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“BPA-free” gets treated like a safety stamp, but it isn’t one. It only means one chemical, BPA, was left out. What most people don’t realize is that when companies remove BPA, they usually replace it with a close chemical cousin, like BPS (Bisphenol S) or BPF (Bisphenol F). Research about the effects of these substitutes is still ongoing, but multiple independent studies are pointing towards results that show similar biological activity to BPA. As a result, a growing number of toxicologists are calling this kind of substitution “regrettable” rather than protective.

Let’s break down what’s actually going on, what the research says, and what to actually look for instead of just the “BPA-free” label

What “BPA-Free” Actually Means (And Doesn’t)

What the Research Actually Says and Why This Matters for Our Kids

Here’s a detail that surprises most parents: in 2012, the FDA amended its food additive regulations to no longer allow BPA-based polycarbonate resins in baby bottles and sippy cups. It’s worth being precise about what that actually was: by the FDA’s own account, the change was based on manufacturers having already abandoned BPA in these products, not on a new safety finding. The agency has stated plainly that the amendment “is not based on safety” (FDA).

A 2022 short editorial published in Clinical and Experimental Pediatrics looked at what happens after BPA gets phased out, and the findings are worth knowing. Bisphenol F and bisphenol S, the two most common replacements, can leach out of “BPA-free” plastic in much the same way BPA did. Both seemed to act as endocrine disruptors, meaning they interfere with the body’s natural hormone signals, and researchers have linked this kind of disruption to a range of health concerns (Jeon, 2022).

It’s not just bisphenols, either. The review points out that other BPA-free materials, like polypropylene, polyethersulfone, and silicone, aren’t automatically in the clear. Each one can shed its own chemical byproducts under the right (or wrong) conditions.

And those conditions are exactly what a baby bottle goes through every single day. Leaching gets worse with heat, so boiling for sterilization, running bottles through the dishwasher, or heating in the microwave all increase the amount that ends up in your baby’s milk. Harsh detergents make it worse too.

This is really the heart of the “BPA-free” problem. It’s not that the label is lying: it’s that the label only ever answers one narrow question.

Instead of Relying on a “BPA-free” Label, Look at the Material Quality Itself

Here’s What Also Really Matters:

• Limit heat exposure on any plastic product, regardless of what the label says. Heat is one of the main triggers for chemical leaching, so this matters no matter which plastic you’re using
• Look for PPSU. It’s manufactured differently from conventional BPA-free plastics and doesn’t rely on the same substitution chemistry that BPS and BPF are part of. That said, PPSU’s own manufacturing process still involves bisphenol-based building blocks (more on that below), so it’s worth asking any brand directly what testing they’ve done rather than assuming “PPSU” alone settles the question.
• Or, choose food-grade stainless steel (SUS 304/316) for the parts that actually touch liquid, one of the most stable materials used in food contact products. Just know that most stainless cups still include plastic or silicone components too, like lids, handles, or straws, so it’s worth checking what those specific parts are made of.

Our Top Picks for PPSU and Stainless Steel Bottles That Actually Deliver

Both options below are part of the PPSU and stainless cups we carry at Onzenna, and both skip the substitution problem for the parts that actually touch your baby’s drink.

Choosing With Confidence

A label can only tell you so much. The safest choice isn’t the one with the most reassuring word on the front, it’s the one you actually understand, material and all.

That’s really what this whole guide comes down to: knowing what to check for, instead of what to take on faith.

Grosmimi builds every product with that same transparency in mind, telling you plainly what each part is made of, from the PPSU or stainless steel body down to the straw and seals, so nothing is left for you to guess at. That goes for more than straw cups, too. From bottles to feeding tools to on-the-go cups, the same standard applies across the entire line.

FAQ

Is BPA actually banned anywhere?
Yes, though the timeline is more nuanced than a single effective date. The European Commission adopted a ban on BPA in food contact materials on December 19, 2024, based on the European Food Safety Authority’s finding that current BPA exposure levels pose a risk to consumers of all ages. For most products, there’s an 18-month phase-out period, meaning full compliance is expected around mid-2026 rather than an immediate cutoff (European Commission; EFSA, 2024).

Are BPS and BPF definitely proven harmful?
Not definitively. Research is still ongoing, and effects vary by study and dose. What’s well-established is the pattern: multiple independent studies keep finding similar biological activity to BPA, which is why many toxicologists call this substitution “regrettable” rather than protective.

Sources

• FDA, “Bisphenol A (BPA): Use in Food Contact Application”: https://www.fda.gov/food/food-packaging-other-substances-come-contact-food-information-consumers/bisphenol-bpa-use-food-contact-application
• NPR – FDA Bans Chemical BPA From Sippy Cups And Baby Bottles: https://www.npr.org/sections/thesalt/2012/07/17/156916616/fda-bans-chemical-bpa-in-sippy-cups-and-baby-bottles
• Clinical and Experimental Pediatrics – Bisphenol A leaching from polycarbonate baby bottles into baby food causes potential health issues: https://pmc.ncbi.nlm.nih.gov/articles/PMC9441614/
• The European Commission – Commission adopts ban of Bisphenol A in food contact materials: https://food.ec.europa.eu/food-safety-news/commission-adopts-ban-bisphenol-food-contact-materials-2024-12-19_en
• Grosmimi PPSU Straw Cup product page (materials, care instructions, replacement guidance), Onzenna: https://onzenna.com/products/ppsu-straw-cup-10oz-300ml
• Grosmimi Stainless Steel Straw Cup product page (materials, care instructions, replacement guidance), Onzenna: https://onzenna.com/products/grosmimi-stainless-steel-straw-cup-with-flip-top-10oz-300ml