Causes and Solutions for "Itchy" Knitwear

The cause of that prickly sensation is the "stiffness" and "thickness" of the fibers.

When knitwear feels itchy, the most common causes areThe thickness and stiffness of the fibers usedis located there.
Animal fibers, such as wool, have a scaly surface structure known as “scales,” and when this uneven surface comes into contact with the skin, it can easily cause irritation. The thicker the fiber, the stronger this irritation tends to be, and people with sensitive skin often perceive it as a prickly sensation.

Guideline

• The fiber diameter (in microns) is20 μm or more→ Prone to itching

• Extra-Fine Merino (19 μm or less)→ Smooth and gentle on the skin

"Yarn twist" and "knitting technique" also play a role

The feel against the skin also varies depending on the tightness of the yarn twist and the density of the knit fabric.
・High-twist yarnIt tends to become stiff and rough
・Loose-knit (coarse knit)It has a large surface area that comes into contact with the skin, so it’s easy to feel a prickly sensation.
・High-gauge (fine knit)It has a smooth surface and is less likely to feel prickly.

In other words, even with the same material,How comfortable a garment is depends on how it's knitted.That's right.

Static electricity and dry skin also contribute to that “prickling” sensation

Due to the dry air in winter and layering clothes made of synthetic fibers,Static electricity is generatedIt will be easier.
This can cause a slight irritation to the skin, which may feel like a "prickling" sensation.
In addition, when your skin is dry, its barrier function weakens, making it more likely for even minor irritations to cause pain.

Since static electricity is more easily discharged by moisture, materials with high moisture-absorbing properties are less likely to generate static electricity.

Examples: Acrylic, polyester → become negatively charged; wool, nylon → become positively charged; cotton, linen → are less likely to become charged

Static electricity is less likely to occur when negative charges are paired with negative charges or positive charges are paired with positive charges.

Solutions for Reducing Itching

Wear an extra layer of underwear

To avoid direct contact with your skin,Cotton and silk undergarmentsSimply layering them can make a big difference in comfort.
We recommend wearing a thin undershirt underneath, especially when wearing a "100% wool" knit.

Care with fabric softener or conditioner

Using fabric softener when doing laundry coats the surface of the fibers, which helps reduce friction.
If it's just a slight tingling sensation,Laundry Detergent for Delicate Clothes + Fabric SoftenerThis can sometimes lead to significant improvements.

Reevaluating Material Selection

We recommend the following materials for people with sensitive skin.

• Extra-Fine Merino Wool(Thin and soft)

• Cashmere(High heat retention and extremely smooth)

• Alpaca(Hollow structure that minimizes itching)

• Cotton-Silk Blend(For a gentle feel on the skin)

Which is more itchy: synthetic fibers or animal-based fibers?

Conclusion: It is said that the "thickness" of the fiber is the main factor, rather than whether it is a synthetic or animal-based fiber.

"Scale Structure" on the Fiber Surface

Animal fibers (such as wool, alpaca, and mohair) have structures called “scales” on their surfaceScaly, uneven surfaceThere is.
When these scales come into contact with the skin, they cause friction, which people with sensitive skin perceive as a “prickly” sensation.

Fabrics with particularly thick fibers and pronounced scale irregularities (e.g., standard wool) can be more irritating.
Animal-based fibersBut,Cashmere(thin),Merino Wool(Relatively fine) yarns are said to cause less itchiness and feel very smooth against the skin.

Synthetic fibers have a “smooth” surface.

Polyester, nylon, acrylic, and otherSynthetic fibers have a uniform, man-made structureIt is made of [material], and its surface is smooth.
As a result, it causes less physical irritation (such as a prickly sensation) than wool and feels relatively smooth against the skin.

However, static electricity tends to build up, andDiscomfort caused by dryness or a tingling sensationI sometimes feel that.
In other words, while it’s less likely to cause a “prickly” sensation, it’s more likely to cause a “tingling” sensation or a “sticky” feeling.

Animal-based fibers (such as wool): The tips of the fibers can irritate the skin, causing a prickly sensation. However, high-quality materials with fine fibers, such as cashmere and baby alpaca, are less likely to cause this prickly sensation.

Synthetic fibers (acrylic, polyester, etc.): Generally, many of these fabrics have fine fibers and feel smooth against the skin, but depending on the material, they may have a distinctive texture or cause a prickly sensation due to static electricity. They may also be blended with wool.

The Difference Between Elasticity and Hardness

Animal-based fibers areHigh elasticity (resilience)As a result, you feel a sensation as if the product is being pushed back against your skin.
On the other hand, synthetic fibers tend to have a uniform softness and are less likely to cause irritation.

Tips for Choosing "Non-Itchy Knitwear"

1. Check the "Type of Wool" and "Micron Rating" on the label

Check the thickness of the fibers

2. Choose Materials

• Cashmere(Animal-based fibers): These fibers are very fine and supple, and are said to feel pleasant against the skin.

• Silk(Animal-based fibers): This material feels soft against the skin and is supple.

• Cotton(Plant-based fibers): They are soft and gentle on the skin, but may lack the fluffy texture typical of knitwear.

• Merino Wool(Animal-based fiber): This variety has finer fibers than regular wool and is less likely to feel itchy.

• Nylon, Polyester(Synthetic fibers): While some types are less likely to cause skin irritation from friction, they also tend to trap moisture and generate static electricity more easily due to their low moisture-absorbing properties.

3. Try gently holding it against your neck or wrist in the store

4. Also use labels such as “smooth finish” and “shrink-resistant” as a guide.

To choose a knit that doesn’t itch, it’s important to understand the properties of the fabric and test it against your skin. By considering all four points we’ve discussed, you can find a piece that’s comfortable for you.

Summary

The itchiness caused by knitwear is a phenomenon resulting from a combination of “material, construction, environment, and skin condition.”
Even people who used to think, “I have sensitive skin, so I can’t wear knitwear,”With just a little thought put into the materials and how you wear it, you can enjoy it comfortably.It will look like this.
To ensure your favorite piece lasts for years to come, pay close attention to the materials you choose and how you care for it.

If you'd like to learn more,

The content of this article has been independently edited and organized using research and AI. For those who wish to learn more about the properties of textiles and clothing care in greater depth, we recommend consulting a specialized institution such asJapan Clothing Management Association (General Incorporated Association)Well,
Text widely used in the industryBasic Knowledge of Textile Products (Newly Revised Edition), 3-Volume SetThis may be helpful.
This resource provides a systematic overview of fiber structure, material properties, and handling methods.