Clinical Observational Study on Changes in Skin Physiological Parameters Following Ablative and Non-Ablative Fractional Laser Treatment at Different Doses

This clinical observational study investigates the dose-response relationship between laser energy intensity and skin damage/repair by applying different parameter sets of fractional ablative (CO2) and non-ablative (M22) lasers to the inner forearms of approximately 20 healthy Chinese female volunteers (aged 18-60, Fitzpatrick skin types III-V) in a single-center, self-controlled design. Each participant receives both laser types on contralateral arms, with four distinct energy/density combinations per laser applied to separate test areas, and the dynamic skin responses are evaluated at baseline, immediately post-treatment, and at 30 minutes, 1, 2, 3, 4 hours, 7 days, and 10 days thereafter through clinical assessments (edema, erythema, etc.), standardized photography, high-frequency ultrasound (Dermascan), and objective instrumental measurements of skin color (Chromameter CM26dG), melanin/hemoglobin (Mexameter MX18), and barrier function (TEWL via Vapometer). The collected data will be analyzed using descriptive and comparative statistical methods to characterize the acute injury and recovery profiles, aiming to establish a foundational model for future post-procedure cosmetic intervention research.