ghk cu hair growth timeline 2% GHK-CU Copper Peptide Serum for and Scalp Care – Seraphime cu and ahk Boost Hair Health with GHK-Cu

You can see the effects on hair loss below - the mouse on the left has been treated with the peptide, and the one on the right hasn't: What makes this study particularly intriguing is the way the peptide seems to reverse the symptoms of ageing that have already occurred, demonstrating how lost fur in mice can be regrown

And while it may play a role, its not the whole story

doi: 10.1016/j.tips.2020.02.004 14 BenderAHaganKEKingstonN

That said, in humans the data are less robust than for some other sleep interventions, so effective depends on how you define it (improvement vs complete resolution of poor sleep quality)