The Best Underwear Fabrics Compared: Cotton, Modal, Microfibre, Silk and Merino
Which underwear fabric is best for comfort, breathability and everyday wear? A textile engineer compares cotton, modal, microfibre, silk and merino.
The short answer
For most people, the best everyday underwear fabric is cotton or a cotton-modal blend with a cotton gusset. Modal is softer and smoother; microfibre is best under fitted clothes and for sport; silk is a luxury choice; merino is excellent for travel, hiking and cold weather. Whatever the main fabric, a breathable cotton gusset is the detail that matters most for comfort and health.
As a textile engineer with more than 14 years of fabric development behind me, and as the founder of a lingerie brand, this is how I compare underwear fabrics.
Underwear fabrics compared
| Fabric | Breathability | Softness | Moisture handling | Durability | Best for |
|---|---|---|---|---|---|
| Cotton (with elastane) | High | Soft, matte | Absorbs well, dries slowly | Good | Everyday wear, sensitive skin |
| Modal (with elastane) | High | Very soft, silky | Absorbs well, dries faster than cotton | Good | Everyday comfort, warm weather |
| Bamboo viscose | High | Very soft | Absorbs well | Fair | Soft everyday wear; wash gently |
| Microfibre (nylon/polyester + elastane) | Medium | Smooth, sleek | Wicks sweat, dries fast | Very good | Under fitted clothes, sport |
| Silk | High | Luxuriously smooth | Good | Delicate | Special occasions, sleep |
| Merino wool | High | Soft (fine grades) | Excellent, resists odour | Good | Travel, hiking, cold weather |
What to look for in any pair
- A cotton gusset. It is the lining in the crotch. Cotton breathes and absorbs, even when the rest of the garment is microfibre or lace.
- Elastane around 5–10%. Enough for shape recovery; more makes the fabric feel tight and warm.
- Soft, covered waistbands. Exposed elastic rubs and wears out first.
- Flat or bonded seams under fitted clothing, to avoid lines and chafing.
- OEKO-TEX Standard 100 for anything worn against the skin all day.
Matching fabric to the day
- Hot, humid days: modal or cotton.
- Gym and running: microfibre or merino, which wick sweat and dry quickly.
- Under fitted dresses and work trousers: seamless microfibre.
- Travel: merino, which can be worn more than once between washes and resists odour.
- Sensitive skin: plain cotton with a cotton gusset and minimal dyes or finishes.
CALIDA Women's Richesse Wool-Silk Underwear
- 70% new wool, 30% silk
- Machine washable
Luxury choice for cooler months
Check price on Amazon AU Price & availability shown on Amazon.com.auOur own TOZAHIDA lingerie is designed around fabric comfort first. You can browse the collection here.
Frequently asked questions
What is the healthiest fabric for underwear?
Breathable fabrics with a cotton gusset are the safest everyday choice, especially for anyone prone to irritation.
Is modal underwear better than cotton?
Modal is softer and smoother and dries a little faster. Cotton is slightly more breathable and very durable. Both are good choices. Read more in our modal fabric guide.
Is microfibre underwear bad?
No. It breathes less than cotton, but it wicks sweat and dries quickly, which makes it great for sport and under fitted clothes. Choose one with a cotton gusset.
How often should underwear be replaced?
Replace pairs when the elastic loosens, the fabric thins or holes appear. With regular rotation, that is often around a year. See our guide on how to wash bras and lingerie to make them last longer.