GHK-Cu

GHK is a tripeptide with the amino acid sequence glycyl-histidyl-lysine. It naturally occurs in human plasma, saliva, and urine. In plasma the level of GHK is about 200 ng/mL at age 20, but declines to 80 ng/mL by age 60. This decline in the GHK-level coincides with the noticeable decrease in regenerative capacity of an organism.