Tier C · Early / limited human evidence
GHK-Cu
A naturally occurring copper peptide with credible skin-repair biology and a much less certain injectable story.
Why researchers care
Potential human relevance
- Supports collagen and extracellular-matrix signaling in experimental systems
- Widely used in topical cosmetic formulations
- Studied in wound-healing and tissue-remodeling research
What the human evidence says
Evidence, not extrapolation
Topical copper-peptide use has a longer history than injectable GHK-Cu. Many strong mechanistic claims come from cell and animal studies rather than large modern clinical trials.
How to think about it
The Yooper Peptides take
Route matters. Evidence for a topical cosmetic ingredient does not automatically validate systemic injection claims.
Primary / authoritative reading