“Regrettable Substitution”: Exposure to Popular BPA Replacement BPS and Breast Cancer

IMG_5527Article Author: Ellie Geldart, Biomedical Engineering Major, Class of 2023, POB Science Translator

When you see the label “BPA-free”, you may consider that product to be safer. However, this is not always the case. Bisphenol A is an endocrine-disrupting chemical (EDC), which means it interferes with normal hormone communication within our bodies. Exposure to this chemical can lead to negative health consequences, such as increasing your risk for breast cancer. A commonly used replacement for BPA is Bisphenol S (BPS) but current research is revealing that BPS could be just as, if not more, dangerous.

A recent study from February 2021 investigated the effects of BPS exposure on the weight and volume of breast cancer tumors (Zhao et al. 2021). This study exposed breast cancer tumors to 10 micrograms of BPS per kilogram of body weight and 100 micrograms of BPS per kilogram of body weight and compared that to a control breast cancer tumor. The researchers found increased breast cancer tumor growth and deterioration of breast tissue following exposure to BPS. 

This study also found that tumor growth has a nonmonotonic response to BPS exposure (Zhao et al. 2021). The breast cancer tumors exposed to 10 micrograms of BPS per kilogram of body weight grew faster than the tumors exposed to 100 micrograms of BPS per kilogram of body weight. Usually higher exposure is associated with greater effects but a nonmonotonic response occurs if greater effects are seen when there are lower levels of exposure to the chemical. This suggests that you may be more susceptible to the dangers of BPS at lower exposures than at higher exposures. 

Exposure to BPA is also dangerous at low doses, as shown in a study conducted in 2011 (Jenkins et al., 2011). The nonmonotonic dose-response of BPS and its ability to increase breast cancer proliferation is extremely similar to BPA, the chemical it was meant to replace. This is an example of “regrettable substitution”, in which a dangerous chemical (BPA) is replaced with an equally dangerous and often less studied chemical (BPS).

Chemicals like BPA and BPS are found in a variety of plastics, packaging, bottles, and cans. To avoid exposure it is important to avoid plastic packaging and receipts whenever possible. Opt for glass containers and bottles over plastic or aluminum. It is important to be aware of these chemicals, and understand how labels like “BPA-free” can be misleading so that we can protect ourselves by making safer choices.


Jenkins, J. Wang, I. Eltoum, R. Desmond, C.A. LamartiniereChronic oral exposure to bisphenol A results in a nonmonotonic dose response in mammary carcinogenesis and metastasis in MMTV-erbB2 mice Environ. Health Perspect., 119 (2011), pp. 1604-1609

Zhao C, Yong T, Zhang Y, Xiao Y, Jin Y, Zheng C, Nirasawa T, Cai Z. Breast cancer proliferation and deterioration-associated metabolic heterogeneity changes induced by exposure of bisphenol S, a widespread replacement of bisphenol A. J Hazard Mater. 2021 Feb 19;414:125391. doi: 10.1016/j.jhazmat.2021.125391. Epub ahead of print. PMID: 33652221.

Disclaimer: The information provided herein is the author’s opinion. Our authors are not scientists. We are not providing medical advice, but simply sharing publicly available information. When we reference data and databases, we do so with the caveat that most are only as good as the data they are based on. While POB strives to make the information as timely and accurate as possible, we make no claims, promises, or guarantees about the completeness, or adequacy of the contents of any site that is shared, and expressly disclaims liability for errors and omissions in the contents of these sites.  POB goes to great lengths to avoid declaring shared products as “safe” as there is no legal definition of the word “safe” at this time.


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