Assessing skin product exposure, toxicity and efficacy of skin products using fluorescence lifetime imaging microscopy

Fluorescence Lifetime Imaging microscopy (FLIM) provides precise biochemical insights for accurate toxicity profiling of human skin and assessment of skin cell metabolic states under real-world exposure conditions. Melanin, crucial for skin color, serves essential physiological functions, including UV protection, thermoregulation, and radical scavenging. In our study, we conducted a 60- day topical application of an over-the-counter product to quantify melanin within participants’ skin layers. FLIM successfully isolated melanin signals, revealing a significant reduction in normalized melanin content in the basal layer. Additionally, analysis of cellular metabolic states showed no significant differences across all study groups.