Best Fabrics For Sensitive Skin
Most advice on this is written for people who react to everything. This is written for men who react to some things and have never worked out which.
Here is the ranking that matters, and the one number that decides most of it.
It is almost never the fibre. It is what was done to it.
Genuine fibre allergies are rare. What is common is reacting to the chemistry on top of a fibre: disperse dyes, anti-odour finishes, softeners, and the residues left by processing.
Which is why two cotton t-shirts can feel completely different against the same skin, and why the fibre on the label tells you less than the certification does.
The one number that decides it
Wool prickle is mechanical, not allergic. It correlates with the percentage of fibres coarser than about 30 micron, which is why one wool garment itches and another does not.
Source: Naylor, Stanton and Speijers, Textile Research Journal, 2014.
The four worth wearing.
Superfine merino
At 17.5 micron and below it sits under the prickle threshold entirely. It also regulates temperature and moves moisture into the fibre rather than leaving it on skin, which is the state most irritation starts from.
GOTS organic cotton
The fibre is fine. What matters is GOTS certification, which bans chlorine bleach and toxic heavy metals and restricts processing chemicals to an approved list. Uncertified cotton tells you nothing about what is on it.
Tencel lyocell
Smooth-surfaced and made in a closed loop that recovers over 99.8% of its solvent. The smooth fibre surface means less mechanical friction than a rougher natural fibre at the same weight.
Linen
Breathable and low-processing, though it creases and it is stiff until broken in. Better for everyday than for training, where the weave is too open to manage sweat.
Wool has been trialled against skin, not just marketed for it.
In a randomised crossover trial of 39 children with mild to moderate eczema, superfine merino worn against the skin for six weeks reduced severity compared with cotton. The improvement reversed when they switched back.
That result runs directly against what most people assume about wool, and it is the difference between superfine and coarse.
The three to avoid.
Traps heat, holds moisture on the surface, and gives odour bacteria a place to live. It also carries antimony from manufacture, a fraction of which migrates into sweat in lab testing.
Dense, non-porous and engineered to grip. It turns up in liners and waistbands, which is exactly where friction and moisture meet.
Above 30 micron the fibre ends are stiff enough to trigger the prickle response. This is the wool that gave wool its reputation, and it is a different material from what is in a merino liner.
Test it on the layer closest to you.
If you are going to change one thing, change the liner and the underwear. They are held against skin for longer than anything else you own, and they are almost always synthetic even when the shell is not.
Ninety-nine days to decide, and a full refund if it is not right.
Shop Organic Cotton Boxers“I Wish I’d Tried Them Sooner”
99-Day Money-Back Guarantee
Don’t absolutely love your Nero Shorts? No worries, we uphold a 99-Day Money-Back Guarantee. No questions asked.
New Zealand Merino
Our Merino Wool is sourced and produced in NZ and production is finished locally.
Fast And Free Shipping
Get free shipping and 3-4 day delivery
The short version
Superfine merino, GOTS organic cotton and Tencel are the three worth wearing against sensitive skin. Polyester, nylon and coarse wool are the three to avoid, for three completely different reasons.
And the fibre on the label matters less than the certification next to it, because most reactions are to what was applied to a fabric rather than what it was made from.
More on that in chemicals in gym clothes, and on friction specifically in polyester and skin irritation.