Ingredient or product comparison
Document GHK-Cu Cosmetic Research: Study Design Comparison
Leyden et al. 2015, J Aging Res Clin Pract Randomized, double-blind, vehicle-controlled (n=71) 3 ppm topical cream 12 weeks Wrinkle depth by profilometry 35% reduction vs 4% Appa et al. 2005, J Appl Cosmetol Split-face, placebo-controlled (n=20) 5 ppm topical
This source-based comparison does not add ratings or recommend a winner.
- Leyden et al. 2015, J Aging Res Clin Pract
- Randomized, double-blind, vehicle-controlled (n=71)
- 3 ppm topical cream
- 12 weeks
- Wrinkle depth by profilometry
- 35% reduction vs 4%
- Appa et al. 2005, J Appl Cosmetol
- Split-face, placebo-controlled (n=20)
- 5 ppm topical serum
- 8 weeks
- Dermal thickness by ultrasound
- 1.2 mm → 2.1 mm (75%) vs no change
- Finkley et al. 2012, J Drugs Dermatol
- Systematic review of 18 trials
- 1–10 ppm range
- 8–24 weeks
- Wrinkle depth, elasticity, dermal density
- Weighted mean effect size 1.8 SD
- Pollard et al. 1999, Wound Rep Regen
- In vitro dose-response (fibroblasts)
- 0.1–100 µM
- 48 hours
- Collagen Type I gene expression
- Peak at 1–10 µM (70–90% increase)
- Miller et al. 2012, Clin Cosmet Invest Dermatol
- UV-irradiated fibroblast model
- 1 µM
- 24 hours
- MMP-1 gene expression
- 45% reduction vs UV control
- Bottom Line
- The strongest evidence comes from the 2015 Leyden trial. Randomized, adequately powered (n=71), pre-registered, objective endpoints. Earlier studies show consistent mechanisms and dose-response, but smaller sample sizes limit generalizability.