G'day. I've spent a fair chunk of my life around sheep, so I'll admit I'm not exactly neutral here. But I'm also not going to stand here and tell you wool is the answer to every problem in your wardrobe, because it isn't. Cotton and polyester exist for good reasons. What I can offer, having grown one of these fibres and worn all three for most of my adult life, is an honest comparison — not a marketing table dressed up as one.
Here's the short version before we get into it: Merino is grown, cotton is grown too but processed very differently, and polyester is made from oil. That one distinction explains almost everything else about how they perform.
Temperature regulation
Merino fibre is crimped and hollow, which means it traps small pockets of air and works with your body rather than against it — it insulates when you're cold and breathes when you're warm. That's not a copywriter's line, it's why sheep wear it in the desert and in the snow. Cotton is fine in heat but goes cold and clammy the moment it's damp, which is most of the day if you're doing anything active. Polyester traps heat and doesn't breathe well at all, which is why it's usually paired with mesh panels and "moisture-wicking" treatments — workarounds for a fibre that doesn't do the job on its own.
Odour
This is the one people are most surprised by. Wool's surface structure resists the bacteria that actually cause body odour, rather than just absorbing sweat and holding onto it the way cotton does, or trapping it against synthetic fibres the way polyester does — which is why a gym shirt can smell rank after one wear no matter how many times you've washed it. I wore two Bruce shirts and a black Cassius tee for fourteen days across Italy and Ireland this July — trains, a wedding at Kilkea Castle, no laundry — and never once washed any of them. I wrote the whole story up here if you want the detail. I wouldn't attempt that in cotton or polyester, and I mean that plainly, not as a sales line.
Weight, packing, and wrinkles
Merino is fine, light, and drapes rather than creases — you can roll it into a ball at the bottom of a bag and it mostly forgets about it. Cotton wrinkles hard and takes up real room once you're packing more than a couple of shirts. Polyester packs small and springs back from creases well, which is a genuine advantage — it's one of the few places synthetic fibre has a real edge over wool.
Durability
Good merino, looked after properly, lasts for years — the fibre is strong and elastic, so it resists tearing and bounces back from stretching. It's not as abrasion-resistant as heavyweight polyester, though, which is genuinely the better choice for things like technical outdoor shells or hard-use workwear. Cotton sits in the middle: durable enough, but it weakens with repeated washing in a way wool doesn't, because wool needs so much less washing to begin with.
Care
This is where the maths tips heavily toward wool, and it's really the whole point of owning it. A cotton shirt gets washed after every wear or two. Merino, worn properly, wants airing between wears and a wash only every week or two of regular use — because the fibre resists odour instead of trapping it. Fewer washes means less wear on the garment and less time spent doing laundry, which is a genuine, if unglamorous, reason to own it.
Price, honestly
Merino costs more than a basic cotton tee or a polyester golf shirt, and I won't pretend otherwise. Fine wool is a slower, more limited resource than cotton or petroleum — it comes off a sheep's back once a year, and superfine grades like the ones we use are a smaller slice again. What you're paying for is fewer replacements, fewer washes, and a shirt that does its job in more conditions rather than needing a different garment for each one.
Where cotton and polyester still win
Fair's fair. If you need a five-dollar tee to paint a fence in, cotton is the right call — you won't mourn it. If you need something that shrugs off serious abrasion or needs to dry in ten minutes flat for a technical hike, purpose-built polyester or nylon gear does that better than wool does. I'd never tell you merino is the only fibre worth owning. I'd tell you it's the one worth owning for the things you wear most — travel, work, the shirt you reach for on a day you don't know what the day holds.
The bottom line
Cotton is grown and comfortable but high-maintenance. Polyester is technical and cheap but runs hot and holds odour. Merino sits in between on price and does more of the actual job on its own — temperature, odour, packing — without needing a wash after every outing. If you want to try it for yourself, the full range is a good place to start, or the Starter Set if you'd rather find out which one earns its keep first.
— Jock Merriman, Founder · 5th generation
