Effects of a Red Clover-Chamomile Complex Extract Ampoule on Hairline Hair Density, Hair Shaft Thickness, and Product Usability

This study aimed to exploratorily evaluate the effects of applying a red clover-chamomile complex extract-containing ampoule to the hairline on hair density, hair shaft thickness, usability, and safety. A 4-week, single-arm, pre-post comparison human application study was conducted in 10 men and women aged ≥20 and <50 years who self-perceived decreased hairline hair density. Participants applied the test product to the hairline area twice daily. Hair density (hairs/cm²) and hair shaft thickness (μm) were measured at Week 0 (baseline), Week 2, and Week 4 using a digital scalp analyzer (trichoscope). Usability was assessed using a 5-point Likert-scale questionnaire comprising four domains: perceived hairline changes, product usability, safety, and overall satisfaction. Data were analyzed using the Wilcoxon signed-rank test. Hair density increased significantly from 91.0±28.8 hairs/cm² at Week 0 to 136.0±28.8 hairs/cm² at Week 4 (49.5% increase; p<.01). Hair shaft thickness increased significantly from 25.90±12.12 μm at Week 0 to 46.80±19.59 μm at Week 4 (80.7% increase; p<.01). In the usability assessment, the total score improved significantly from 4.17±0.37 at Week 2 to 4.71±0.18 at Week 4 (p<.01), and significant improvements were observed across all subdomains (p<.05). No adverse events related to the test product were reported during the study period. Taken together, 4 weeks of hairline application of the red clover-chamomile complex extract ampoule resulted in significant improvements in hair density and hair shaft thickness, along with high usability and favorable safety. As an exploratory pilot study, further randomized controlled trials including a control group are warranted to verify these effects.