The most sustainable fabrics — honestly

There is no perfect fabric

If you have ever stood in a shop reading a composition label and hoping it would settle the question, I am sorry: it will not. A fibre is one input among several, and it is rarely the decisive one.

Four things determine a garment's footprint, and only the first is on the label:

• What it is made of — the fibre, and how it was grown or manufactured.
• How it was made — dyeing and finishing are water- and chemical-intensive, and invisible on the label.
• How long you keep it — usually the biggest lever of the four.
• How you wash it — temperature, frequency, and whether it goes in a tumble dryer.

A linen shirt worn twice and tumble-dried has a worse record than a polyester one worn two hundred times and line-dried. Fibre choice matters. It is simply not the whole story, and the industry finds it very convenient when we think it is.

The lower-impact naturals

These have a genuinely good case — each with a caveat, because the caveats are the useful part.

Linen

Flax grows well in cool European climates with little irrigation and few inputs, and the fibre is strong — good linen outlasts most things in a wardrobe. Caveat: it creases, which leads some people to press or dry-clean it more than they need to.

Hemp

Fast-growing, needs little water and few pesticides, improves soil structure, and is extremely durable. Caveat: processing hemp into a soft fibre can involve chemical retting, and the supply chain is small enough that transparency varies.

Organic cotton

Grown without synthetic pesticides or fertilisers, which matters for the people in the fields as much as for the soil. Caveat: it is still a thirsty crop with a large land footprint, and yields are typically lower per hectare. Organic solves some cotton problems, not all of them.

Tencel (lyocell)

Made from wood pulp in a closed-loop process that recovers most of the solvent, and it feels lovely. Caveat: the sustainability rests on the specific producer and where the wood came from — "lyocell" alone tells you less than the brand name Tencel does.

The genuinely complicated ones

Conventional cotton

Comfortable, breathable, familiar and repairable. Also pesticide- and water-intensive in many growing regions. Worth knowing that more than half of the water associated with clothing bought in the UK comes from countries and watersheds already under water stress (WRAP).

Wool

Durable, biodegradable, naturally odour-resistant, and needs washing far less often than almost anything else — a real use-phase advantage. Against that: methane from sheep, and animal-welfare practices that vary widely. Certification schemes exist and are worth looking for.

Recycled polyester

The one with the most enthusiastic marketing and the most need for care. It diverts existing plastic, needs less water than cotton, and makes hard-wearing garments. Two honest problems:

• It sheds microplastics. Every wash releases synthetic fibres into the water system. Washing less, cooler, on shorter cycles and in fuller loads reduces it; a filter bag helps. It does not disappear.
• It is usually made from bottles, not clothes. Textile-to-textile recycling is still rare, so most recycled polyester takes plastic out of a closed bottle loop and puts it into a garment that is much harder to recycle again.

None of that makes it a bad choice — for outerwear and activewear it is often the sensible one. It makes it a trade-off rather than a solution.

Viscose and rayon

Also from wood pulp, but conventional viscose production is chemically harsh and has been linked to deforestation. Drapes beautifully; ask where the pulp came from.

Durability beats fibre

Extending the active life of clothing reduces its carbon, water and waste footprint by up to 20% (WRAP, Valuing Our Clothes). No fibre swap available to you at the till will beat that.

So the practical questions, in order: will this survive fifty washes? Can it be repaired? Will I still want it in three years? A well-made garment in a mediocre fibre, kept for a decade, beats a virtuous fibre worn twice.

The same logic runs the other way — the garment with no footprint at all is the one already hanging up. How cost per wear works →

What certifications actually mean

Useful, not conclusive. GOTS covers organic fibre content plus environmental and social criteria through processing, which makes it one of the more meaningful marks. OEKO-TEX tests for harmful substances in the finished textile — a chemical-safety mark, not a sustainability one. B Corp assesses the whole company, not the garment.

All of them cost money to obtain, which means small makers doing excellent work often have none. Absence of a logo is not evidence of harm.

How the app helps

Closet Remix estimates the impact of each piece by fabric type, so you can see how the mix in your own wardrobe stacks up rather than guessing. And the brand directory researches materials as one of its criteria — so when you do need something new, the fibre question has already been asked.

So which fabric should you buy?

The one already in your wardrobe. After that: the best-made version you can afford, in a fibre suited to how the garment will actually live, from a brand that will tell you where it came from.

Less satisfying than "buy linen". Rather more true. See our full guide: how to dress more sustainably →

Common questions