When shopping for leggings, you’ll often see fabric labels filled with words like polyester, nylon, elastane and recycled fibres. But what do these actually mean — and more importantly, do sustainable fabrics really last longer, or is longevity about something else entirely?

Let’s break it down.

The fabrics you’ll see most in leggings

Most performance leggings on the market — including those from brands like Sweaty Betty — are made from blended fabrics, not a single fibre. That’s because no one material can do everything well on its own.

Polyester (often recycled)

Polyester is one of the most common fibres in activewear.

Why brands use it

• Lightweight and quick-drying

• Excellent at moisture-wicking

• Holds its shape well

• Durable and affordable

Recycled polyester (often made from plastic bottles) reduces reliance on virgin plastic and lowers environmental impact — but it behaves almost identically to standard polyester in wear.

Longevity note:
Polyester is very durable, but it can hold odour over time if not cared for properly.

Nylon (also called polyamide)

Nylon is often considered the premium activewear fibre.

Why brands use it

• Softer and smoother against the skin

• Strong and abrasion-resistant

• Breathable with a luxurious feel

• Excellent colour retention

Longevity note:
Nylon tends to age beautifully — it resists pilling and thinning better than many polyesters when blended well.

Elastane (also known as spandex or Lycra)

Elastane is the stretch hero.

Why brands use it

• Provides flexibility and comfort

• Allows leggings to move with your body

• Helps garments snap back into shape

Elastane is never used alone — it’s always blended with polyester or nylon.

Longevity note:
Too much elastane can reduce lifespan; too little can lead to bagging and sagging. Balance matters.

Why fabric blends matter more than “sustainable” labels

Here’s the honest truth:
Sustainable fabrics don’t automatically mean longer-lasting clothing.

Longevity comes from:

• Smart fabric blends

• Quality yarns

• Construction and stitching

• How the garment is worn and cared for

A well-made nylon–elastane legging can outlast a poorly constructed recycled polyester one by years.

The role of pound-per-wear (and why it matters)

Rather than focusing only on price or sustainability claims, it’s worth thinking in terms of pound per wear.

For example:

• £80 leggings worn twice a week for 3 years = pennies per wear

• £35 leggings replaced every 6 months = far higher cost (financially and environmentally)

Longevity is sustainability in action.

Buying fewer, better-quality pieces that last longer:

• Reduces waste

• Lowers demand for fast production

• Saves money long term

So… are sustainable fabrics still important?

Yes — but in context.

Sustainable fibres help by:

• Reducing virgin plastic use

• Lowering water and energy consumption

• Supporting better manufacturing practices

But they are most powerful when paired with durability.

The most sustainable legging is the one you:

• Wear regularly

• Wash carefully

• Keep for years

The takeaway

Sustainability in activewear isn’t just about what a fabric is made from — it’s about how long it stays in your life.

The best leggings:

• Use thoughtful blends of nylon or polyester with elastane

• Balance stretch, strength and comfort

• Are designed to move, wash well, and last

Because true sustainability isn’t trend-led — it’s longevity-led.