evaluating small intestinal permeability used a 5 or 6 h urinary collection to assess small intestinal permeability, which may have confounded the results since a large amount of the sugars were probably already localized in the colon by the end of the urine collection (33)
(Regentherapy) In more detail: FOXO4 is a member of the FOXO (Forkhead box O) transcription factor family, which plays major roles in stress response, metabolism, cellular longevity and homeostasis