Exposure to certain endocrine-disrupting chemicals (EDCs) can interfere with the normal function of the thyroid gland. Chemicals such as polychlorinated biphenyls (PCBs), bisphenol A (BPA), and certain pesticides have been shown to alter TSH levels. These substances can mimic or inhibit the action of hormones, leading to either increased or decreased TSH levels, which in turn affects the synthesis of thyroid hormones.
