Activewear Fabric Tier List: Every Fibre Ranked

The board

The rules are simple. Fabrics are judged on what the fibre physically does against sweating skin, not on what the ad said. If it came out of the ground as crude oil, it does not leave the bottom two rows.

S

Merino wool, 17.5 micronAbsorbs up to 30% of its weight and evaporates it. Finer than human hair.

Organic cottonGOTS certified. The fibre without the pesticide bath.

Tencel lyocellEucalyptus fibre, closed loop process. In our boxers and Merino Air knit.

A

LinenCools like nothing else. Creases like nothing else.

HempStronger than cotton and practically farms itself.

AlpacaFine, warm, low lanolin. Ask the sock brands.

B

SilkBeautiful until you sweat in it.

CashmereSofter than your willpower. Pills by week three.

C

Regular wool, 30+ micronThe itchy jumper that put you off wool for life.

Conventional cottonThe fibre is fine. The farming is not.

D

Bamboo viscoseSold as a plant. Made in a chemical bath.

ElastaneThe 6% that ruins the other 94%.

F

PolyesterMelted crude oil with a marketing budget.

Recycled polyesterSheds around 55% more than virgin. Somehow worse.

NylonSame refinery, different name.

AcrylicShed the most fibres of any fabric tested.

As sold bylululemonNIKEvuoriGYMSHARKand almost everyone else

Shedding figures: Changing Markets Foundation, 2025, and Napper and Thompson, 2016. Fibre moisture regain values from standard textile references.

The F tier writes itself

Polyester, nylon and acrylic are the same story told three ways: crude oil, refined, melted, drawn into thread, sold at about two dollars a metre. A single six kilogram wash releases over 700,000 microfibres, and those particles are turning up in human blood, in lungs, in testicles. You don't just wear plastic. You absorb it.

And recycled polyester stays in F on merit. Lab testing found it sheds around 55% more than virgin. The green story sheds more plastic than the cheap one.

C tier is why you think you hate wool

Prickle is mechanical. It comes from fibres coarser than about 30 microns poking at the skin. The jumper that ruined wool for you was cut from exactly that. Our liner is 17.5 micron, finer than human hair, nowhere near the prickle threshold, and rarer than cashmere at that grade.

Wool was never the problem. Coarse wool was. Blame the jumper, not the sheep.

S tier is just what we make

This is not a coincidence, it is the sourcing brief. 17.5 micron RWS certified New Zealand merino that absorbs moisture into the fibre core and evaporates it. GOTS certified organic cotton for the shell. Tencel in the boxers and blended into the Merino Air knit that dumps heat through an open 150gsm mesh.

The whole top row of the board, cut into shorts, tees, vests and boxers. Nothing from the bottom two rows, anywhere, ever.

Shop The S Tier

Nero Active Shorts

We went to the literal opposite end of the earth to kill off plastic sportswear forever. Nero is forged from 100% RWS-Certified New Zealand Merino Wool and GOTS-Certified Organic Cotton.

Active Icebox Thermoregulation: Naturally dumps excess body heat instead of turning your groin into a sauna.

Zero Petrochemicals: No plastic filaments shedding into your bloodstream.

No Bold Logos: Clean, athletic tailoring that looks like pure luxury, whether you're deadlifting 500 lbs or stepping off a plane.

Shop Nero Shorts

Test them out for 99 days

We're so confident you'll love Nero that we offer a 99-Day Money-Back Guarantee. No questions asked. Try them risk-free and feel the difference immediately. Say goodbye to sweaty plastic shorts forever.

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