Are typical human serum BPA concentrations measurable and sufficient to be estrogenic in the general population?

Mammalian estrogen receptors modulate many physiological processes. Chemicals with structural features similar to estrogens can interact with estrogen receptors to produce biological effects similar to those caused by endogenous estrogens in the body. Bisphenol A (BPA) is a structural analogue of estrogen that binds to estrogen receptors. Exposure to BPA in humans is virtually ubiquitous in industrialized societies, but BPA is rapidly detoxified by metabolism and does not accumulate in the body. Whether or not serum concentrations of BPA in humans are sufficiently high to disrupt normal estrogen-related biology is the subject of intense political and scientific debate. Here we show a convergence of robust methods for measuring or calculating serum concentrations of BPA in humans from 93 published studies of more than 30,000 individuals in 19 countries across all life stages. Typical serum BPA concentrations are orders of magnitude lower than levels measurable by modern analytical methods and below concentrations required to occupy more than 0.0009% of Type II Estrogen Binding Sites, GPR30, ERα or ERβ receptors. Occupancies would be higher, but ≤0.04%, for the highest affinity receptor, ERRγ. Our results show limited or no potential for estrogenicity in humans, and question reports of measurable BPA in human serum.