Bisphenol A: A Scientific Evaluation

Michael A. Kamrin, PhD

In This Article


Although BPA is a component of a number of common consumer products, including those that come into contact with food, exposures of humans of all ages are very limited. The emergence of studies that provide more direct measures of these exposures reveals that early estimates of exposures based on more indirect approaches overstated human intake.

After thorough consideration by independent scientific panels of claims that low doses of BPA cause endocrine-related effects, such as developmental and reproductive toxicities, these panels have come to the conclusion that no such low-dose effects have been established. Although not all of the uncertainties about the toxicity of BPA have been resolved, it currently appears that the most scientifically valid assessment of the toxicity of BPA is one based on high-dose rodent studies, which show that very high exposures -- up to doses that are toxic to the mother -- are required to cause reproductive or developmental effects.

Government agencies have extrapolated the NOELs in these high-dose rodent studies to calculate acceptable intake levels in humans, assuming that humans are more sensitive to the effects of BPA than rodents. Comparisons of these acceptable levels with the estimated intake levels reveals that the intakes are 100-1000 times lower than acceptable intake values, leaving a large margin of safety.

Recent studies of the metabolism of BPA in humans and the toxicity of its main metabolite indicate that the margin of safety is even higher than the above analysis suggests. This research reveals that humans are even less likely than rodents to exhibit toxic effects from BPA exposure, because humans metabolize this compound more rapidly and completely than rodents. In addition, studies have shown that the main metabolite of BPA does not bind to the estrogen receptor, so that BPA metabolism reduces even further the likelihood of any endocrine effects mediated by receptor binding.

Thus, the evidence that has been collected in recent years coupled with experience from decades of occupational exposures indicates that the risk of BPA to humans of all ages is very low. It is thus very unlikely that humans, including infants, will suffer any adverse consequences, including endocrine-related effects, from current exposures to BPA in food, drink, or other consumer products.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.