A mountain guide from the Zillertal tests four summer shirts on demanding tours. Only one passes the test.
A mountain guide from the Zillertal experiences it on his tours every year anew: The group sweats on the ascent, shirts stick to the back – and at the summit, sweat becomes a cold trap.
"In summer, the shirt is more crucial than the jacket. If you sweat and wear the wrong fabric, you cool down at the summit so quickly that you don't have time to enjoy the panorama."
The problem with summer shirts while hiking
Almost every outdoor brand advertises their shirts as "quick-drying" and "breathable". But anyone who has reached the summit after a steep ascent and immediately felt cold knows: these promises often don't deliver.
"Polyester dries quickly – that's true. But it harbors bacteria and starts to smell after half an hour. Cotton soaks up sweat like a sponge and stays wet for hours. Both are problems on long tours."
Why the classic sports shirt reaches its limits
Polyester and synthetics work for short runs or at the gym. But during a 6-hour mountain tour under the summer sun, the demands change fundamentally.
The body sweats heavily on the ascent and cools rapidly once you stop. A shirt that stays wet becomes a cold trap. A shirt that smells makes the hut unpleasant.
"I always tell my guests: Invest in the shirt directly on your skin. Everything else you can simply take off. The base layer shirt determines how comfortable you feel all day long."
Our test criteria
| Category | What we tested |
|---|---|
| Moisture regulation | Does the shirt cool during the ascent and stay dry during breaks? |
| Odor neutrality | Does it remain odor-free even after a strenuous day? |
| Wearing comfort | Does it fit comfortably on the skin without scratching or rubbing? |
| Cooling effect | Does it actively cool in heat or trap warmth? |
| Multi-day suitability | Can you wear it for several days without washing? |
| Durability | Does it withstand backpack friction and frequent washing? |
The big summer shirt test
Four hikers from his group wore one shirt each over six weeks on various tours. Only one convinced across all categories.
- Material: 100% Cotton
- Price: approx. €25
- Dries: Very slowly
- Odor: Moderate
- Multi-day suitable: No
Comfortable on the skin, affordable – but on the first mountain tour the familiar problem: The shirt soaked up sweat like a sponge. At the summit, it clung wet to the back. The wind cut through the damp fabric.
- Material: 100% Polyester
- Price: approx. €45
- Dries: Quickly
- Odor: Strong after 2h
- Multi-day suitable: No
Dries quickly, no cooling effect at the summit – but after two hours of intense climbing, the classic synthetic problem: pungent sweat odor. Bacteria settle in the synthetic fibers.
- Material: 100% Merino Wool
- Price: approx. €90
- Dries: Moderate
- Odor: Very good
- Multi-day suitable: Yes
Odor-free, pleasant, multi-day suitable – pure merino does many things right. But at 30 degrees and 800 meters of elevation gain, the shirt remained noticeably damper than desired.
- Material: Merino + Coolmax Technology
- Price: approx. €40
- Dries: Very quickly
- Odor: Nearly neutral
- Multi-day suitable: Yes
- Mulesing-free: Yes
That was the surprise of the test. The Alpin Loacker Merino Coolmax shirt combines the best of both worlds: the natural properties of merino wool with the fast moisture-wicking of Coolmax technology.
- ✓Merino + Coolmax – Fast-drying AND odor-neutral. No more compromises.
- ✓Active cooling effect – At the summit, the shirt dries in minutes instead of hours.
- ✓No odor after days – Still fresh after 3 days in a mountain hut.
- ✓Soft on the skin – No scratching, no rubbing, even with a heavy backpack.
- ✓Temperature regulation – Cools during ascent, warms during breaks.
- ✓Mulesing-free & sustainable – For those who care about their conscience on the mountain too.
What the test hikers say
"I was skeptical whether merino really cools. After the first climb I was convinced. The shirt dries so quickly that I didn't even need to reach for my jacket at the summit."
"3 days at a mountain hut, 1 shirt. My hut mates noticed nothing. That was never possible with any other shirt before."
"I always had the problem that synthetic shirts start to smell after a short time. With the Coolmax Merino that's completely gone. Finally."
The mountain guide's conclusion
"I now recommend the Alpin Loacker Merino Coolmax shirt to all my guests. It's the only shirt I know that can really do everything in summer: cool, dry, stay odor-free."
Discover Merino Coolmax now
Test winner · Merino + Coolmax · Mulesing-free · Free shipping · 30-day returns
Go to shop →All test statements are based on the personal experiences of the mountain guide and his test hikers. Individual results may vary. The tested comparison products were kept anonymous. This is a paid advertisement from Alpin Loacker.