Fabric sits against your skin all day, but the fibre is only part of the story. A conventionally grown, heavily dyed, resin-treated cotton shirt is not obviously better than a plain untreated synthetic one.
What reaches your skin is the fibre plus everything done to it — dyeing, finishing, and any performance treatment. And it is the finishes, not the fibres, where most of the real exposure lives.
What to avoid, and why
Every performance claim on a clothing label describes a chemical finish. These four are the ones worth treating as flags:
- “Wrinkle-free,” “non-iron,” “easy-care.” Traditionally a formaldehyde-based resin cross-linked into cotton so it cannot crease. Because it is bonded rather than coated, it does not wash out. A recognised contact allergen and a classic cause of dermatitis at collar and cuffs.
- “Stain-resistant,” “water-repellent,” DWR. Historically PFAS chemistry — persistent compounds now restricted in several jurisdictions. Note that “PFOA-free” is not “PFAS-free.”
- “Antimicrobial,” “odour-resistant.” Usually silver-based. Contributes to antimicrobial resistance without clear household benefit, and washes into waterways. Merino solves the same problem with no treatment.
- Added flame retardants outside children’s sleepwear, where the rules work differently and are worth understanding properly.
What the labels actually mean
- OEKO-TEX Standard 100 — tests the finished fabric against a restricted substance list. Says nothing about organic content or how it was made. Class I is the strictest tier, for babies and toddlers.
- GOTS — requires organic fibre content and restricts processing chemistry, ruling out formaldehyde finishes and chlorine bleaching, with social criteria attached. The stronger of the two, but natural fibres only.
- bluesign — chemical input management, common in outdoor brands.
- Responsible Wool Standard / ZQ — animal welfare, including non-mulesed merino.
- “Eco-friendly,” “sustainable,” “conscious,” “natural” — entirely undefined, frequently a brand’s own internal programme.
One trap worth knowing: “GOTS certified cotton” is not the same as a GOTS certified garment. Certified fibre can still be processed and finished in ways the standard would not permit.
Where to focus
You do not need to replace a wardrobe. Prioritise by contact time and skin sensitivity.
- Highest: underwear, bras, base layers, sleepwear, socks, and anything worn by a baby or young child.
- Moderate: shirts and trousers worn against skin all day.
- Lowest: outerwear and anything worn over other layers.
Buying less and buying better does more here than a wholesale replacement. Secondhand clothing has the additional advantage of having already been washed many times.
The free improvements
- Wash new clothes before wearing them. Removes loose dye, sizing agents, and processing residue. The easiest change on this page.
- Buy clothes that wrinkle. Creasing is a reliable sign nobody treated the fabric to prevent it.
- Air dry-cleaned items outside the bag before wearing.
- Use a washing bag or filter for synthetics to cut microplastic shedding.
- Take a persistent rash seriously. Textile contact dermatitis is real, and finishes are a common cause.
In this guide
Deeper reads on fabrics, labels, and treatments.
