What are the best alternatives for layers

Practical test of baselayer: merino or synthetic fiber?

For several years now, merino wool has been mixing up the functional underwear front. Lingerie, which emits a distinctive odor after being worn once, was not particularly appealing to many. The wool, with its odorless character, came in handy. Even after sweating through it several times, you can still venture out with people wearing a merino wool shirt. The perfect companion for longer tours.

The initial hype in terms of merino is just leveling out. As is often the case when something new comes onto the market. Because there is no advantage without disadvantages, even if the manufacturers' marketing strategists sometimes want us to believe otherwise. Wool is not particularly strong mechanically, especially when it is thin. Anyone who has already worn a woolen item will know the small holes that often showed up in the contaminated areas after just a few washes.

In addition, wool is a moisture buffer, but it is a buffer. Wool can absorb up to 33 percent of its own weight in moisture. As long as you have a good wearing comfort. But if the buffer is full, the sweat runs down. And you have to get the moisture out of the fabric first. The drying process of merino takes many times longer than that of synthetic fiber functional shirts.

At the moment, many manufacturers mix wool fibers with synthetic materials. And from both factions: the classic wool manufacturers and the die-hard synthetic processors. Many merino manufacturers now often add five to ten percent synthetic to their products for reasons of fit and stability. Companies like Polartec, who have relied on pure synthetic fibers for years, are offering the so-called Power Wool, a mixture of merino wool and synthetic fibers, for the 2015/16 season.

And Odlo, something of a synonym for synthetic fiber underwear, relies on mixed fabrics. The idea with such material combinations is always the same: You try to combine the advantages of both materials and eliminate the disadvantages at the same time.

In our case, the combination of materials is chosen very differently. Because there are basically two ways to mix the materials:

1. They are really mixed, next to a wool fiber there is another synthetic fiber and then another wool fiber, etc.

2. You create a two-surface knitted fabric with one material on the inside and the other on the outside.

And here we have two fundamentally different approaches in the present overview. The Polartec Power Wool mentioned above relies on wool on the skin and polyester (PE) on the outside. The wool should transport moisture (sweat) away from the skin and pass it on to the outside. There it is distributed over a large surface and evaporates.

The Löffler company has been offering the opposite, so to speak, for years: Transtex Wool. The construction of this material has been chosen so that there is polypropylene (PP) on the skin and the wool on the outside. The approach here is that the wool draws moisture out of the PP from the outside, as PP virtually does not absorb any moisture.

One of the primary questions in our practical test was whether both versions of the two-tier solution work. Because it is often the case that a physical process works in one direction, but not in the other. We were therefore very curious about the 1: 1 comparison of Polartec Power Wool with Löffler Transtex Wool. But also on the direct comparison of these approaches against the other "systems". Against synthetic, of course.

The test field looked like that we tested an (almost) pure merino shirt (Iceberaker), three shirts made of mixed fabrics (Ternua with Polartec Power Wool, Löffler Transtex warm and Odlo with the material Technical Wool light) and a pure one Arc'teryx synthetic shirt made of 87 percent polyester and 13 percent polypropylene.

The test setup was very simple: 13 testers, five shirts, five days. During the big ALPIN ski test, the testers wear a different piece of functional underwear every day. In the evening it is rated. How synthetics compares to wool can be worked out by people who are concerned with the topic and have already worn different pieces. The comparison of the wool-synthetic blends with one another was therefore particularly interesting.

Löffler was able to convince with the Transtex Wool. After a day of skiing, the testers were really enthusiastic about the shirt. It's not a fashion highlight, but it works perfectly. The wearing comfort is very good, but above all the way the material "handles" sweat is perfect. The system works well even with sweat-intensive activities. The skin quickly feels dry again, but the "outside" of the shirt is still damp.

Pure merino wool has its weaknesses when it comes to intense sweating. It is very comfortable to wear and if you work up a sweat, everything is still OK. But when you sweat for a long time, merino has its problems. Because when the wool buffer is full, merino no longer warms and the wearer gets cold.

The Ternua Uigur made from Polartec Power Wool worked well too. Not quite as good in a direct comparison with Transtex, however. The wool layer on the skin is good for wearing comfort, but not quite as good for sweating. If you sweat more, your skin feels damp. The testers liked the functional shirt by Odlo the least. But that was also due to the fit, which unfortunately wasn't quite as mature (folds).

"Plastic" shirts

And what about synthetics? The "plastic" shirts are also very convincing. The material is very good, especially if you sweat a lot or exert yourself over a longer period of time (ski tour, mountain tour ...). In addition, it dries quickly because it hardly absorbs any moisture. It is less warm and therefore comfortable to wear, especially at higher temperatures. Synthetics are therefore particularly suitable when you don't have the opportunity to change your clothes after sweating.

A very typical use is as follows: A synthetic shirt (or Transtex) is perfect for the (ski) tour as the first layer for the ascent. If you hardly sweat, you can alternatively wear mixed fabrics or merino. Before the descent (or the descent) you swap your sweaty synthetic (or mixed fabric) shirt for a cozy, warm merino piece.

And what about the odor development of synthetic laundry? We also tested them: After a day on the body, we were still able to venture out among people with the Arc'teryx Phase AR and were not avoided at après-ski. However, if you want to wear a pure plastic shirt for three days without washing it in between, it slowly becomes uncomfortable. However, it is nowhere near as distinctive as it was a few years ago. Just like with merino, there are also people who simply cannot have synthetic materials on their skin. There are now alternatives for them.


  • Wool is great in winter and for people who sweat little.

  • Wool is good for stop

  • Wool is unsuitable for summer (too warm, drying times too long).

  • Synthetics and mixed fabrics are good in summer and for those who sweat a lot.

Text by Olaf Perwitzschky


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