As a person who gets cold relatively easily but spends a large part of the day outside, I was thrilled when I saw the reviews. I thought, this is it, I won't be cold again... umm, no. So, I wore it on Mount Olympus on bare skin, with a short-sleeved shirt on top, a thick Columbia fleece, softshell, and hardshell. That was during an ascent with a full backpack. My temperature was fine, I wasn't hot nor cold. I also slept with only this inside the sleeping bag at the refuge, and even there I wasn't warm (the refuge must be at 14 degrees). Of course, I am quite thin but still, it didn't come close to the warmth described in other reviews saying it's not suitable for above 0, etc... it's just a good thermal, if you find it for 40 euros, grab it

The thermal does what it promises but be careful: it's not for above 0 degrees. It's for very cold weather, so if you plan to wear it in 0 to 5 degrees, prefer something else unless you want to wear it alone, which I don't know if is convenient for layering. I have taken the merino 200 from the same company and I prefer this one for around 0.

It was tested in very low temperatures and it always kept the temperature in the core. Also, a tremendous feeling on the skin.

One of the warmest thermal tops you can buy. There are few on the market with such insulation. However, be careful, it's not for every day of winter, especially in Greece, when the temperature is above 4-5 degrees it becomes unbearable and definitely not intended for sports activities.
When it comes to cold, we're talking about an incredible product, I wore it in Austria at -3 degrees with just a jacket on top and most of the day I had to take off the jacket.

By far the best thing I have worn.
I live in Norway and work outside in -20 degrees.
I wear the thermal underwear, a thin fleece shirt, and the jacket which is a nylon from the series.
I don't feel anything, it's awesome.

Finally, I found a truly warm garment. It is quite thick as it has fleece on the inside and you feel like you are wrapped in a blanket. It is worth 100%. I wear it at -20°C in Florina, that says it all.