The Verdict List

Comparison

Glass vs PPSU baby bottles

Last reviewed

Researched & reviewed by The Verdict List Editorial Team

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The short version

Glass and PPSU are both reasonable bottle bodies, and neither makes a plastic-free bottle. A glass body avoids the polypropylene-body shedding mechanism measured in a 2020 study, which did not test glass bottles. But the rings, caps and vents on the glass bottles we reviewed are often polypropylene or other polymers. PPSU is light, shatter resistant and tolerates high heat, but it is a polymer, and we found no test of the Hegen bottle itself.

Side by side

Where they differ

What the body is
The glass bottles use borosilicate or thermal-shock-resistant glass. Some of those statements are family-level, from Philips and Dr. Brown's, and the Evenflo glass type is not stated. PPSU is polyphenylsulfone, a high-performance polymer used for premium bottle bodies. It is formally composed of bisphenol S and 4,4'-dihydroxybiphenyl, so its chemistry is not unrelated to bisphenols.
Strengths and trade-offs of the body
A glass body has no polymer bottle body, resists chemicals strongly and lets you see residue, but it is heavier and breakable. A PPSU body has high heat resistance, is light and shatter resistant, and keeps its shape.
The rest of the bottle
A glass body does not make a system plastic-free. Lifefactory's cap, ring and stopper are polypropylene, and the Dr. Brown's anti-colic vent adds polypropylene and thermoplastic-rubber parts with narrow passages to clean. The Hegen bottle pairs its PPSU body with a silicone nipple.
What testing found
A 2018 study of five PPSU baby-bottle types did not detect bisphenol S above 0.3 mg/kg of polymer, found 4,4'-dihydroxybiphenyl at 1.7 to 15.5 mg/kg, and found migration into a milk simulant within the limits and thresholds its authors applied. That is not a statement about every current bottle. Our research also records a 2025 study reporting particle release from tested PPSU bottles that rose with temperature. We could not re-read its abstract, and its products cannot be assigned to a named US bottle. For the glass systems we reviewed, we found no exact-product migration or particle data.
Verdicts in this category
Current published verdict totals are generated above from the same category records as each product page. A Trade-offs verdict may reflect extra polymer components or unresolved material disclosures; read each bottle's evidence for its specific reason. The Hegen PPSU bottle has Trade-offs because its body is a polymer and we found no Hegen-specific test.

How to read this comparison

This page compares materials, not a winner. Each group lists the bottles we reviewed with that body material, and the table is built from the same research as each verdict page. A bottle’s verdict depends on the whole fluid path, meaning the body, nipple, ring, cap and vent, not on the body material alone. That is why some glass bottles are rated Trade-offs and the PPSU bottle is too.

A finding about a material does not describe a specific bottle unless that bottle was tested. Read each bottle’s verdict page for its fluid path and for what we could not verify.

Sources

  1. Microplastic release from the degradation of polypropylene feeding bottles during infant formula preparation, Li D et al., Nature Food (2020)
  2. Polyphenylsulfone (PPSU) for baby bottles: a comprehensive assessment on polymer-related non-intentionally added substances (NIAS), Eckardt M, Greb A, Simat TJ, Food Additives & Contaminants: Part A (2018)
  3. Microplastics release from infant feeding bottles and milk storage bags, Zhao L et al., Food Control 168 (abstract not re-verified in our research) (2025)

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