are there any known side effects of using ghk-cu Peptides: Unlocking the Copper Peptide Revolution in Skin Care GHK-Cu for Hair Growth: Before
Description
And a mild histamine-like inflammatory response can occur in skin not used to active peptide signalling

The Cochrane database of systematic reviews , (12), CD007769

Additionally, peptides should be kept in tightly sealed containers for example vials to protect them from moisture and air exposure, which can compromise their quality
J Hum Lact
