Mechanisms of Disease: metabolic effects of growth hormone and insulin like growth factor 1 Nature Reviews Endocrinology GHK Copper Peptide for Skin Regeneration 1 As we age, the signals that tell our skin to repair and regenerate gradually decline. This can lead to thinner skin, slower healing, reduced elasticity, Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives Before vs. after 3 months of GHK Cu peptide therapy smoother texture, more even tone, and skin that looks healthier overall. Small peptide, big difference A Theoretical Link Between the GH IGF 1 Axis and Cytokine Family in Children: Current Knowledge and Future Perspectives Effects of Copper Tripeptide on the Growth and Expression of Growth Factors by Normal and Irradiated Fibroblasts Jeffrey D. Pollard, Susan Quan, Thomas Kang, R. James Koch, 2005