Glass vs plastic baby bottles
Do I need to switch my baby bottles to glass?
The verdict
Glass, if switching is easy for you — this is the largest direct measurement in our database. Polypropylene bottles released 1.3–16.2 million particles per litre of prepared formula, and the driver was the hot-water step that formula preparation requires. Glass is unaffected by it.
These carry different evidence grades. Polypropylene baby bottle is grade A and Glass baby bottle is grade B. One component of our score is measured release, which only earns points where a laboratory has actually counted particles — so a product nobody has tested scores lower than an identical one that has been. Part of the gap you are looking at is a difference in how much anyone has looked. Why we do it this way →
Where they actually differ
| Polypropylene baby bottle | Glass baby bottle | |
|---|---|---|
| Measured release | 1.3–16.2 million particles/L of formula | No mechanism at the bottle; teat unmeasured |
| What drives it | Water at 70°C, sterilising cycles, shaking | Glass is unaffected by all three |
| Practicality | Light, unbreakable, cheap | Heavier and breakable; sleeves help |
| If you cannot switch | Cool the water in a glass jug before it meets the bottle | — |
Where this comparison stops being reliable
The study did not measure absorption or any health outcome, and its authors did not recommend skipping the 70°C step — the bacterial risk that step prevents is established and immediate, while the particle risk is not characterised. Cooling in a separate glass vessel gets you both.
The full picture on each
Does Polypropylene baby bottle have microplastics?
Yes, and this is the largest direct measurement in the whole database. Polypropylene infant bottles prepared to WHO sterilisation guidance released 1.3–16.2 million microplastic particles per litre of formula — driven by the hot-water step, not by the plastic alone.
Full score breakdown and sources →
Does Glass baby bottle have microplastics?
Almost nothing from the bottle. Glass is unaffected by the hot-water step that drives release from polypropylene, which is precisely the mechanism the Nature Food study identified. The silicone teat remains, and it is a much smaller contact surface.
Full score breakdown and sources →
Neither of these is what you own
A comparison is between two product types. The item in your cupboard has its own packaging, its own age and its own condition. Scan it and get the same five-component score for the actual object.
Scan what I actually have