Comotomo Silicone Baby Bottles vs. NUK Simply Natural Glass Bottles

Comotomo Silicone Baby Bottles and NUK Simply Natural Glass Bottles both rank among the most recommended bottles in parenting forums and pediatrician offices. They share a common goal — making bottle-feeding feel closer to breastfeeding — but they take entirely different paths to get there.

Comotomo bet everything on silicone. The body is soft and squeezable, the nipple is wide and breast-shaped, and the whole thing bounces when your baby inevitably throws it off the high chair. It feels unlike any other bottle on the market.

NUK Simply Natural bet on glass. Borosilicate glass is chemically inert, non-porous, and see-through. Their multi-hole nipple is designed to release milk the way a breast does — from multiple points rather than a single opening.

We compared materials, nipple design, cleaning, durability, and price so you can pick the right bottle for your feeding setup — or decide you need both.

For more on how much your baby should be eating, check our baby feeding chart.

This is the decision that drives everything else. Both materials are safe. Both are BPA-free. But they behave very differently in daily use.

Medical-grade silicone (Comotomo) is soft, flexible, lightweight, and virtually unbreakable. It does not leach chemicals when heated. The tradeoff: silicone is porous at a microscopic level, which means it can absorb odors and stains over time — especially from breast milk fat. Most parents notice this after 3–6 months of heavy use.

Borosilicate glass (NUK) is completely non-porous and chemically inert. Nothing sticks to it, nothing leaches from it, and it looks brand new after months of use. The tradeoff: it's heavier, and while borosilicate is tougher than regular glass, it can still shatter on a hard impact. A silicone sleeve helps, but adds bulk.

If you feed primarily at home, glass is hard to beat on purity and cleaning ease. If you feed on the go, at daycare, or want a bottle your baby can eventually hold, silicone's weight and durability advantages are real.

Both bottles aim to reduce nipple confusion in breastfed babies, but they approach the problem differently.

Comotomo's nipple is wide, rounded, and shaped to resemble a breast. The idea is that a breastfed baby will accept it more readily because the latch position feels familiar. It has a single hole and comes in slow-flow and medium-flow options. The dual air vents sit at the base of the nipple to reduce colic.

NUK Simply Natural's nipple has an orthodontic shape (slightly flattened) with multiple tiny holes at the tip rather than one. This distributes milk across the baby's palate the way breast milk flows from multiple ducts. NUK claims this makes the feeding experience feel more natural even though the nipple shape itself differs from a breast.

There is no clinical consensus on which approach works better. Some breastfed babies take to Comotomo instantly and refuse NUK. Others do the opposite. If you're trying to maintain a breast-bottle combination, buy one of each before committing to a full set.

This is where glass pulls ahead decisively.

NUK glass bottles are transparent, so you can see any milk residue clinging to the walls. Glass is non-porous — nothing absorbs into the surface. A standard bottle brush and warm soapy water gets them spotless. They come out of the dishwasher looking new. After six months of daily use, a glass bottle looks and smells exactly like it did on day one.

Comotomo bottles have a wide-mouth opening (the widest in the industry), which makes them easier to hand-wash than most bottles. However, the opaque silicone body means you cannot see residue on the inner surface. Silicone can develop a slightly cloudy film or faint sour-milk smell after prolonged use. Regular sterilization with boiling water or a steam sterilizer helps, but it does not fully prevent odor absorption over time.

Both are top-rack dishwasher safe. Both can be sterilized by boiling. If ease of cleaning and long-term hygiene are top concerns, glass is the stronger choice.

NUK Simply Natural Glass Bottles are typically $2–$4 cheaper per bottle than Comotomo. Over a starter set of four bottles, that adds up to $8–$16 in savings — modest but real.

The bigger cost difference shows up over time:

• Glass lasts longer. A NUK glass bottle used for your first child will work perfectly for your second. Silicone degrades and absorbs odors, so most parents replace Comotomo bottles between children.
• Replacement nipples cost about the same for both brands ($5–$8 per two-pack). You will replace nipples every 2–3 months regardless of bottle brand.
• You may need silicone sleeves for NUK glass bottles ($5–$8 each) if you use them at daycare or on the go. This narrows the per-bottle cost gap.

For a single child, the total cost difference is small. If you plan to reuse bottles across multiple children, glass saves meaningful money over the long run.

If soft, squeezable, and drop-proof sounds right for your setup, the Comotomo Silicone Baby Bottles (~$14 per 8 oz bottle) are a parent favorite for good reason — the wide breast-like nipple helps breastfed babies transition, the body is nearly indestructible, and the lightweight design is perfect for daycare bags and travel.

If you want the cleanest, most chemically inert bottle you can buy, the NUK Simply Natural Glass Bottles (~$13 per 9 oz bottle) deliver — borosilicate glass that never stains or absorbs odors, a multi-hole nipple that mimics natural breastfeeding flow, and a lower price point that gets even better when you factor in reuse across siblings.

Our honest take: if you are unsure, buy one of each. Babies are opinionated. The best bottle is the one your baby will actually drink from without fussing.

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Comotomo Silicone Baby Bottles and NUK Simply Natural Glass Bottles are both excellent choices — they just solve different problems.

Comotomo wins on portability, drop-resistance, weight, breast-like shape, and ease of temperature handling. It is the better choice for on-the-go families and daycare.

NUK Simply Natural wins on material purity, cleaning ease, odor resistance, longevity, environmental impact, and price. It is the better choice for home feeding and parents who prioritize glass over plastic or silicone.

Many parents end up owning both — glass at home, silicone in the diaper bag. That is a perfectly reasonable approach.

If you are tracking feeds — which is especially helpful in the early weeks to make sure your baby is eating enough — tinylog makes it simple to log every bottle and spot intake trends over time.

• Baby Feeding Chart — How much your baby should eat by age
• Breastfeeding Positions — Finding the right hold for you and your baby
• Baby Spit Up — What's normal and when to call your doctor
• Baby Colic — Causes, soothing techniques, and when to seek help

• Comotomo.com. "Comotomo Baby Bottle — Product Information and Materials." 2026.
• NUK-USA.com. "NUK Simply Natural Glass Baby Bottles — Product Details." 2026.
• BabyGearLab.com. "Best Baby Bottles of 2026 — Lab Tested and Expert Reviewed." 2026.
• Wirecutter (NYT). "The Best Baby Bottles." nytimes.com/wirecutter, 2025.
• Consumer Reports. "Best Baby Bottles From Our Tests." consumerreports.org, 2026.
• American Academy of Pediatrics. "Infant Food and Feeding." aap.org, 2025.
• Mommyhood101. "The Best Baby Bottles of 2026, Tested & Reviewed." mommyhood101.com.

This guide is for informational purposes only. Bottle choice is a personal preference based on your baby's individual needs and feeding situation. If your baby refuses to feed or shows signs of an allergy or intolerance, consult your pediatrician.