Halogenated Phenolic Ingredients of Household and Personal Care Products Modulate Thyroid Receptor Signaling

Endocrine-disrupting chemicals can interfere with thyroid hormone signaling and may contribute to adverse health outcomes. Among these, halogenated phenolic derivatives of household and personal care product (HPCP) ingredients are of increasing concern due to their structural resemblance to thyroid hormones. In this study, a comprehensive library of halogenated parabens, bisphenols, UV filters, and nonylphenols was evaluated for thyroid receptor (TR) modulatory activity using a GH3.TRE-Luc reporter assay. Halogenated bisphenol F derivatives displayed pronounced TR agonistic activity, with dichlorinated BPF emerging as the most potent agonist. In contrast, dihalogenated long-chain parabens, particularly dibrominated analogs, demonstrated antagonistic effects in the low micromolar range. Overall, our findings demonstrate that halogenation significantly influences TR modulation by phenolic HPCP ingredients, emphasizing the need for further investigation into their potential endocrine-disrupting impact.