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Parenting

Cheat Sheet: What’s Inside Your Baby’s Diaper?

Coterie Diaper FAQ

NEW MODERN MOM

1/23/25

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Written by:

Barbara Mighdoll

This post is in partnership with Coterie. I only endorse products I believe in.

You’re careful about what goes on your baby’s plate and skin—but what about their diapers?

Your baby spends almost 24/7 in diapers during their early years. That’s a lot of time in contact with the materials and ingredients they’re made of, which is why understanding what’s inside them is so important.

I’ve gone down the rabbit hole—researching ingredients, decoding all those buzzwords, and figuring out what actually matters. 

This post is here to be your cheat sheet: to understand the claims, and give you the info to make the best, non-toxic choice for your little one.

TLDR: Coterie is my top top choice for diapers because of their commitment to safe, transparent ingredients and unmatched quality! Get 10% off your subscription now.

The basics—what’s in a diaper?

It’s understandable that diapers don’t always get much of a second thought—it’s easy to just want to get the change done and move on. But there’s actually a lot going on inside those tiny, absorbent layers.

Outer layer (cover):

Why it’s there: For waterproof protection and to prevent leaks.

  • Plastic based: Polyethylene or polypropylene. They’re made from petroleum-based plastics, which aren’t biodegradable.
  • Eco-friendly options: Plant-based fibers like corn or bamboo. Some materials, like bamboo viscose, involve heavy chemical processing.
  • Biodegradable layers: Some brands combine plant fibers with a biodegradable coating to create a partially eco-friendly outer layer.
  • Non-woven fabrics: A blend of natural and synthetic fibers (like cotton with a synthetic waterproof layer).

Absorbent core:

Why it’s there: To lock in moisture, prevent leaks, and keep your baby’s skin dry.

  • Key ingredient: Sodium polyacrylate (SAP) is used in most diapers because of its super absorbent properties that lock in moisture and prevent any leaks.
  • Is it safe: Yes—SAP is non-toxic, widely tested, and considered safe for use in diapers.
  • Other options: Some brands mix SAP with wood pulp, bamboo fibers, or even cotton to reduce synthetic materials.

Inner liner (touching baby’s skin):

Why it’s there: To create a soft, comfortable barrier between your baby’s skin and the absorbent core.

  • Material: Typically made from polypropylene or plant-based fibers.
  • Claims to watch for: Terms like “hypoallergenic” and “dermatologist-tested”. They sound reassuring but can be misleading.

What do those buzzwords really mean?

Diaper labels are full of claims that sound great, but it’s important to understand what they mean and deliver so you can feel confident in your choices.

TCF vs. ECF—bleaching processes

Why it matters: Bleaching is how materials like wood pulp are cleaned and whitened during production. Chlorine-based processes can leave behind harmful pollutants, like dioxins, which are better avoided.

  • TCF (totally chlorine free): No chlorine compounds used at all. If given the option, I feel safer using TCF diapers. *Coterie is one of few brands that are actually TCF.
  • ECF (elemental chlorine free): Uses chlorine dioxide instead of pure chlorine—not chlorine-free.

Hypoallergenic—what does it guarantee?

  • Meaning: The product is less likely to cause an allergic reaction—but no guarantees.
  • Reality check: There are no regulations governing this term, so it’s more of a marketing label.

Fragrance-free vs. unscented—is there a difference?

  • Fragrance-free: Contains no added fragrances.
  • Unscented: May include masking agents to hide odors, which can still irritate sensitive skin.

Myth-busting compostable diapers

Compostable and biodegradable diapers sound like a perfect solution for reducing waste, but sadly the reality isn’t so straightforward. If you’re looking to make sustainable choices, here’s what you need to know.

The greenwashing problem

Lots of brands claim their diapers are “biodegradable” or “compostable,” but these labels can be misleading. The truth is, most so-called compostable diapers require specific conditions—like industrial composting facilities—which aren’t widely accessible. And even then, not all parts of a diaper break down, leaving parents with unrealistic ideas about their environmental impact.

The hard truth about composting diapers

  • Issue 1: Human waste regulations make it illegal to compost soiled diapers in most places.
  • Issue 2: Industrial composting facilities often reject diapers because of contamination concerns.
  • Bottom line: No diaper is 100% compostable or waste-free, no matter what the label says.

What can you do instead?

  • Look for diapers made with sustainably sourced materials (wood pulp, bamboo fibers) to help reduce plastic use.
  • Choose brands with transparent ingredient sourcing.

Coterie is my top diaper brand recommendation

When it comes to diapers, I want something I can feel good about using every day—and Coterie checks all the boxes. 

  • Safe ingredients: Dermatologist-tested, and no added fragrances, dyes, lotions, parabens, and chlorine.
  • Eco-conscious materials: Made with 25% plant-based materials and sustainably sourced TCF wood pulp.
  • Unmatched absorbency: Using Coterie diapers, I personally have experienced fewer leaks and blowouts (which results in better sleep!) rare diaper rashes, and less stress when on-the-go with both of my kids. 

After trying just about every premium diaper brand out there, Coterie is hands down my choice.

Try Coterie Diapers Now!

✅ Safe for baby’s skin

✅ Eco-friendly materials 

✅ Super absorbent

✅ Soft and comfy

✅ Stress-free changes 

✅ Transparent ingredients 

✅ Convenient delivery

Get 10% off your subscription of Coterie Diapers ($81 for a month of diapers): EXTRA10

Author

This post may contain affiliate links including the Amazon Associates Program. When you make purchases through links in this post, I may earn a small commission at no extra cost to you.  I only endorse products I believe in.