Merino thermal underwear

Merino Thermal Underwear – Natural Warmth for Every Season

Merino wool is one of the most valued natural fabrics in the mountains. Its fine fibres are soft and do not itch, stay warm even when damp and naturally neutralise odours. That is why merino wool clothing can be worn for several days on multi-day hikes, travel and ski touring.

In this category you will find men's and women's merino thermal underwear, T-shirts, long-sleeve tops, leggings and tank tops by Sensor (Czech Republic), Kilpi (Czech Republic) and Husky (Czech Republic).

Benefits of Merino Wool

• Warm when damp: wool retains warmth even when slightly damp from sweat.
• Odour resistant: the natural properties of wool limit bacterial growth, so the garment stays fresh for longer.
• Temperature regulation: warm in the cold and breathable under effort, so it suits not only winter but also hikes in spring, summer and autumn.
• Softness: fine merino (usually under 20 microns) is soft and does not itch, unlike regular wool.
• Natural fibre: wool is a renewable resource and is biodegradable.

Pure Merino or Blends

How to Choose

For winter, choose a heavier fabric or combine light merino with a fleece on top. For summer hikes, a light merino T-shirt is an excellent choice under your backpack. See also all models in our thermal underwear category, as well as men's thermal underwear.

Why Choose Extreme Sport

We have been equipping hikers and skiers for over 22 years and are the official importer of Kilpi and Husky for Bulgaria. Try the merino clothing on at our store at 42 Dondukov Blvd in Sofia, or order online with free delivery to an office or parcel locker over 50 EUR and 30 days for returns.

Frequently Asked Questions

Does merino wool itch?
The fine merino used for base layers has very thin fibres and does not itch like regular wool. Most people wear it directly against the skin without any problem.

How do I wash merino thermal underwear?
On a wool cycle up to 30 °C with a wool detergent, without fabric softener or bleach. Dry flat, away from radiators. Merino does not need frequent washing; sometimes airing it out is enough.

Is merino suitable for summer?
Yes. Light merino T-shirts breathe well, regulate temperature and do not hold odours on long hikes in warm weather.

Why is merino thermal underwear more expensive?
Merino wool is a natural fibre with more complex processing. The garments are durable and can be worn longer between washes, which makes them good value in the long run.