Activewear guide: what workout clothes are made of

Workout clothes are one of the few categories where the fibre content changes how the garment performs, not just how it feels. This guide explains what each fibre does when you sweat in it, how to read an activewear label, and what the pieces we sell are actually made of.

What activewear is made of, and why

Nearly all performance clothing is synthetic, and that is a design decision rather than a corner being cut.

• Polyester holds very little water. It moves sweat along the fibre surface and dries quickly, which is why it dominates running and gym kit.
• Nylon and polyamide are stronger and softer against the skin than polyester, so they turn up in leggings and anything that takes abrasion.
• Elastane and spandex are the stretch. Five per cent is usually enough for movement; higher percentages give compression.
• Cotton is comfortable and breathable but absorbs sweat and stays wet, which makes it better for warming up, the walk home and the sofa than for a hard session.
• Merino wool manages odour and temperature well and dries slowly. It is expensive and we do not currently stock it.

A garment being synthetic is not a fault in this category. It is the reason the garment works. The honest problem in activewear is not polyester; it is polyester sold without saying so.

What to check on the label before you buy

1. Is a full composition stated? In the EU every textile product has to state its fibre percentages before you buy, online included. If a page will not, that tells you something about the seller.
2. How much stretch fibre? Around 5% elastane means comfortable movement. 15% and above means compression, which some people like and some find restrictive.
3. Opacity. Thin light-coloured leggings go sheer when stretched. Look for a stated fabric weight, or buy dark.
4. Flat seams. Raised seams at the inner thigh and under the arm are where chafing starts.
5. Care. Wash cool, skip the fabric softener, and air-dry. Heat is what kills elastane, and a legging that has lost its recovery is finished regardless of what it cost.

The microfibre question, honestly

Washing synthetic fabric releases tiny fibres into the water. That is established. How much any individual garment sheds depends on the fabric construction, the machine and the wash cycle, and we have not measured it for anything we sell, so we are not going to publish a figure. Washing less often, on cooler and shorter cycles, and with a full drum, reduces it. A filter bag or an in-machine filter catches some of it. Anyone selling you activewear with a precise shedding percentage should be asked where the number came from.

What our own activewear stock looks like

We checked all 1,441 clothing products we sell in September 2026. We hold a full fibre composition for 920 of them and not for 521. Among the ones we can measure, 451 are at least 80% synthetic, which for performance pieces is exactly what you would expect and for a summer dress is a different conversation. The full figures are in our label truth report, including the supply lane where almost nothing is documented yet.

We are not going to tell you our activewear is good for the planet. What we can do is tell you what it is made of, and say so plainly when we do not know.

Four pieces, with what they are made of

Blush Pink Cropped Zip-Jacket & Straight-Leg Jogger Set

95% cotton, 5% spandex. A warm-up and rest-day set, not a running kit.

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Hooded Wrap-Front Sweatshirt with Thumb-Hole Cuffs

92% cotton, 8% spandex. Breathable and absorbent, so it stays wet if you sweat hard in it.

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Venaton Two-Piece Set

95% polyester, 5% spandex. Dries fast and keeps its shape; fully synthetic, and we say so.

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Moisture-Wicking Cropped Performance Pants

The maker names polyester but gives no percentages. That is a gap on our side, and it is one of the 521.

View product

Questions people ask

Is cotton activewear better than polyester?

Not for hard training. Cotton absorbs sweat and stays wet, which gets heavy and cold. Polyester and nylon move moisture away and dry fast. Cotton is pleasant for low-intensity sessions, warm-ups and afterwards.

How long should a pair of leggings last?

Elastane is what fails first, and heat is what kills it. Washing cool and air-drying extends the life of a legging far more than the purchase price does. When the fabric stops springing back, the garment is done.

Do you sell certified organic or recycled activewear?

No. We hold no certifications and we do not claim any. We tell you the fibre composition where the maker states it, and we tell you when it is missing.

Why does one of the products above have no percentages?

Because its supplier has not given them to us yet. We could have quietly left it off this page. Publishing it is the point: 521 of our 1,441 clothing pages are in the same position, and the label truth report counts every one.

Browse the rest of the range in clothing. Every page that has a composition states it.