Insulin like growth factor 1 level is a poor diagnostic indicator of growth hormone deficiency Scientific Reports Frontiers Growth hormone insulin like growth factor I axis in health and disease states: an update on the role of intra portal insulin How GHK Peptide Works Signaling GHK acts as a switch for skin repair: Interacts with adenosine receptors reduces inflammation Activates MAPK ERK, PI3K Akt, TGF pathways Stimulates fibroblasts & keratinocytes boosts collagen, elastin Superhuman Healing Part 2: Fixing GH & Peptide Misconceptions The GH IGF 1 axis in ageing and longevity Nature Reviews Endocrinology