The real difference is capacity, not the bottle
Both Lansinoh glass bottle 4-packs share the same NaturalWave nipple, Air Ventilation System, and wide-neck design. The choice between 5oz and 8oz comes down to how much milk you typically serve per feeding and whether you want one set to cover both newborn and older-baby stages.
The supplied records do not list a minimum or maximum age for either size, so treat capacity as a practical guide rather than a rule. If you are unsure, start with the smaller set and add the larger size when your baby's intake grows.
5oz vs 8oz at a glance
- 5oz 4-pack: Best for smaller, more frequent feeds and for testing whether your baby accepts the NaturalWave nipple. Available with Extra Slow (Newborn) or Slow Flow nipples in the supplied variant evidence.
- 8oz 4-pack: Best when you routinely serve larger volumes or want to pump, store, and feed from the same bottle. The supplied variant evidence lists a 4-pack option; specific nipple flow variants are not confirmed in the supplied record.
- Shared features: Both sizes use the NaturalWave nipple, are BPA/BPS free, and are dishwasher safe on the top rack only. Both can be sanitized by boiling, provided parts do not touch the pot's bottom or sides.
What the 5oz set gives you
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Glass Baby Bottles 5oz (4 pack): Glass Baby Bottles 5oz (4 pack) is available with Extra Slow (Newborn) or Slow Flow Nipple variants. The newborn and slow-flow options make this the more natural first set if you are still establishing feeding and want to start with a slower flow.
Glass Baby Bottles 5oz (4 pack)
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Glass Baby Bottles 5oz (4 pack): The NaturalWave Nipple is 100% silicone and is clinically proven to reduce nipple confusion, according to the supplied catalog. If you are moving between breast and bottle, the nipple design is the same across both sizes, so capacity is the main variable.
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Glass Baby Bottles 5oz (4 pack): The Air Ventilation System reduces intake of air, a potential cause of colic or spit up. This feature is shared with the 8oz set, so it does not help you choose between sizes, but it is part of what you are buying in either pack.
What the 8oz set gives you
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Glass Baby Bottles 8oz (4 pack): Glass Baby Bottles 8oz (4 pack) is listed as a 4-pack in the supplied variant evidence. The larger capacity suits bigger feeds, but confirm the nipple flow you receive, because the supplied variant evidence does not list flow options for this size.
Glass Baby Bottles 8oz (4 pack)
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Glass Baby Bottles 8oz (4 pack): The wide neck is designed for a seamless transition between pumping, storing, and feeding breastmilk. If you pump directly into the bottle and feed from it later, the 8oz size reduces the need to split a larger pump session across two bottles.
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Glass Baby Bottles 8oz (4 pack): The bottle and nipple are BPA/BPS free, and the bottle is made from polypropylene plastic according to the supplied FAQ. These material and safety details are shared with the 5oz set, so they confirm consistency rather than separate the two sizes.
Care rules that apply to both sets
Dishwasher-safe on the top rack only. To extend the life of the NaturalWave Nipple, the supplied guidance recommends gentle handwashing. Both bottles and nipples can be sanitized by boiling, but keep parts away from the pot's bottom and sides to avoid melting.
Do not heat the bottle or breastmilk in a microwave. The supplied instructions warn that microwaving can create hot spots and damage breastmilk nutrients. Instead, warm milk in a container of warm water before transferring to a bottle if needed. Lansinoh does not currently make a bottle warmer, according to the supplied record.
How to choose your first set
- Start with the 5oz set if you are primarily breastfeeding and offering small, frequent bottles.: The Extra Slow (Newborn) and Slow Flow variants let you begin with a slower nipple flow while you and your baby settle into a routine.
- Choose the 8oz set if you pump larger volumes or want one bottle to carry a full feed.: The larger capacity is more practical when you routinely serve more milk per feeding, but check which nipple flow is included before you buy.
- Buy one 4-pack first, then add the other size when your routine demands it.: A single 4-pack gives you enough bottles to rotate through washing and sanitizing without committing to a full collection of one size.
What the supplied information does not tell you
The records do not state a recommended age or weight range for either bottle size, nor do they specify exact ounce capacity markings or whether the 8oz pack includes multiple nipple flows. If those details matter to your decision, check the product page or packaging before ordering. The absence of that information here is not evidence that the product lacks it.
