is ghk-cu a naturally occurring human peptide - for Collagen, Healing & Anti-Aging Neuropeptide GHK-Cu: The Copper Peptide
Description
In other words, they speed up your body's metabolism when it comes to how fat is processed

Chitnis T, Weiner HL

If you have it or dont know what it is, you should have yourself checked as soon as possible
Some of these issues could be alleviated with robust human-based research, followed by FDA approval if warranted

Diarrhea and headache

Inhibition of Tumor Growth and Invasion by a Four-Kringle Antagonist (HGF/NK4) for Hepatocyte Growth Factor