Up until a few years ago I didn’t know what base layers were. I layered up in winter with vest tops and t-shirts and wondered why the layers weren’t keeping me warm. When I did finally discover that base layers existed, I became duly obsessed. I’ve been a bit of a merino convert recently, so when I was sent a free SubZero base layer to test out that wasn’t merino, I was intrigued.

Cold, cold

I have Raynaud’s Phenomenon which means my hands and feet go numb stupidly fast. Getting the milk from the fridge, standing stationary outside for more than five minutes and even just sitting inside for long periods of times. So keeping warm is a priority.

My usual go-to base layers are 100% merino wool and from Icebreaker and Mons Royale and my go-to sports are hiking, mountain biking, sailing, rock climbing and skiing. Sometimes, when it’s really cold, I wear base layers just hanging around the house…

Technical and functional

I’d never heard of SubZero before they got in touch so I did some research on them and spoke to them about their aims. They said they came from a textile engineering background rather than a design background, so that their garments are super functional but not aesthetic design-orientated.

This suits me down to the ground. Base layers are base layers, I don’t need funky sketches, mountain prints or the worst, hibiscus flowers, covering my fabrics. I want a neutral colour that works. Which is exactly what SubZero are aiming for.

Subzero base layer review

SubZero Base Layer

SubZero sent me the Factor 1+ seamless base layer, long-sleeved and in XS. I was pretty skeptical that it would be small enough since I usually wear size 4-6 (depending on the shop) but actually it fit really well.

Considering I’m obsessed with merino, the feel of fabric is really important to me. Made from a polyamide yarn, the Factor 1+ base layer is super soft. As in, softer than merino. Which I was really surprised about. It’s also made with some waffly sections and ribbed sections which you can see below.

base layer fabric

Mountains + October

I took this base layer out for a savage mountain bike ride the day after I received it- I figured I’d put it through its paces. Welsh trail riding on a chilly October day was definitely a good call considering I got pretty sweaty on the 2 hour ascent and had cold wind whistling past me on the descent.

The SubZero base layer has been impregnated with a hydrophilic treatment and wicks sweat so well that I never even felt damp on the climb even though my face was dripping with sweat. Because it wicked so well, every time I stopped for a snack (let’s face it, pretty regularly), I didn’t instantly cool down either.

For the entire ride I only wore this base layer on my top half as well as a small backpack. It was perfect for the seemingly endless ascent, snack breaks and the fast downhill. In fact, I didn’t get cold at all and my back didn’t suffer that usual horrible sweat you get from wearing a backpack without mesh.

Not a Smelly Helly…

Since I was staying overnight in the mountains, I didn’t get a chance to wash my clothes until over 24 hours later and this is one reason why I love merino usually – the stuff just doesn’t smell. Expecting the SubZero base layer to be as smelly as a classic Helly Hansen after just a few hours, I was amazed to discover that it didn’t smell at all, even after it had been festering in a bag overnight for two nights in a row.

I’ve since taken this out hiking and had the same experience; a comfy, warm base layer that wicks sweat but doesn’t make me cold the second I stop and the wind picks up.

subzero base layer

Less money, more benefits

At the time of writing, the Factor 1+ women’s base layer was £44.99 full price which is pretty good considering a comparative Icebreaker base layer is pushing £100. SubZero do have merino base layers as well but I’m pretty hooked on this one and the fabric feels a hell of a lot stronger than merino.

And the best thing…

It has thumb loops.

Need I say more?

thumb loops base layer

Does it get to stay?

Not only is this a great base layer for mountain biking and hiking, I really like wearing it whenever I’m chilly. It’s so soft and comfortable that I forget I’m wearing a piece of technical clothing. It’s not super snug on me because I’m a little small for the smallest size but it still performs really well and would definitely suit someone sized 6-8.

Being black, it’s easier to wear than the crazy colours of Mons Royale and I’m so scared about nicking the fabric of my expensive Icebreaker that I end up not wearing it that much. This SubZero base layer is definitely going to be my go-to base from now on with all its warm waffly-goodness.

Do you have any favourite base layers you can recommend and have withstood some serious punishment? Let me know!

Thanks so much to SubZero for reaching out and sending me this base layer to try for free. I was such a merino stick-in-the-mud that I might not have tried it otherwise!