18 Best thermal base layers for women

WHEN winter rolls around and the temperatures drop you need extra layers to keep out the cold and that’s where a pair of the best thermals come in.

They add extra warmth, yet are unobtrusive and don’t make you feel over-dressed. You need to be able to move freely, without feeling restricted by the extra tee and leggings under your regular clothes and your skin needs to be able to breathe under the extra coverage.

Thermals are available in a range of fabrics, so whether you’re a natural fibres fan or mad about manmade, there’s something to suit you.

Both manmade and natural fibres have their plus points. Many synthetic fibres are high-tech, designed to be breathable and wick away moisture from the surface of your skin so sweat doesn’t stay trapped, making you feel cold.

A natural fibre, such as Merino wool, is ideal in a base layer because it keeps you warm when you’re cold and cool when you’re hot. Merino also doesn’t need washing as often as other fibres because its in-built anti-bacterial properties prevent odour.

Finally, consider the fit: if the base layer is too baggy then you’re going to be uncomfortable. I found the best fit was one where the thermals lay close to my skin. Indeed, some of the products I tested were skintight but had built-in stretch and were a dream to wear.

Best thermal base layers at a glance:

• Best top:
• Best leggings:
• Best value top:
• Best value leggings:

Animal Piste Women’s Base Layer Leggings

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• Animal Piste Women’s Base Layer Leggings, £30 from Animal –

Pros: Lightweight but really warm, close fit, comfortable

Cons: None

Rating: 5/5

As soon as I put these on I loved these leggings. They feel like a second skin and they are sooo comfortable!

They kept me warm and snug in a few days of horribly cold winds and torrential rain, which threatened to turn my usually happy dog walks into a chore.

The fabric is so light and when I first unwrapped them I was dubious as to just how warm they would be. From the outside, they look almost see-through, yet the underside of the material is super soft against your skin.

They’re a great length for me, reaching past my ankles, and they have a good amount of stretch. They don’t go saggy at the knees, even after wearing them all day and the fabric just pings back into shape.

They're made from recycled fabric and wash well in a 40° cycle.

Size: 6 – 24; Material: 89% recycled polyester and 11% elastane; Colours: black

Acai thermal Seamless Base Layer Top

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• Acai thermal Seamless Base Layer Top in Laurel, £49 from Acai –

Pros: Good length, figure-hugging, very warm, long sleeves with thumb holes

Cons: None

Rating: 5/5

This long-sleeved top is made from a fabric with an incredible amount of stretch. It sits close to your body but is very flexible and, as an added bonus, the long sleeves have thumb holes, which are great for extra warmth over your hands when the weather’s freezing.

It’s designed for the outdoors (think winter hikes and camping) so as you can imagine, it keeps you warm. There are no seams on the body so there’s nothing to rub or chafe and the crew neck is high so keeps out draughts.

Akai says the fabric uses “NILIT Heat yarn technology”, which is made by “integrating coffee charcoal waste from coffee bean shells with nylon fibres”. The result is a fabric with anti-bacterial properties that wicks away moisture to keep you dry while holding in heat; impressive.

It’s available in six colours, including the lovely Laurel shade I tested.

Size: XS – XL; Material: 60% polyamide, 34% polyester, 6% elastane; Colours: Laurel, aubergine, petrol blue, deep navy, black and charcoal

TOG24 Meru Women’s Cashmere Touch Base Layer Roll Neck

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• TOG24 Meru Women’s Cashmere Touch Base Layer Roll Neck in Off White, £30 from TOG24 –

Pros: Affordable, soft-feel fabric, really warm, roll neck added extra warmth

Cons: None

Rating: 5/5

This rollneck stood up to bitterly cold winds on the days I tested it. I was grateful for the higher neck even though I wouldn’t usually wear that style of top, normally finding them too tight. This one, however, is a slouchy kind of roll neck and is incredibly comfortable to wear.

The fabric is an acrylic viscose blend and the underneath is ever so soft against the skin. It really did hold in the heat and it was a joy to wear. I tested the size 14 and the fit was not too tight and worked well under jumpers. It was also easy to wash; I just popped it in the machine on a 30° delicate programme and hung it on the airer to dry.

Size: 8 – 16; Material: 60% acrylic, 40% viscose; Colours: Off-white

M&S Heatgen Medium Thermal Long Sleeve Top

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• M&S Heatgen Medium Thermal Long Sleeve Top, £16 from M&S –

Pros: Great fit, great stretch, great price, lots of colours

Cons: None I can see

Rating: 5/5

This long-sleeved top is understated in every way, except how it performs. The classic design with wide scoop neck is flattering and looks more expensive than it is. The smooth jersey finish is soft and smart, while the underside of the fabric is brushed and has a velvety feel.

The addition of elastane to the acrylic and viscose fabric brings welcome stretch and the fit is pleasantly close.

I tested this in navy and I love how warm it is, as well as how it looks; the length is also perfect as it covers your bum for added heat when it’s cold.

This top is available in eight colours, including cerise, dusty green and moss as well as the usual darker shades, so you should be able to find a colour to fit with whatever you’re wearing. Love it!

Size: 6 – 22; Material: 64% acrylic, 28% viscose and 8% elastane; Colours: Navy, black, rose quarts, bitter chocolate, redcurrant, light cream, dusty green and dark raspberry

Smartwool Classic Thermal Merino Base Layer Bottom

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• Smartwool Classic Thermal Merino Base Layer Bottom, £99.99 from Smartwool –

Pros: Ethically sourced Merino wool, lightweight and warm, moisture wicking

Cons: None

Rating: 5/5

These lovely lightweight Merino wool leggings are the ideal base layer for when the weather’s cold.

I tested the purple iris heather colourway in medium and loved them. They fit close to the skin and have a medium-width waist that doesn’t roll down. They were long enough to cover my ankles and so comfy to wear.

Because the knit is fine, they’re not baggy under trousers and I didn’t notice any pilling where the leggings came into contact with my jeans.

Although they’re made from 100% Merino wool, they’re machine washable on a gentle cycle and can be tumble dried at a low temperature, though I prefer to dry them on the clothes airer.

Crucially as far as I’m concerned, the wool is also sustainably sourced from farms with high standards of animal welfare and no mulesing.

Size: XS – XL; Material: 100% Merino wool; Colours: Purple iris heather, winter sky heather, twilight blue heather

George Ivory Super Soft Pointelle Long Sleeve Thermal Top

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• George Ivory Super Soft Pointelle Long Sleeve Thermal Top, £10 from George at Asda –

Pros: Good length, very warm, soft, pretty pointelle design

Cons: None

Rating: 5/5

This is an amazing base layer for the price. It's made from a blend of polyester and viscose, meaning it's lightweight but feels thick because of the brushed inside.

It’s very warm: a couple of days when I wore this the temperature was -2°C but I didn’t feel the cold and found it super soft against my skin.

The long sleeves have a narrow elasticated band at the wrist, which held them close to my arms and the pointelle design is very feminine. The deeper round neck also means the top doesn’t show above any outer layers.

Size: 6 – 22; Material: 50% polyester, 50% viscose; Colours: Ivory

Helly Hansen Women’s LIFA Merino Midweight 2-in-1 Base Layer Hoodie

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• Helly Hansen Women’s LIFA Merino Midweight 2-in-1 Base Layer Hoodie, £100 from Helly Hansen –

Pros: Length, hood and high neck, lovely colour

Cons: Price

Rating: 4.5/5

Helly Hansen is a specialist in outdoor sports and its LIFA Merino Midweight 2-in-1 base layer is designed to perform in cold temperatures.

It’s made from a mix of Merino Wool and Polypropylene, with the wool on the outside and the moisture-wicking polypropylene on the inside. Importantly, the company only sources its Merino wool from farmers with high animal welfare standards and there’s no mulesing.

I chose the bright blue colourway to test and it looks great. The neck is high to keep out the cold and the hood is a welcome addition when it’s windy, but it does fit close, which I found a little restricting (although perfect if you’re skiing).

This wasn't quite as warm as I expected it to be, however, I love the colour and the sustainability factor and will definitely wear this in future.

Size: XS – XL; Material: 57% Merino wool, 43% polypropylene; Colours: Bright blue and black

La Redoute Collections Thermal Vest Top

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• La Redoute Collections Thermal Vest Top in Cotton Mix, £19.20 from La Redoute –

Pros: Warmth without the volume, price

Cons: Could be longer length

Rating: 4/5

This pretty vest top is a great alternative if you’re not a fan of long sleeves or simply want added warmth without the bulk.

It’s sleeveless with a cutaway shape to the arms and a deep V neck edged with lace. I wore this under a jumper but it would also work under a dress and you could wear it under a shirt for work.

I was surprised at just how warm it was. The fabric contains 35% wool, which probably explains it, as well as cotton and viscose. My only (little) gripe is that I would have preferred it to be a bit longer.

Size: 6 – 24; Material: 50% cotton, 35% wool, 15% viscose; Colours: Black and ecru

Mountain Warehouse Bamboo Women’s Round Neck Top

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• Mountain Warehouse Bamboo Women’s Round Neck Top, £19.99 from Mountain Warehouse –

Pros: Length, warmth, price

Cons: None I can see

Rating: 5/5

When I tested this top it was something like -3°C and it kept me warm despite the stupidly cold weather.

It’s a bamboo cotton mix fabric which wicks away moisture from the skin, though it didn’t need to do that the days I wore it as there was no chance I was going to sweat.

It’s a great length for tucking into trousers and the sleeves are long enough to cover part of your hands if you want them to.  Don’t worry though, the cuffs sit close to your wrists so don’t slip down unless you pull them over your hands.

The jersey fabric is the same on the inside as the outside, it’s not brushed but that doesn’t detract from the warmth of the top. This is another one that’s stylish enough to wear as a tee as well as a base layer.

Size: 4 – 28; Material: 70% viscose (bamboo) and 30% cotton; Colours: Dark khaki and black

TOG24 Meru Women’s Cashmere Touch Base Layer Leggings

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• TOG24 Meru Women’s Cashmere Touch Base Layer Leggings in Off White, £30 from TOG24 –

Pros: Affordable, very warm, luxuriously soft fabric

Cons: A little baggy at the knees

Rating: 4/5

These leggings match the Meru Base Layer Roll Neck top, which I also reviewed. I tested the leggings in a size 14 and I loved the fit, although they weren’t skintight. I wore them under jeans and found that, after a few hours, they had become a little baggy at the knees, but this is really the only negative thing I could say about them.

The acrylic viscose blend fabric has a jersey-finish on the outside and a butter-soft finish on the inside, just like the roll-neck.

They were slightly long on me, stretching right down to my ankles, which was a good thing as it meant there was no exposed flesh to feel the cold, and they kept my legs toasty warm on freezing-cold dog walks.

Size: 8 – 16; Material: 60% acrylic, 40% viscose; Colours: Off white

Damart Thermal Intense Warmth Long Pants

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• Damart Thermal Intense Warmth Long Pants, £29 from Damart –

Pros: Designed for very cold weather, good length

Cons: The fabric pilled on the front of the leg and also at the inner seams

Rating: 3.5/5

These pants are designed for wearing in the depths of winter, which is just as well with the temperatures we had in December.

I received the black colourway to test and I found them comfortable, if not particularly close-fitting. The length was great for me, but there’s not very much stretch in the fabric. The fabric has an almost knitted feel, with a brushed reverse, which adds to the warmth, and the pointelle design is pretty.

Damart are longstanding experts when it comes to thermal clothing, with their tops and bottoms graded as to how warm they are: 2 is a light warmth best suited to autumn, 3 is medium for winter, while 4 and 5 are intense for when it’s absolutely freezing outside.

These pants were a 4, so intense, but I didn’t notice them being any warmer than the Damart top I tested, which was medium warmth.

Size: S – 2XL; Material: 50% polyester and 50% acrylic; Colours: black, white and grey marl

Damart Thermal Medium Warmth Long Sleeved T-Shirt

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• Damart Thermal Medium Warmth Long Sleeved T-Shirt, £27 from Damart –

Pros: Design and functionality, could be worn as a top layer as well as a base layer

Cons: Fibres cling to the fabric

Rating: 4/5

This long-sleeved top with its lace inset at the neck proves base layers can be pretty as well as functional.

It’s medium warmth but that said, I didn’t notice it being any less cosy than the other base layers I tested. The jersey-feel fabric doesn’t have a brushed back, but that doesn’t seem to matter as it’s warm without it. However, I did find that when I wore the top underneath a jumper then fibres from the jumper clung to it, though they were easily brushed off.

This  top would also work as a t-shirt with jeans and not just a hidden layer for winter.

Made from Damart’s thermolactyl fabric.

Size: XS – 2XL; Material: 50% polyester and 50% acrylic; Colours: black, white, light blue

Smartwool women’s Active Long Sleeve Crew

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• Smartwool women’s Active Long Sleeve Crew, £32.50 from Smartwool –

Pros: Ethically sourced Merino wool, looks great, moisture wicking

Cons: Not quite as warm as I expected

Rating: 4/5

I tested the Active Long Sleeve Crew in Emerald Green, a lovely bold colour that would look great with jeans and not just as a base layer under other clothes.

The fabric is lightweight and is made up of Merino wool and Lyocell (a semi-synthetic fabric mainly made from wood cellulose). Both work together to keep you warm while wicking away moisture.

I tested the medium size and found it a great fit and a good length in the body and the sleeves.

I was also delighted to learn the wool is sourced from farms where the sheep enjoy high standards of welfare where mulesing is not practised.

Size: XS – XL; Material: 53% Merino wool, 47% lyocell; Colours: Emerald green, ultra violet and black

Peter Storm Women’s Thermal Pants

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• Peter Storm Women’s Thermal Pants, £19 from Blacks –

Pros: lightweight, good price

Cons: long on me, a little baggy at the knees

Rating: 3.5/5

These purple thermal pants are made from a viscose and polyester blend. There’s not elastane in them so they don’t bounce back into shape and though they fit close at first, I found that after a while they went a little baggy at the knees.

They’re lightweight but they don’t add that much warmth so I would say they’re better for winter days when the temperature is higher, or for spring walks.

The inside is slightly brushed for a soft feel against your skin. I found them very long, but they’re thin enough to fold up the cuff without creating any annoying bulkiness.

They’re also machine washable at 40°C.

Size: 8 – 18; Material: 65% polyester and 35% viscose; Colours: Purple

Odlo Women’s Performance Light Long Sleeved Baselayer Top

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• Odlo Women’s Performance Light Long Sleeved Baselayer Top, £30 from Blacks –

Pros: very light, warm

Cons: None

Rating: 4.5/5

For me, the key requirements in a good base layer are warmth and a lightweight fabric: this long-sleeved top from Blacks has both.

It’s made from a blend of polyester, polyamide and elastane and it has to be one of the lightest tops I’ve tested. It incorporates ventilation zones within the striped design, so your skin can breathe and the fabric also wicks away moisture, so any sweat produced doesn’t leave you feeling cold and wet.

I’ve worn this for walking and even on a slow run, but it’s also suitable for hiking and winter sports, according to the Blacks’ website.

The length is also good – it’s easy to tuck into your leggings or trousers and it doesn’t ride up.

Size: XS – XL; Material: 63% polyester, 33% polyamide and 4% elastane; Colours: Grey

Peacocks Women’s Plain White Thermal Leggings

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• Women’s Plain White Thermal Leggings, £10 from Peacocks –

Pros: very light, price

Cons: Not very warm

Rating: 3/5

Slightly shorter than full length, these thermal leggings from Peacocks are pretty, featuring a lace cuff and pointelle design.

They are very lightweight and this carries through to their thermal capabilities; they’re not really warm enough for winter wear.

You could argue that any layer is warmer than no layer, which is true, but when the temperatures are around zero or below, you’re looking for something more substantial. I think they’re more suited to spring, when the weather is warmer but the days (and nights) still have a chill to them.

The price however is great and they make for pretty pyjamas when you’re not wearing them as a base layer.

Size: 8 – 24; Material: 50% cotton, 25% polyester and 25% viscose; Colours: White and black

Peacocks Women’s Plain White thermal Short Sleeve Top

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• Women’s Plain White thermal Short Sleeve Top, £9 from Peacocks –

Pros: very light, price

Cons: Not very warm

Rating: 3/5

This is the matching top to the leggings described above. The short sleeves and waist feature a pretty fluted hem and the round neck is edged with lace, adding extra cuteness to the pointelle design.

The fabric is a polyester/cotton/viscose blend and is very lightweight, so though it does add warmth it is not warm enough to keep you toasty on very cold days.

As with the leggings, I think this top is better suited to spring, for wearing on days when there’s still a chill in the air but overall the temperatures are on the rise. However, it’s a good budget buy.

Size: 8 – 24; Material: 50% cotton, 25% polyester and 25% viscose; Colours: White and black