Peptide Skincare & BeautySkin science and ingredient guides

Ingredient or product comparison

GHK-Cu on Empty Stomach Safety: Evidence Comparison

Fasted state (>8 hours without food) 85–110 ng/mL at standard 2mg dose 30–45 minutes 0.8% (mild injection site erythema only) Fastest absorption, easiest to standardize across study cohorts. No meal timing coordination required Fed state (within 2 hours of mea

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

  • Fasted state (>8 hours without food)
  • 85–110 ng/mL at standard 2mg dose
  • 30–45 minutes
  • 0.8% (mild injection site erythema only)
  • Fastest absorption, easiest to standardize across study cohorts. No meal timing coordination required
  • Fed state (within 2 hours of meal)
  • 45–60 minutes
  • 0.9% (mild injection site erythema only)
  • Identical systemic exposure, slightly delayed peak. Acceptable if all subjects follow the same meal timing
  • Oral administration (not subcutaneous)
  • 5–12 ng/mL at 50mg oral dose
  • 90–120 minutes
  • 3.2% (gastric discomfort, nausea)
  • Severely reduced bioavailability due to gastric degradation and hepatic first-pass. Not comparable to injectable protocols