Quick Answer
Both glass and plastic baby bottles can be used safely when chosen and maintained correctly, but they have meaningfully different properties that make each better suited to different priorities and situations. Glass bottles are free from chemical leaching concerns, are easier to sterilise thoroughly, and are more durable over years of use. High-quality plastic bottles made from food-grade, BPA-free materials are safe for feeding, lighter, and more resistant to breakage. The choice depends on how you weigh safety, convenience, durability, and cost. This article covers the key considerations for each material so you can make an informed decision for your family.
The Chemical Leaching Question
The primary safety concern historically associated with plastic baby bottles was bisphenol A (BPA), an industrial chemical used in polycarbonate plastics that can leach into liquids, particularly when heated. BPA is an endocrine disruptor, meaning it can interfere with hormonal signalling. Following significant research into its effects, BPA was banned from baby bottles and sippy cups in the United States in 2012, the European Union in 2011, and in many other countries. Most reputable bottle manufacturers removed BPA from their products before the formal bans took effect.
The replacement chemicals used in BPA-free plastics (including BPS, BPF, and various phthalates) have attracted ongoing research attention, as some studies suggest they may have similar endocrine-disrupting properties to BPA, though the evidence base is less established. This is an active area of research rather than a resolved question, and current regulatory bodies consider BPA-free plastics used in food contact products to be safe under normal use conditions.
Glass contains no synthetic polymers and does not carry the chemical leaching concerns associated with plastics. For parents who want complete certainty about chemical exposure from bottles, glass eliminates this variable entirely.
Glass Baby Bottles
Advantages
- No chemical leaching: Glass does not contain BPA, BPS, phthalates, or any synthetic polymer. There is no risk of chemicals migrating from the bottle into the milk, regardless of temperature or sterilisation method
- Easier to sterilise thoroughly: Glass can withstand any sterilisation method, including boiling, steam sterilisation, and microwave sterilisation, without degradation. It does not absorb odours or residues over time the way plastic can
- Durability over time: Glass does not degrade, scratch, or cloud with repeated washing and sterilising. A glass bottle used correctly remains in essentially the same condition after two years as it was when new. Scratched or clouded plastic bottles can harbour bacteria in surface irregularities and should be replaced; glass does not present this issue
- Environmental footprint: Glass bottles last significantly longer than plastic and are recyclable. For families who use bottles for multiple children over several years, glass can be the lower-impact long-term choice
Disadvantages
- Weight: Glass bottles are heavier than plastic, which matters when a baby begins to hold their own bottle (typically from around 6 months) and when carrying multiple bottles in a change bag
- Breakage risk: Glass breaks when dropped, which creates a safety hazard and the immediate loss of the bottle. Many glass bottle brands offer silicone sleeves that protect against breakage and improve grip; these significantly reduce but do not eliminate the breakage risk
- Cost: Glass bottles are typically more expensive upfront than comparable plastic bottles, though the longer lifespan can make them cost-competitive over several years of use
Plastic Baby Bottles
Advantages
- Lightweight: Plastic bottles are significantly lighter than glass, making them easier for babies to hold independently and more convenient for travel and outings
- Breakage resistance: Plastic does not shatter when dropped, which is a meaningful practical advantage in the first year when bottles are frequently dropped on hard floors
- Cost: Good-quality plastic bottles are generally less expensive upfront than glass equivalents
- Availability of designs: The majority of bottle designs, nipple shapes, and venting systems on the market are available in plastic
Disadvantages
- Degradation with use: Plastic scratches, clouds, and degrades with repeated sterilising and washing. Scratched plastic surfaces harbour bacteria and are more difficult to clean thoroughly. Bottles should be inspected regularly and replaced when scratching or clouding is visible
- Chemical leaching uncertainty: While BPA-free plastics are considered safe under current regulatory standards, the science on replacement chemicals is ongoing. Leaching risk is highest when plastic is heated: avoid heating formula in plastic bottles in the microwave, and check that your sterilisation method is compatible with the specific plastic your bottle is made from
- Environmental footprint: Plastic bottles have a shorter useful lifespan and are less consistently recyclable than glass
Safe Use Practices for Both Materials
Whichever material you choose, the following practices apply:
- Never heat formula or breast milk in a plastic bottle in the microwave. Microwaves heat unevenly, creating hot spots that can scald a baby's mouth, and heat increases chemical leaching from plastics. To warm a bottle, place it in a bowl of warm water or use a bottle warmer
- Inspect bottles regularly for scratches, cracks, chips, or clouding. Replace any bottle that shows significant surface degradation, regardless of material
- Follow the manufacturer's sterilisation guidance, as some plastics are not compatible with all sterilisation methods (particularly steam sterilising at high temperatures). Glass is compatible with all sterilisation methods
- Replace nipples regularly (typically every 1 to 3 months depending on use) regardless of the bottle material. Silicone nipples degrade with use and repeated sterilising; a compromised nipple affects flow rate and hygiene
What About Silicone Bottles?
A third option is silicone baby bottles, made entirely or primarily from food-grade silicone rather than glass or plastic. Silicone is free from BPA and other plastics-related chemical concerns, is lightweight, flexible, and shatter-resistant, and tolerates a wide range of sterilisation methods. Silicone bottles are a smaller segment of the market than glass or plastic but are worth considering for parents who want a non-glass, non-plastic option. They tend to be more expensive than plastic and may not be available in as wide a range of designs.
The Emulait Glass Classic Bottle
The Emulait Glass Classic Bottle is made from high-quality borosilicate glass, chosen for its chemical neutrality, thermal resistance, and durability. Its breast-shaped nipple design supports a natural latch and paced feeding technique, whether used as the primary bottle or alongside breastfeeding. For parents who prioritise the absence of chemical leaching concerns and long-term durability, borosilicate glass is among the most robust material choices available.
Key Takeaway
Glass bottles eliminate chemical leaching concerns entirely, sterilise more thoroughly, and last longer but are heavier and can break. BPA-free plastic bottles are safe under current regulatory standards, lighter, and breakage-resistant, but degrade with use and carry unresolved questions about replacement chemicals. For parents who want certainty about chemical exposure, glass is the clearer choice. For parents who prioritise lightness, breakage resistance, and lower upfront cost, high-quality BPA-free plastic is a practical and currently accepted-safe option. Whichever material you choose, never heat in a microwave, inspect regularly, and replace when surface degradation is visible.
Parents Also Ask
How to Choose the Right Baby Bottle for Your Baby
How to Clean and Sterilise Baby Bottles the Right Way
Combo Feeding: How to Breastfeed and Formula Feed at the Same Time
This article is for informational purposes only and is not a substitute for professional medical advice. For guidance specific to your baby's feeding needs, consult your pediatrician or a qualified healthcare provider.