Cotton

Cotton is a natural fibre made of almost pure cellulose, harvested from the fluffy seed heads of the cotton plant. It's been spun into cloth for thousands of years and remains the most widely used natural fibre in the world. The fibre is soft, breathable, absorbs moisture well, and washes at high temperatures without damage — which is a quiet hygiene advantage over many synthetics.

Comfort, breathability, and washability. Cotton is gentle next to skin, doesn't trap heat the way many synthetics do, absorbs sweat rather than wicking it into odour-prone films, and survives hundreds of hot washes. It also takes dye well and is inexpensive at scale. That combination is why it dominates underwear, baby clothes, bedding, and towels — the items that spend the most hours against your skin.

100% cotton, cotton, combed cotton, ring-spun cotton, Pima or Supima, Egyptian cotton, organic cotton, GOTS-certified cotton. Watch for blends — "cotton-rich" or "cotton blend" usually means cotton mixed with polyester or elastane. The fibre content label (required on clothing in most countries) tells you the exact percentages.

Almost everywhere fabric is: t-shirts, underwear, socks, denim, baby bodysuits and sleepwear, muslins, bed sheets, duvet covers, towels, tea towels, flannels, cotton pads and buds, tote bags, and curtains. It's the default fabric for anything that touches skin for long periods, which is exactly why this app recommends it so often.

Not really from the fibre — cotton itself is about as benign as everyday materials get. The relevant exposure is from what's applied to it. "Wrinkle-free" and "easy-care" finishes use resins that can release small amounts of formaldehyde; new garments can also carry dye and finishing residues from the factory. These sit on the fabric surface and against your skin until washed. One wash removes most of the free residue, which is why "wash before wearing" is the standard advice.

Cotton is broadly the recommended choice during pregnancy — breathable, washable, and free of the additive and shedding questions that hang over synthetic fabrics. If you're stocking up on maternity wear or preparing baby clothes, plain cotton washed before wearing is a calm, low-effort default. Skin can become more sensitive during pregnancy, and cotton is generally the fabric least likely to aggravate that.

No concerns from the fibre itself. Cotton underwear is breathable and is sometimes suggested over tight synthetics for general comfort; evidence on underwear choice and fertility measures is limited and mixed, so treat that as a comfort preference rather than a health intervention.

Cotton is the standard recommendation for baby clothing, sleepwear, and bedding — soft, breathable, and hot-washable. Two practical notes: wash everything new before it goes on a baby, since their skin is thinner and they mouth their clothes; and for children's sleepwear, snug-fitting cotton is the common route to meeting flammability rules without chemical flame-retardant treatment. If a child has eczema, smooth 100% cotton is usually the gentlest everyday option.

No specific concerns — cotton remains a comfortable, easy-care choice at every age. For anyone with fragile or easily irritated skin, soft cotton bedding and clothing tends to be the kindest option.

Three things are well established. The cotton fibre itself poses no meaningful chemical exposure concern. Wrinkle-resistant finishes are based on formaldehyde-releasing resins, and free formaldehyde on fabric drops substantially after the first wash. And pesticide use in conventional cotton farming — a real environmental and farm-worker issue — does not generally translate into measurable residues on the finished garment, because processing removes most of it. So the honest picture is: great fibre, manage the finishes, and view organic cotton mainly as a farming and supply-chain choice.

Very low — cotton is on the reassuring end of everything this app covers. The one situation worth managing is unwashed "wrinkle-free" garments worn directly on skin, which has occasionally been linked to skin irritation in sensitive people. Washing before wear addresses it. There is no reason to feel uneasy about plain cotton.

Cotton usually is the safer alternative — it's what we suggest in place of polyester, acrylic, and other synthetics for skin-contact items. Within cotton, the upgrades are: GOTS organic cotton (restricts finishing chemicals as well as farm inputs), OEKO-TEX certified cotton (finished fabric tested against a residue list), and plain non-easy-care cotton over wrinkle-free versions. Linen and hemp are comparable natural-fibre choices; wool covers warmth and sleepwear.

The better question is how easy it is to choose — and the answer is very. Cotton is everywhere, at every price point, clearly declared on fibre labels. The only mild effort is reading the label to confirm 100% cotton rather than a blend, and skipping "easy-care" claims if you want to avoid resin finishes.

Make "wash before wearing" a household habit for everything new in fabric — clothes, bedding, towels, and especially anything for a baby. It takes no extra money, removes most finishing residues, and matters most for items that sit against skin all day or all night.

When this app says "choose cotton instead," this entry is the reason: it's a genuinely low-concern material that solves several synthetic-fabric questions at once. Buy 100% cotton with confidence, wash new items before first use, and reserve the organic or certified versions for where they matter most to you — typically baby items and anything worn next to sensitive skin.

NIEHS and ECHA cover formaldehyde in consumer textiles; GOTS and OEKO-TEX publish exactly what their certifications do and don't cover. See References below.