Clinical effects of a 0.5% selenium sulfide shampoo on dandruff and scalp microbiota in adolescents: a prospective single-arm clinical study.

INTRODUCTION: This prospective, exploratory single-arm pilot study evaluated the clinical efficacy, safety, and scalp microecological effects of a 0.5% selenium sulfide shampoo in adolescents with dandruff. METHODS: Following a 2-week washout, 31 adolescents applied the shampoo three to four times weekly for 4 weeks. Investigator assessments, patient-reported pruritus scores, instrumental assessments (transepidermal water loss, stratum corneum hydration, sebum spot size), and scalp microbiome analysis were performed at baseline (week 0) and at week 4 (or week 2 for some measures). RESULTS: Investigator assessments showed significant improvements: median dandruff scores declined from 16 to 6, erythema scores from 12 to 2, total scalp oiliness scores from 153 to 127, and total hair lift scores increased from 107 to 122 at week 4. Patient-reported pruritus scores decreased from 109 at baseline to 60, 48, and 37 at weeks 1, 2, and 4, respectively (P<0.001). Instrumental assessments demonstrated reduced transepidermal water loss (35.66 ± 8.18 to 31.12 ± 4.36 g/m2·h, P < 0.01), increased stratum corneum hydration (30.49 ± 10.28 to 35.01 ± 9.64 a.u., P < 0.001), and decreased sebum spot size at week 2 (953.65 ± 892.50 to 692.33 ± 456.19 pixels, P < 0.05). Genus-level microbiome profiling revealed significantly elevated Cutibacterium abundance (P < 0.001), alongside reduced levels of Staphylococcus and Malassezia (both P < 0.01). No adverse events were reported. CONCLUSION: The 0.5% selenium sulfide shampoo significantly improved clinical symptoms of dandruff in adolescents, with favorable safety, barrier-protective effects, promoted beneficial compositional shifts in the scalp microbial community toward a healthier profile.