Can bisphenol S in BPA-free bottles lead to weight gain and pancreas damage?

What's actually in it

Bisphenol S (BPS) is the chemical that replaced BPA in many water bottles, baby bottles, food containers, and receipt paper. When a product says "BPA-free," there's a good chance it contains BPS instead. You'll also find it in canned food linings and plastic tableware.

BPS was supposed to be the safer option. But its chemical structure is very close to BPA, which is why researchers have been testing whether it causes similar problems in the body.

What the research says

A 2026 study in Mol Cell Endocrinol exposed male animals to BPS over a long period at doses meant to reflect everyday human contact. The results were surprising: the animals gained weight and developed obesity without eating a high-fat diet.

BPS also damaged the pancreas. The cells that make insulin, called beta cells, stopped working properly. When your pancreas can't make enough insulin or release it at the right time, blood sugar goes haywire. That's the same pattern seen in early type 2 diabetes.

The key finding was that BPS alone was enough to cause these changes. The animals ate normal food. They didn't overeat. The chemical itself pushed their metabolism in a harmful direction.

If you use BPA-free plastic bottles or containers daily, the BPS in them could be doing more than nothing. Glass and stainless steel don't contain any bisphenols at all, making them a cleaner choice for everyday use.