Is it necessary to cycle on and off of every peptide? The answer may not be as simple as you think, and it depends on *why* the peptide is being used. The Is it necessary to cycle on and off of every peptide? The answer may not be as simple as you think, and it depends on *why* the peptide is being used. The GHK Cu: The Peptide That Supports Healthy Aging GHK Cu (copper peptide) is naturally occurring in the body and plays a role in supporting skin health, collagen production, and tissue repair. As I ran GHK Cu for 12 months so you dont have to (here are the results) GHK Cu The Doctors Protocol in current Clinical Use , DISCLAIMER, The information shared in this video is for educational and informational purposes only and is based on research, and general