Merino Sheep
Are Merino socks itchy?
Mid to high-quality Merino wool socks will not cause itching, as these socks use a fine fiber, which is soft and pliable. However, low-quality Merino Wool or socks blended with inferior textiles can still be itchy, even if predominantly Merino.
The amazing qualities of MERINO WOOL is well known, such as:
“Wool has the unique ability that it virtually is self-cleaning”
Merino keeps you warm when it's cold and cool when it is hot
Don’t get creases due to its natural “memory”
Absorbs over 30% of its weight in water or perspiration without feeling wet, which makes them perfect for outdoor activities
Odor-resistant due to their natural anti-bacterial properties, which means you can wear them multiple times before washing
MERINO SOCKS DON'T ITCH…..so why doesn’t it itch and are all Merino socks itchiness free?
Why isn’t Merino Wool itchy?
Traditional wool fibers are large in diameter, making them stiff. It’s this stiffness that rubs against your skin and prickles it, causing you to feel itchy. Merino Wool, by contrast, has very fine threads, which allows the fibers to bend and flex, making them feel soft on your skin.
The tactile discomfort or itchiness that people experience with wool is because traditional wool has thick fibers that poke your skin as opposed to flex around it as do the finer fibers of Merino.
“The threshold force for buckling is highly dependent on fibre diameter.”
Image Source and Text: Dr. Geoff Naylor
Microns, merino measurements & the “itch factor”
What is a micron and how does it relate to wool itchiness?
A micron or micrometer (μm), is a unit of measure of length and equates to one-thousandth of a millimeter (.000039 inch). The micron is used to measure the thickness or diameter of microscopic objects or microorganisms, including the fiber thickness of wool and other clothing materials.
Any clothing that touches your skin will feel itchy if it has a fiber diameter above 28 microns, such as traditional wool. This is known as the "comfort factor" or "itch factor."
The “Itch Factor” and Merino Wool thickness
Itch factor = Anything above 28 microns (some experts say 23 microns)
“Regular” Merino Wool (Super-fine) - 17 to 18.5 microns
Extra Fine = 15 to 16.5 microns
Ultra-Fine = Below ~14.9 microns
Cashmere (for comparison) less than 19 microns
Traditional Wool = Around 30 microns at a minimum
Human Hair - about 75 microns
“The Merino wool fiber used in the clothing for this study was all of fine diameter, which has been demonstrated to be comfortable to wear”
A 2019 study published in Dermatitis, evaluated the effects of wearing Merino wool (≤ 17.5 μm) vs standard clothing with kids and adults suffering from eczema (atopic dermatitis).
The researchers concluded, that “wearing fine-diameter Merino wool garments may actually improve signs and symptoms in patients with mild to moderate atopic dermatitis.”
If children and adults with eczema can alleviate symptoms by wearing Merino wool and improve their quality of life (according to the researchers), then it’s clear why Merino is synonymous with “soft wool.”
Low-quality merino wool can still be itchy
“Prickle is solely fibre diameter dependent, and amount of prickle increases drastically with small increase in the fibre diameter”
Fiber diameter is the most important measure for Merino Wool comfort. However, low-quality Merino wool clothing can still be itchy as it only takes 2 to 3% of the total fibers to be ‘thick’ to feel prickly. A piece of clothing averaging 16 microns will still feel itchy if 2 to 3% of those fibers are above 28 microns. Also, fiber length can affect the “itch” feel, but to a much lesser extent. Shorter fibers cause more ‘prick’ as more fiber ends make contact with your skin, making shorter fibers feel coarser.
3 things that make you itchier
“superfine and ultra fine Merino wool garments with finer fibre diameters do not activate sufficient c-fibres responsible for itch transmission”
Body part - Hairy body parts are more sensitive to textiles
Age: As you age, your skin becomes less sensitive, so younger people are more likely to experience itch from clothing……one reason why Grandma makes those super itchy sweaters…it doesn’t bother her.
High humidity or hot temperatures will soften your skin, which increases sensitivity to discomfort
These three variables can make you more susceptible to itch. However, if you wear extra-fine or ultra-fine Merino wool, you will avoid the itch and enjoy all the wonderful benefits of the greatest natural textile.
Jesse is the Director of Pedal Chile and lives in Chile’s Patagonia (most of the year). Jesse has a Master of Science in Health & Human Performance and a Bachelor of Science in Kinesiology. Hobbies: MTBer, snowboarder, reader of narrative non-fiction, a taster of craft beers, and lover of Merino wool.
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Sources
Fowler, J.F., Fowler, L.M. and Lorenz, D. (2019). Effects of Merino Wool on Atopic Dermatitis Using Clinical, Quality of Life, and Physiological Outcome Measures. Dermatitis, 30(3), pp.198–206.
Holman, BWB and Malau-Aduli, AEO 2012, 'A Review of Sheep Wool Quality Traits', Annual Review & Research in Biology, vol. 2, no. 1, pp. 1-14.
Klepp, Ingun & Tobiasson, Tone & Bandlien, Charlotte. (2010). A Fresh Look at Wool.
Naylor, G. Innovations in wool textile technology Comfortable next-to-the-skin wool.
Udakhe, Jayant & Tyagi, Shishir & Shrivastava, Neeraj & Bait, Smita & Bhute, Aniket. (2012). Effect of yarn hairiness, DBD plasma and enzyme treatment on itching propensity of woollen knitwear. Colourage. LXI. 46-51.
Zallmann, M., Smith, P., Tang, M., Spelman, L., Cahill, J., Wortmann, G., Katelaris, C., Allen, K. and Su, J. (2017). Debunking the Myth of Wool Allergy: Reviewing the Evidence for Immune and Non-immune Cutaneous Reactions. Acta Dermato Venereologica, 97(8), pp.906–915.