Dermal Exposure to Bisphenols and Their Analogs: A Systematic Review and Narrative Synthesis

Purpose of Review Dermal exposure to bisphenols is an underrecognized pathway of systemic uptake, but differences in study designs and measured endpoints complicate exposure assessment. This systematic review synthesizes 71 studies examining dermal transfer, skin permeation and retention, human toxicokinetics, and exposure modeling for bisphenol A (BPA) and its analogs. Recent Findings BPA has the strongest evidence for systemic dermal uptake, supported by controlled human and experimental studies, while occupational biomonitoring supports exposure relevance without isolating the dermal route. Human studies demonstrate delayed BPA absorption and partial avoidance of first-pass metabolism. BPS generally shows lower transdermal passage than BPA but substantial skin retention, whereas BPAF and TGSA exhibit appreciable permeation in human-skin experiments. Thermal paper remains the best-characterized source; textiles, hygiene products, and other consumer materials represent additional potential sources, although their dermal dose estimates rely largely on modeled migration and absorption assumptions. Summary Dermal exposure assessment requires compound- and condition-specific parameters that distinguish skin loading, retention, permeation, and systemic bioavailability. Lower permeability does not necessarily imply lower risk. Improved human toxicokinetic data, realistic migration measurements, and refined PBPK models are needed to strengthen exposure assessment and evaluation of bisphenol alternatives.