The Best… Base Layers – Reviewed

It’s well known that layering your clothing is the best way to maximise your comfort in the outdoors. If you’re working hard, remove a layer. If you have to endure a 20 minute chairlift in an icy wind, add a layer. It’s a straightforward concept that allows you to react quickly to changes in your level of activity or the weather. The base layer sits against your skin and insulates and wicks away moisture, playing an essential role in regulating your body temperature.

By wicking perspiration away from your skin your base layer will keep you dry and help you maintain a cool body temperature in summer and retain heat in winter. If you combine a good base layer with a breathable waterproof shell, you’ll avoid that uncomfortable damp feeling you get from wearing a cotton t-shirt under a raincoat.

Brands like Helly Hansen and Icebreaker place their main focus on producing high performance and high quality base layers. More expensive lines use natural fabrics like merino or cashmere wool, whilst many top brands opt for synthetic fabrics, usually polyester based, such as DRSKIN Aerocool or Patagonia Capilene. You’ll also find base layers that use a blend of natural and synthetic fibres.

Rather than absorbing moisture, these materials move moisture away from your skin, dispersing it on the outer surface where it can evaporate. That means you stay dry even when you’re working hard and your shirt dries faster afterwards. In terms of moisture wicking functionality, you may find that a modern synthetic fabric outperforms a pure wool alternative. But, a merino base layer will naturally resist odour and won’t smell too bad after a day on the hill, whereas a synthetic base layer will smell terrible. A blend of fabrics will aim to offer the best of both functionality and comfort.

A base layer can be tight or loose fitting. Runners may prefer a tight fitting compression base layer, made popular by athletes like Allen Iverson, that will combine temperature regulation and wicking properties with the purported ergogenic benefits. Base layers are available in different weights depending on your activity and the temperature. Choose a lightweight, thinner material for summer and a thicker, heavier base layer for winter sports.

Here we review some of the best base layers available:

Mountain Warehouse Merino Base Layer

Great for autumn biking, hiking or under a ski jacket on the pistes, this merino base layer is smart enough to wear every day and will quickly become one of your favourite items of clothing. Natural wool insulation complimented with the wicking performance of polyester means it will keep you warm and dry. The fine weave feels comfortable next to the skin and the quarter length zip is good for ventilation and adds an element of style. During activity, it will keep you warm in 7 to 10 degrees – any colder and you may need to add a layer. Easy to care for and washes well on a 30° cycle.

Fabric: 80% Merino, 20% Polyester
Machine washable: Yes
RRP: 59.99 EUR | 49.99 GBP | 59.99 USD

Available from: Amazon

Icebreaker Oasis 200 Merino Base Layer

This mid-weight crew neck base layer is a superbly versatile piece of kit. Wear it hiking, biking, running or under a ski jacket and you’re pretty much guaranteed a comfortable day in the outdoors. Made from a fine weave of soft and naturally breathable New Zealand merino wool, Icebreaker have paid great attention to making sure the shirt feels pleasant against the skin. Shoulder seems have been off-set to prevent your backpack rubbing and the garment’s seams are flatlock stitched to prevent chafing. Icebreaker base layers are so good at resisting odour that you could wear this shirt multiple days in a row, so ideal if you need to pack light for an expedition. Pricey but worth it.

Fabric: 100% Merino
Weight: 200g/m²
Machine washable: Yes
RRP: 85.95 EUR | 60.00 GBP | 90 USD

Available from: Amazon

Helly Hansen Dry Stripe Crew Base Layer

The HH Dry Stripe shirt is the original base layer in Helly Hansen’s lineup of technical garments. HH have spent the last 40 years perfecting their Lifa Stay Dry technology which is a fabric made from 100% polypropylene and works by wicking away perspiration and creating a dry layer next to the skin. It works really well keeping you comfortable even during highly aerobic activities. This is a lightweight shirt and can be worn throughout the year, on its own in warmer months or as an insulating layer when the temperature drops. Tight fitting with flatlock stitching and fitted cuffs that don’t ride up, this shirt will become a firm favourite whenever you’re exercising outside.

Fabric: 100% Polypropylene (HH Lifa® Stay Dry)
Weight: 125g/m²
Machine washable: Yes
RRP: 40.00 EUR | 30.00 GBP | 39.90 USD

Available from: Amazon

Patagonia Capilene Midweight Crew Base Layer

If you’re keen to find a synthetic base layer that has its environmental credentials intact, it’s hard to look past the Patagonia Capilene. Corporate responsibility is at the core of what Patagonia do and the fabric uses 63-93% recycled-polyester, which is basically old plastic bottles. The Capilene Midweight base layer is designed to keep you dry and comfortable during high exertion activities in cool to moderate temperatures. I have one that I use for mountain biking throughout the winter. The regular fit is quite loose compared to a Helly Hansen Dry Stripe, but there’s the same attention to detail when it comes to comfort and performance. The fabric has a brushed grid pattern on the inside to improve moisture wicking as well as warmth, three are offset shoulder seams to eliminate chafing under backpack straps and full underarm gussets for full shoulder mobility. And, to keep your tent partner from kicking you out, Patagonia has treated the fabric with a very effective odor control.

Fabric: 100% Polyester (with Polygiene® odor control)
Weight: 189g/m²
Machine washable: Yes
RRP: 69.90 EUR | 50.00 GBP | 78.95 USD

Available from: Amazon

Under Armour HeatGear® Long Sleeve Compression Shirt

Under Armour’s compression base layer combines excellent breathability with second skin support that makes you feel like you can perform better than you could without it. Sceptics might say it’s psychological, but the science does back it up and Under Armour have produced a super-lightweight fabric that provides very reassuring support. Great for intensive exercise, the shirt wicks away sweat and does a great job of keeping you feeling cool and dry. As this is a compression shirt, for the perfect fit Under Armour advise you to go one size bigger than usual.

Fabric: 100% Polyester/Elastane
Weight: 140g/m²
Machine washable: Yes
RRP: 35.00 EUR | 30.00 GBP | 34.99 USD

Available from: Amazon

Minus33 Merino Wool Women’s Ossipee Base Layer

This crew cut midweight base layer from Minus33 is guaranteed to keep you nice and toasty. 100% merino wool means there’s great natural temperature regulation and it will provide warmth worn on its own or on a cold, blustery day it lends itself to being integrated with other layers. The 230g merino wool isn’t as fast to dry as a synthetic alternative such as the Patagonia Capilene, but for comfort and breathability it’s hard to beat.

Fabric: 100% Merino Wool
Weight: 230g/m²
Machine washable: Yes
RRP: 65.99 EUR | 62.99 GBP | 65.99 USD

Available from: Amazon

Smartwool Men’s NTS Mid 250 Base Layer

If you want warmth without the bulk, this merino layer is the answer. It’s lightweight and manages to keep you warm and cool at the same time thanks to its excellent fast drying wicking properties. You can wear it on its own in late spring and early autumn or as part of your layering system in the winter. Flatlock seams and shoulder panels are designed to eliminate chaffing during sport. The length at the sleeves and lower back will suit taller people, but if you’re looking for a ‘fitted’ base layer, you may want to size down.

Fabric: 100% Merino Wool
Weight: 250g/m²
Machine washable: Yes
RRP: 104.95 EUR | 84.99 GBP | 95.00 USD

Available from: Amazon