Polyester and nylon are both plastic. Full stop. They're both made from petroleum, both shed microplastics, both trap heat against your skin, and both will sit in a landfill for centuries. But if you're comparing them — maybe because a garment contains one or the other and you want to know which is the lesser evil — here's the honest breakdown.
The Quick Comparison
| Property | Polyester | Nylon |
|---|---|---|
| Chemical name | Polyethylene terephthalate (PET) | Polyamide (PA) |
| Source | Petroleum | Petroleum |
| Moisture absorption | 0.4% | 4% |
| Softness | Slightly rough | Softer, smoother |
| Durability | High (resists UV, chemicals) | Very high (best abrasion resistance) |
| Stretch | Low inherent stretch | More naturally stretchy |
| Drying speed | Faster | Slower |
| Wrinkling | Very wrinkle-resistant | Slightly more prone |
| UV resistance | Better | Degrades in sunlight over time |
| Odour | Terrible | Also terrible |
| Microplastics | Yes | Yes |
| Biodegradable | No (200+ years) | No (200+ years) |
| Price | Cheaper | More expensive |
Comfort & Feel
Winner: Nylon (marginally).
Nylon is inherently softer and smoother than polyester. It has a more fluid drape and sits against skin with less friction. This is why nylon dominates in underwear, stockings, and sports bras — applications where fabric-to-skin contact matters.
Polyester feels slightly rougher and more "plastic" against bare skin. It's perfectly fine for outer layers but noticeably less pleasant as a base layer or for intimate garments.
That said, both are dramatically less comfortable than cotton, silk, or Tencel. Nylon winning the comfort comparison between two plastics is like winning the "least uncomfortable plastic chair" award.
Moisture & Breathability
Winner: Nylon (slightly).
Nylon absorbs about 4% of its weight in moisture. Polyester absorbs 0.4%. In absolute terms, this means nylon pulls some sweat into the fibre rather than leaving it all on the surface — which makes it marginally less clammy against skin.
But let's be honest: both are terrible at this. Cotton absorbs 27%. Merino wool absorbs 35%. The difference between 0.4% and 4% is the difference between "awful" and "slightly less awful." Neither synthetic breathes in any meaningful sense.
Durability
Winner: Nylon (for abrasion), Polyester (for UV and chemicals).
Nylon is the toughest common textile fibre. It has the highest abrasion resistance, which is why it's used in backpacks, climbing ropes, parachutes, and luggage. If you need fabric that won't wear through from friction, nylon wins.
Polyester is more resistant to UV light (sunlight doesn't degrade it as fast), chemicals, and stretching. It holds its shape better over time and doesn't yellow with age.
For everyday clothing, the durability difference is irrelevant. Your t-shirt isn't being tested for tensile strength. You'll stop wearing it long before either fabric physically fails.
Environmental Impact
Winner: Nobody. Loser: The planet.
This is where comparing polyester and nylon gets depressing, because they're both environmental disasters — just in slightly different ways.
- Production emissions: Nylon is worse. Manufacturing nylon 6,6 releases nitrous oxide — a greenhouse gas 310x more potent than CO2. Polyester production is energy-intensive but doesn't have this specific chemical problem.
- Scale of damage: Polyester is worse. It accounts for over 50% of global fibre production. Nylon is a fraction of that volume. Polyester's total environmental footprint is vastly larger simply because there's so much more of it.
- Microplastics: Both shed them. Both contribute to the estimated 35% of ocean microplastics that come from textile washing.
- End of life: Both take 200+ years to decompose. Both end up in landfill. Neither can be meaningfully recycled when blended with other fibres (which they almost always are).
When Each Makes Sense
There are genuine use cases where synthetic fabrics are hard to replace:
Use nylon when:
- Swimwear — needs to handle constant water immersion without degrading
- Tights/stockings — no natural fibre achieves the same sheerness and stretch
- Genuine technical outerwear — climbing gear, performance jackets
Use polyester when:
- Raincoats — water resistance is the primary function
- High-UV exposure gear — sun hats, sailing clothing
- Industrial workwear — where chemical resistance matters
Use neither when:
- Everyday t-shirts, shirts, dresses — cotton, linen, and silk do this better
- Underwear and bras — cotton or Tencel are dramatically better against skin
- Sleepwear — you don't need plastic touching your skin for 8 hours
- Gym wear — merino wool outperforms both for odour and comfort
- Anything where breathability matters — which is almost everything
The Real Question
"Polyester vs nylon" is the wrong comparison for most people. The real question is: "Do I need synthetic fabric at all?"
For swimwear, tights, and genuine outdoor performance gear — yes, synthetics serve a real purpose. For the other 90% of your wardrobe — the t-shirts, dresses, underwear, and casual clothes that make up your daily life — natural fibres outperform both polyester and nylon on every measure that matters to your body.
The best synthetic is the one you didn't need to buy.