Reflectance Spectroscopy for Noninvasive Evaluation of Hair Follicle Stage

In 2014, researchers conducted a study on 30 female C57BL/6 mice to evaluate hair follicle stages noninvasively using reflectance spectroscopy. They measured skin diffuse reflectance and analyzed melanin content, finding that reflectance was high during the telogen and early anagen stages, decreased during anagen progression, and increased again during catagen. Melanin content showed inverse patterns, with a 6% increase on day 5 and over 60% on day 11, followed by a decrease during catagen and reaching a minimum during telogen on day 23. These results, consistent with histological examinations, suggest that reflectance spectroscopy could be a valuable tool for monitoring hair follicle stages and evaluating hair regeneration treatments, with data supported by a sample size of n ≥ 9 for each measurement.