Ice silk underwear feels cool because it is not silk at all: it is a very fine, smooth knit, usually modal or a modal-style blend, that lies flat against the skin, spreads body heat across its surface and pulls moisture away so it can dry fast. Cared for correctly, with a cool wash and no fabric softener, that slippery, lightweight feel lasts for a long time. This guide explains what ice silk and modal are, why they feel the way they do, how to choose a cut, and how to wash and dry them so they stay smooth.
What is ice silk underwear?
"Ice silk" is a trade name, not a fibre. It describes a family of ultra-fine knits with a cool, slick hand feel. In men's underwear the name usually points to modal, a fibre made from beechwood cellulose, or to a similarly smooth, stretchy blend. What these fabrics share is a tight, even knit with a glossy surface and very little texture, which is what gives the "second skin" sensation people describe.
Modal belongs to the rayon family. It has a smoother fibre surface than cotton, more drape and a softer hand, which is why modal and ice silk underwear glide under clothes instead of gripping them.
Within the Arjen Kroos range, the Men's Ice Silk Trunks are made from a soft modal fabric with mesh panels for airflow, while other styles in the silk underwear collection use smooth ice silk knits with a similar feel.
Why ice silk and modal feel cool
The "cool" feeling comes from three things working together, and none of them involves the fabric actually being cold.
- Smooth surface, more skin contact. A flat, fine knit touches more of your skin than a fluffy cotton one. More contact means heat moves from your skin into the fabric faster, which your nerves read as "cool".
- Fast moisture transport. Modal absorbs moisture well and releases it quickly, and a thin knit dries much faster than a thick one. Dry skin feels cooler than damp skin, especially on a warm day or after a commute.
- Low weight and drape. Ice silk underwear weighs very little and moves with you. Nothing bunches, so there is no warm, trapped layer at the thigh or waistband.
Mesh panels add to the effect. The Ice Silk Trunks combine soft modal with mesh zones at the sides, so air can pass through where you sweat most. The Mens Silk Boxers use the same idea: a smooth ice silk body, breathable mesh panels and a seamless construction that dries quickly and resists losing its shape.
Ice silk vs modal vs cotton at a glance
| Feature | Ice silk / modal | Cotton |
|---|---|---|
| Hand feel | Slick, smooth, light | Soft, matte, slightly textured |
| Drying speed | Fast | Slow when wet |
| Visibility under clothes | Very low, no lines | Can show edges under slim trousers |
| Stretch and recovery | High, holds shape | Moderate, can bag out |
| Best for | Warm weather, slim fits, everyday comfort | Cool weather, relaxed fits |
| Care | Cool wash, no softener, air dry | Tolerates warmer washes |
If you want the full fabric comparison, read Mesh vs Cotton vs Modal: Which Men's Underwear Fabric Is Best?
Which cut to choose in ice silk
Because the fabric is thin and stretchy, the cut matters more than it does with cotton. A pouch that is too shallow or a waistband that is too narrow will show up quickly. Look for:
- A contoured or 3D pouch. Every ice silk style in the Arjen Kroos range uses a shaped pouch. It keeps the front from flattening and stops the fabric from sticking. The Men's Sexy Silky Trunks pair a 3D U-pouch with a short 3 in (7.6 cm) inseam for a classic low-rise trunk.
- A wide, stay-put waistband. Thin fabric needs a waistband that grips without rolling. The Ice Silk Trunks and the Silk Breathable Boxer Briefs both use a stretchy band designed to sit flat and stay in place.
- Flat or bonded seams. Flat seams disappear under slim jeans and chinos. The Men's Modal Silky Trunks add a tag-free finish and a breathable lining inside the pouch.
- Low rise if you wear low-cut trousers. Most ice silk trunks sit low on the hip, which suits tailored and slim fits. Our low rise underwear collection gathers these styles in one place.
Prefer a print? The Silky Printed Trunks use the same smooth ice silk knit in ten patterns, from leopard to graffiti and floral.
Sizing: ice silk runs close to the body
Ice silk and modal styles are cut to fit snugly, and several of our product pages note that they run small. If you are between sizes, or you normally wear a relaxed cotton boxer brief, size up. As a reference, the Ice Silk Trunks cover these waist ranges:
- S: 66-74 cm (26-29 in)
- M: 71-78 cm (28-31 in)
- L: 76-84 cm (30-33 in)
- XL: 81-90 cm (32-35 in)
- XXL: 86-94 cm (34-37 in)
Measure your natural waist where the band will sit, not where your trousers sit. For a full walkthrough, see our men's underwear size guide.
How to wash and care for ice silk and modal underwear
Fine knits are easy to care for, but they are less forgiving of heat and harsh chemicals than cotton. Follow these steps and the smooth hand feel will last:
- Wash cool. Use a 30°C (cold or cool) cycle. Heat is what slowly dulls the surface and loosens the stretch.
- Choose a gentle or delicates cycle. A slower spin reduces friction and pilling.
- Use a mesh laundry bag. It stops waistbands catching on zips and hooks from other garments.
- Skip fabric softener. Softener coats the fibres and blocks the moisture transport that makes ice silk feel cool in the first place. A mild liquid detergent is enough.
- No bleach, no stain sticks with bleach. They weaken modal fibres and can discolour dyes.
- Air dry, out of direct sun. Lay flat or hang on a line in the shade. Thin knits dry in a couple of hours. If you must tumble dry, use the lowest heat setting and remove while slightly damp.
- Never iron. Ice silk comes out of the wash smooth. If a piece looks creased, hang it and the wrinkles drop out.
Wash new pairs before the first wear, and rotate a few pairs so no single one is washed every day. Our article on how to wash men's underwear so it lasts longer covers detergents and storage in more detail.
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Frequently asked questions
Is ice silk underwear real silk?
No. Ice silk is a marketing name for very smooth, fine knits, usually modal or a modal-style blend. It gives a silky feel with far easier care than real silk.
Does ice silk keep you cooler than cotton?
It feels cooler because it is thinner, touches more skin and dries faster. On a hot day the difference is noticeable, especially under slim trousers.
Can I tumble dry modal underwear?
Air drying is best. If you need the dryer, use the lowest heat and take the pairs out while slightly damp. High heat shortens the life of the stretch.
Why does my ice silk underwear feel less smooth after a few months?
The usual causes are fabric softener build-up, hot washes or a hot dryer. Switch to a cool wash with mild detergent and no softener, and the surface stays slick far longer.
Should I size up in ice silk?
Often, yes. These styles are cut close and several product pages state they run small. Check the waist chart on each product page and size up if you are near the top of a range.
Find your pair
Browse the complete men's silk and ice silk underwear collection, or explore all cuts in boxer briefs and trunks and our best sellers. Every order ships in discreet packaging.
