Sustainable fabrics: a guide to what your clothes are made of

The most sustainable garment is the one you already own, cared for and worn for as long as possible. When you do buy, knowing what fabrics are made of — and what that means in practice — helps you make better choices.

Why fabric choice matters

Clothing production uses land, water and chemicals in growing or making the fibre; energy and chemicals in processing and dyeing; and transport at multiple stages. At end of life, some fabrics biodegrade; others persist in landfill for decades. Some release microplastic fibres every time they are washed — tiny particles that pass through water treatment and enter rivers and oceans.

The fast fashion model makes all of this worse by making cheap garments designed to be worn briefly and discarded. A well-made garment in almost any fabric, worn many times and cared for properly, is far more sustainable than a "green" garment bought, worn twice and thrown away.

Natural fibres

Natural fibres come from plants or animals. They are generally biodegradable at end of life, but growing them can use significant land, water and — depending on farming practices — pesticides.

Cotton

Conventional cotton is one of the most water-intensive crops and is often grown with heavy pesticide use. It is soft, breathable and durable when well made, and biodegrades. Organic cotton is grown without synthetic pesticides and with better soil and water management — it is a meaningfully better choice. Look for GOTS (Global Organic Textile Standard) certification as a reliable indicator.

Linen (flax)

Made from flax, linen grows with relatively little water and pesticide compared to cotton, especially in traditional growing regions. It is strong, breathable, gets softer with washing, and biodegrades. It can feel stiff initially and wrinkles easily — both are simply properties of the fibre, not defects. European-grown linen tends to have lower inputs than cotton from water-stressed regions.

Hemp

Hemp grows quickly, needs little water and very few pesticides, and builds soil health. Hemp fabric is strong and durable, softens over time, and biodegrades. It has a coarser texture than linen or cotton, which limits its use in fine garments but makes it good for durable workwear, bags and outerwear.

Wool

Wool is warm, naturally moisture-wicking, odour-resistant (meaning it needs less frequent washing), and very long-lasting when cared for. It biodegrades. The concerns are animal welfare (which varies significantly by farming standard and certification — look for Responsible Wool Standard or equivalent) and land use. Wool garments, washed cold and laid flat to dry, often last a decade or more.

Tencel / Lyocell

Tencel is a brand name for lyocell — a semi-synthetic fibre made from wood pulp (usually eucalyptus or beech) in a closed-loop process that recaptures and reuses most of the solvent used. It is soft, breathable, biodegradable and has a lower resource footprint than most cotton. It is the best-documented of the wood-pulp fibres from a production transparency standpoint. It can be delicate when wet, so follow care labels.

Synthetic fibres

Synthetics are made from fossil fuels and do not biodegrade. Their key problem, beyond their fossil-fuel origin, is microplastic shedding: every wash releases tiny fibres that pass through most water treatment systems. However, synthetics are often highly durable and have performance properties — waterproofing, stretch, warmth-to-weight ratio — that natural fibres cannot easily match.

Polyester

The most widely used synthetic fibre. Durable, quick-drying, holds colour well. Sheds microplastics when washed. Fossil-fuel derived. Recycled polyester (rPET, often made from plastic bottles) has a lower production footprint than virgin polyester, though it still sheds microfibres. Using a microplastic-catching laundry bag (such as a Guppyfriend bag) when washing any synthetic reduces shedding significantly.

Nylon

Strong, elastic, used widely in sportswear, swimwear, tights and bags. Similar issues to polyester: fossil-fuel derived, sheds microfibres, does not biodegrade. Recycled nylon (Econyl is one brand) is made from reclaimed fishing nets and other nylon waste and is a substantially better option when buying new.

Acrylic

Often used as a cheap wool alternative in knitwear. Acrylic sheds more microfibres per wash than polyester or nylon, is not readily recyclable, and has fewer of the performance benefits that make other synthetics worth considering. It is generally the least preferable synthetic option.

Semi-synthetic fibres

Semi-synthetics start with a natural material — usually wood pulp — but process it chemically into a fibre. The natural origin does not automatically make them environmentally straightforward.

Viscose / Rayon

Made from wood pulp dissolved in chemicals (typically sodium hydroxide and carbon disulphide) and extruded into fibres. The wood source matters: sustainably certified (FSC or PEFC) is better than uncertified, which may come from threatened forests. The chemical processing is resource and pollution-intensive when not properly managed. Viscose is soft and drapes well but is not particularly durable — it weakens when wet and tends to lose shape over time.

Bamboo viscose / bamboo rayon

Bamboo as a plant is impressive: it grows fast, needs no pesticides and very little water. However, most bamboo fabric is made by the same viscose process described above — the bamboo is dissolved in harsh chemicals, which largely nullifies the plant's environmental advantages. "Bamboo linen" made by mechanical processing retains more of those advantages but is much rarer and usually more expensive. If a label just says "bamboo," it is almost certainly bamboo viscose.

Modal

A type of viscose made from beech wood pulp, often processed more efficiently than standard viscose. Softer and more durable than regular viscose. Better than acrylic as a base-layer choice, though still chemically processed.

Blends and why they complicate recycling

Many garments are blends — cotton-polyester, wool-acrylic, viscose-elastane. Blends are made for practical reasons: a little stretch, better shape retention, lower cost. But blended fabrics are difficult or impossible to recycle, because the fibres cannot easily be separated. A 95% cotton, 5% elastane garment cannot be recycled as cotton.

If end-of-life recyclability matters to you, look for single-fibre garments. For most everyday use, a durable blend worn for many years is still far better than a pure-fibre fast fashion piece worn a handful of times.

The honest bottom line

There is no perfect fabric. Every fibre involves trade-offs between water use, land use, chemical processing, durability, microplastics and end-of-life options. The hierarchy, roughly, is:

• Best: what you already own, worn and cared for well.
• Very good: quality secondhand garments in any fabric — see our guide to buying secondhand.
• Good new choices: linen, hemp, organic cotton (GOTS certified), Tencel/lyocell, responsibly sourced wool.
• Acceptable with care: recycled polyester or nylon (washed in a microplastic bag), conventional cotton for items worn and washed very frequently.
• Least preferred: acrylic, conventional viscose/bamboo viscose from uncertified sources, cheap blends designed for brief use.

For clothing that already exists in your wardrobe, our clothing care guide explains how to make every fabric last as long as possible regardless of what it's made of.

Reading care labels

Care labels tell you the fibre content and how to wash, dry, iron and bleach a garment. Following them extends the life of any fabric.

• Wash temperature: lower temperatures preserve fabric structure and colour, and use less energy. Many garments labelled 40°C wash perfectly well at 30°C.
• Do not tumble dry: heat damages natural fibres and degrades elastic. Air-dry whenever possible.
• Hand wash / delicate: usually means the fabric weakens under agitation — a mesh laundry bag and a gentle machine cycle often works just as well as hand washing.
• Dry flat: applies especially to wool and loosely knit fabrics that distort under their own weight when hung wet.
• Fibre content: listed as a percentage — useful for knowing what you're dealing with and whether it can be recycled at end of life.

Fabric buying checklist

• Do I already own something that does this job? Use that first.
• Is a quality secondhand version available? Check before buying new.
• For natural fibres: is it certified organic or from a known sustainable source?
• For synthetics: is recycled polyester or nylon available? Do I have a microplastic wash bag?
• Is it a blend that will be hard to recycle? Is that a trade-off I'm willing to make for durability?
• Is the construction quality good — seams flat, stitching even, fabric weight appropriate? A well-made garment lasts regardless of fabric.
• Does the care label match how I'll actually wash it? A dry-clean-only garment you'll put in the machine won't last.