Bisphenol A (BPA) has a pretty bad rap. Exposure to the chemical has been linked to everything from breast cancer to declining male fertility. But, a new systematic review suggests its replacements aren't necessarily any better. The research, published recently in Environmental Health Perspectives, looked at previously-published studies of two common BPA substitutes: bisphenol F (BPF) and bisphenol S (BPS). The investigators (both employees of the nonprofit Endocrine Disruption Exchange) identified 32 papers of at least moderate quality that examined BPF or BPS. Taken together, their results indicate that BPF and BPS may act as endocrine disruptors by messing with hormones — similar to what BPA does. This included effects such as inducing uterine growth in rats, increasing the weight of rat testes, and disrupting reproduction in zebrafish. Based on their findings, the authors conclude that these two BPA substitutes are both "as hormonally active as BPA." However, the links between BPA, BPS, or BPF exposure and human health aren't totally clear. And, water bottles are just one of many BPA sources we come into contact with all the time. So, trying to avoid the chemical (and those similar to it) entirely is probably an exercise in futility. But, this study is a good reminder that just because something says it's "BPA-free," that doesn't necessarily mean it's good for you. If you're in the market for a plastic-free bottle, though, we've got a few options.