Not if the fibre is fine enough. The prickle people remember from wool jumpers comes from coarse fibres, roughly thicker than 30 microns, pressing against the skin. Superfine Merino is much finer than that, so it bends against the skin instead of prodding it. Itch is a fibre-diameter problem, not a wool problem.
By Jock Merriman, fifth-generation Australian Merino woolgrower and founder of Sir W. Merino. My family has grown Merino since 1880, and my father George still runs the Merryville stud in Boorowa, New South Wales.
Why am I qualified to answer this?
Because I grew up wearing wool and watching it being sorted, and because since I moved to Austin in 2018 it is the question I get asked most. Almost everyone has a scratchy-jumper memory. They are right to remember it. They are just blaming the wrong thing.
Why does some wool itch?
It is mechanical, not an allergy. Fibres thicker than about 30 to 32 microns do not bend easily when they touch skin, and your nerve endings register a small prod. Lots of those prods read as itch. A micron is one-millionth of a metre, and the difference between a prickly fibre and a comfortable one is a handful of them.
How fine is Merino?
It depends on the grade. Under the industry definition, superfine Merino is 17.5 microns or finer. Our yarn sits at roughly 17.5 to 19. Research on young children with eczema found superfine Merino under 18.5 microns was well tolerated. Merino is a breed, but micron is the grade, so ask for the number.
Am I allergic to wool?
Very probably not. A review of more than a century of research concluded that wool itself is not an allergen. What people call a wool allergy is nearly always prickle from a coarse fibre.
Who should still be careful?
This is where I will not oversell. If you have very sensitive or eczema-prone skin, try a garment on a small area before committing, and expect the first wear to tell you more than any brochure. Fit matters too: a snug neckline or seam can irritate on its own. Different people also react differently to the same fabric. Fine fibre removes the main cause of itch. It does not guarantee that every skin will love every shirt.
What should I look for in a Merino shirt?
Look for a stated micron, a soft knit and flat seams. If you want to start where the skin is most sensitive, The George is a polo with a collar that sits at the neck, which is the test most people care about.
— Jock Merriman, Founder · 5th generation
