THE EFFICACY OF 2% COPPER PEPTIDE (GHK-Cu) SERUM FOR EYEBROW HYPOTRICHOSIS: A RANDOMIZED, DOUBLE-BLIND, VEHICLE-CONTROLLED, SPLIT-FACE COMPARATIVE STUDY

Abstract

Background: Eyebrows contribute significantly to facial aesthetics, expression, and personal identity. Sparse or thinning eyebrow hair may negatively affect appearance and self-confidence. Copper peptides, particularly glycyl-L-histidyl-L-lysine copper complex (GHK-Cu), have demonstrated wound-healing, anti-inflammatory, and hair growth–promoting properties; however, evidence regarding their effectiveness for eyebrow enhancement remains limited. Objective: To evaluate the efficacy and safety of 2% copper peptide (GHK-Cu) serum for improving eyebrow hair growth and density. Materials and Methods: A randomized, double-blind, placebo-controlled, split-face clinical trial was conducted in 18 healthy participants aged 18–40 years. Each participant applied 2% GHK-Cu serum to one eyebrow and placebo serum to the opposite eyebrow twice daily for 12 weeks. Eyebrow hair count, hair diameter, and global photographic assessment scores (GPAS) were evaluated using standardized photographic assessments. Participant satisfaction and adverse effects were also assessed. Results: The GHK-Cu serum–treated side demonstrated significant improvement in eyebrow hair count and diameter compared with the placebo side, particularly at week 12. Hair count significantly increased from baseline on the treated side (p < 0.05), while no significant changes were observed on the placebo side. Hair diameter also showed significant improvement after 12 weeks of treatment. GPAS and participant satisfaction scores were significantly higher on the GHK-Cu–treated side throughout the follow-up period. No serious adverse effects or allergic reactions were reported. Conclusion: Topical 2% GHK-Cu serum was safe, well tolerated, and effective in improving eyebrow hair count, thickness, and overall appearance, suggesting its potential as a non-invasive cosmetic option for eyebrow enhancement.