Peptide Skincare & BeautySkin science and ingredient guides

Ingredient or product comparison

Evidence Comparison by Route

Human clinical trials Multiple (skin aging, post-laser, collagen) None Human observational data Decades of cosmetic product use Community self-reports only Animal studies Wound healing models Lung fibrosis, emphysema, ACL repair, neuroprotection In vitro / cel

This source-based comparison does not add ratings or recommend a winner.

  • Human clinical trials
  • Multiple (skin aging, post-laser, collagen)
  • None
  • Human observational data
  • Decades of cosmetic product use
  • Community self-reports only
  • Animal studies
  • Wound healing models
  • Lung fibrosis, emphysema, ACL repair, neuroprotection
  • In vitro / cell culture
  • Collagen synthesis, fibroblast activation
  • Gene expression (4,000+ genes), anti-inflammatory
  • Mechanism clarity
  • High -- well-characterized skin depot effect
  • Moderate -- systemic pathways mapped in animal models
  • Dose-response data
  • Established in human studies
  • Established in animal models only
  • The bottom line: topical GHK-Cu has human-grade evidence for skin outcomes. Injectable GHK-Cu has promising preclinical evidence for systemic outcomes, with community adoption running ahead of published clinical validation.