Fabric weight guide
Which merino weight is right for you?
GSM is grams per square metre — how much fabric there is, not a warmth rating. Every weight is the same soft 17.5-micron Australian merino: it wicks sweat before it turns cold, insulates when it is cold and ventilates when it is warm. Lighter fabric breathes and dries faster; heavier fabric holds more heat when you stop moving. Choose by season and by how hard you will be working.
Warm & hot weather · 60°F+ / 15°C+ — and high effort in any season
Best for: summer hiking, running, cycling, hot-climate travel, everyday tees and office wear; the next-to-skin layer under a 250 when you work hard in winter
Pick this if: you want a shirt that stays fresh for days, dries in an hour and keeps you cooler than cotton in the heat — or you simply run hot
Think twice if: you will mostly be standing still in the cold; on its own a lightweight layer has little insulation to offer
Shop 165 GSM →Cool to mild · 40–65°F / 5–18°C
Best for: spring and autumn as a standalone top, summer evenings, cool-morning hikes and commutes; winter as a base under a mid-layer
Pick this if: you want one merino layer that covers most of the year, or you are unsure between light and mid — this is where most people should start
Think twice if: you run cold and your winter is genuinely cold: go straight to 250
Shop 190 GSM →Cold · 20–45°F / −7–7°C — the classic winter base layer
Best for: skiing and snowboarding, winter hiking, cold-weather work, frosty autumn mornings; top-and-bottom sets so your legs are not the weak link
Pick this if: you run cold in fall, want the classic winter base layer, or spend active days below freezing under a shell
Think twice if: you overheat easily on hard uphill efforts — a 165 or 190 underneath, 250 over it, is the better system
Shop 250 GSM →Deep cold · below 25°F / −4°C — especially when you stop moving
Best for: ice fishing, hunting stands, camp at altitude, winter mornings spent waiting rather than walking, a house that never quite gets warm
Pick this if: warmth matters more than breathability, you are chronically cold, or your winter involves long spells standing still outdoors
Think twice if: you will be working hard — it is too warm for a sweaty climb, which is exactly the point
Shop 320 GSM →A base layer works by sitting close to the skin, where it can move moisture — loose is not more comfortable, just slower. Between sizes? Size down for a next-to-skin layer under a shell, size up to wear it on its own or over another layer. Merino stretches with wear and springs back after a wash. Heavier weight is not itchier: itch comes from coarse fibre, and every weight here is the same superfine merino.
Size guide
Size Guide
Our merino has a close, next-to-skin fit by design. If you are between sizes, stay true to size for base-layer use or size up for a more relaxed everyday fit. Free returns within 30 days, so ordering two sizes and sending one back is completely fine.
How to measure
Chest — around the fullest part of your chest, with the tape level under the arms.
Waist — around your natural waistline, with the tape comfortably loose.
Hips — around the fullest part of your hips and seat.
Inside leg — from the top of your inner thigh to your ankle bone.
Measure over light clothing, keeping the tape snug but not tight. Tap any chart below to open it full size.
Men's Base Layer Set
Need different sizes for the top and the bottoms? Build your own set →
Women's Base Layer Set
Need different sizes for the top and the bottoms? Build your own set →
Kids' Base Layer Set
Men's T-Shirt
Women's T-Shirt
Men's Long Sleeve
Same body measurements across 165, 190, 250 and 320gsm.
Women's Long Sleeve
Kids' Long Sleeve
Men's Long Johns
Women's Thermal Leggings
Kids' Thermal Leggings
Men's Half Zip
Women's Half Zip
Merino Wool Socks
Beanies, snoods and balaclavas
Still unsure which size to pick? Email info@merinotech.co.uk with your height, chest and waist and we will recommend a size. Free UK delivery over £49 and free returns within 30 days.
- Free shipping over $49.99
- 30-day easy returns
- Ships in 1–2 business days
Description
Women's Merino Long Sleeve
Built for adventure, perfected for comfort. The Women’s Merino Wool Long Sleeve keeps you warm, dry, and fresh — no matter where your day takes you. Merino fibres manage heat and humidity naturally, so you’ll stay cool when you’re active and warm when you rest.
Thanks to its odor-resistant and moisture-wicking properties, you can wear it for multiple days without washing — ideal for travel or hiking. Lightweight, soft, and compact, it fits easily in any backpack while maintaining its shape and beauty after every wear.
Care
Turn inside out. Machine wash cold on a gentle cycle with a wool-safe detergent. Do not bleach. Lay flat or hang to dry.
Shipping & returns
Free UK delivery on orders over £49. Ships in 1–2 business days. 30-day free returns on unworn items with tags.
Women's long sleeve base layer
Built for layering, worn on its own
A close, next-to-skin fit with flatlock seams and a long body that stays tucked. Wear it alone on cool days or as the first layer under a shell when it really gets cold.
Size guide
Women's Long Sleeve 250
Fit
A close, next-to-skin fit that is true to size for a base layer. Between sizes? Stay true to size to wear it under other layers, or size up for a more relaxed fit on its own.
How to measure
- Chest – around the fullest part of your chest, tape level under the arms.
- Waist – around your natural waistline, tape comfortably loose.
- Hips – around the fullest part of your hips and seat.
- Inside leg – from the top of your inner thigh to your ankle bone.
Measure over light clothing and keep the tape snug but not tight. Still unsure? Email info@merinotech.co.uk with your height, chest and waist and we will recommend a size. Unworn items can be returned free within 30 days.
THE FABRIC
Why merino wool
Merino wool moves sweat away from your skin as vapour and lets it evaporate from the fabric, so you stay dry and comfortable whether you are hiking, commuting or skiing.
Merino fibres naturally resist the bacteria that cause odour, so you can wear a base layer for several days, on the trail or while travelling, and it still smells fresh.
Wool can absorb up to 30% of its weight in moisture without feeling wet. In damp British weather it keeps insulating where cotton and polyester leave you cold.
Merino absorbs UV radiation: our lightweight layers offer UPF 25 and the midweight and heavyweight options UPF 50+, handy on long days in the hills.
Merino wool is naturally hard to ignite and self-extinguishes without melting onto the skin, unlike synthetic base layers.
Merino is a natural, renewable and biodegradable fibre. Sheep grow a new fleece every year, and a worn-out merino garment breaks down instead of shedding plastic microfibres.
FAQ
Women's merino base layer tops: FAQ
What is this 250gsm base layer top best for?
It is a midweight 250gsm merino layer, best for skiing, hiking and cold UK winters. Compare every weight in our merino weight guide.
Is this base layer top warm enough for skiing?
Yes. 250gsm midweight merino under a ski jacket and trousers is the most popular choice for a ski holiday. Choose 320gsm if you feel the cold.
Which weight of women's merino base layer should I choose?
165gsm lightweight is best for spring, summer and active days; 190gsm is a versatile year-round top; 250gsm midweight is the go-to winter base layer for walking, skiing and cold commutes; 320gsm heavyweight is for very cold weather and low-activity days outdoors. See the weight guide.
How do women's merino tops fit?
They have a close, feminine fit that sits smoothly under other layers. They are true to size; if you are between sizes, size down for a snug base layer or size up to wear the top on its own. Use the size guide to compare measurements.
Can I wear a merino base layer as an everyday top?
Yes. Scoop neck, V-neck and turtleneck styles look like a regular long sleeve top, so you can wear them to work or travel and still get the warmth and odour resistance of merino.
Is merino wool good for sensitive skin?
Our superfine 17.5-micron merino is soft and non-itchy, and many people who cannot wear ordinary wool find it comfortable next to the skin. It is also breathable, which helps avoid the clammy feel of synthetic thermals.
How do I wash a merino top?
Inside out at 30°C or lower on a wool or delicate cycle with a wool-safe detergent, no fabric softener, then dry flat or on a hanger. Do not tumble dry.
I just love all my long sleeve t-shirts. They wash well and are super comfortable! This one I wore in low 50's temp, and it kept me warm!
I just love all my long sleeve t-shirts. They wash well and are super comfortable! This one I wore in low 50's temp, and it kept me warm!
I love it. I posted a video review on Instagram but have not received the 20 percent discount code yet.
Lovely warm base layer. Called "olive", but the actual colour is very much like the photo, a rich forest green, almost kelly green. Very stretchy and forgiving, material, I may size down in the future.
The free socks were a nice addition, but I ordered multiple items and wasn't expecting to receive a pair of socks with each item. That's a lot of socks! They're very plush and warm. I only wish they'd let me choose the size for the socks, since they all appear to be gender-neutral (aka men's sizes) and I was sent mostly medium, which were way too big, and a couple pairs of large... I may have to hold onto them for a decade or so, to gift them to my kid once he grows into them.
Lovely warm base layer. Called "olive", but the actual colour is very much like the photo, a rich forest green, almost kelly green. Very stretchy and forgiving, material, I may size down in the future.
The free socks were a nice addition, but I ordered multiple items and wasn't expecting to receive a pair of socks with each item. That's a lot of socks! They're very plush and warm. I only wish they'd let me choose the size for the socks, since they all appear to be gender-neutral (aka men's sizes) and I was sent mostly medium, which were way too big, and a couple pairs of large... I may have to hold onto them for a decade or so, to gift them to my kid once he grows into them.
Absolutely beautiful colour and extremely warm very soft gonna be a staple to my wardrobe
Absolutely beautiful colour and extremely warm very soft gonna be a staple to my wardrobe
They are warm and soft.
They are warm and soft.
Have worn it for several days in a row just to check out the claims about no odour and it is true! It not only had no smell but was softer than expected.
Have worn it for several days in a row just to check out the claims about no odour and it is true! It not only had no smell but was softer than expected.
I absolutely love the 250 tops. I wear them for every possible activity, from athletics to dress up to sleeping… I spend all the cold weather months in them, all the time! The only reason I’m not giving it five stars is that I wish we could mix and match sizes for the top-and-bottom sets. I’m pear-shaped, and take a size S on top, but a size M for the leggings. I wish I could take advantage of the discounted price for the sets,
I absolutely love the 250 tops. I wear them for every possible activity, from athletics to dress up to sleeping… I spend all the cold weather months in them, all the time! The only reason I’m not giving it five stars is that I wish we could mix and match sizes for the top-and-bottom sets. I’m pear-shaped, and take a size S on top, but a size M for the leggings. I wish I could take advantage of the discounted price for the sets,
Makes a great top as well as an underlayer, because it looks shapely and sharp.
Makes a great top as well as an underlayer, because it looks shapely and sharp.
Great product. Soft and warm. Product is well made.
Great product. Soft and warm. Product is well made.
This product is soft and warm.
This product is soft and warm.
Beautiful colour and they fit great
Beautiful colour and they fit great
Wonderful feel! Fast shipping! Thanks!
This shirt is huge in the torso and too tight in the arms.
This shirt is huge in the torso and too tight in the arms.
Wonderful feel! Fast shipping! Thanks!
I love this long sleeve shirt so much. It's so soft and very comfortable. I've been buying only natural material clothing and this shirt is a perfect fit for me.
I love this long sleeve shirt so much. It's so soft and very comfortable. I've been buying only natural material clothing and this shirt is a perfect fit for me.
Love love love!! So soft.
Love love love!! So soft.
I purchased this sweater in green after wearing it in other colours for several months. They have become staples in my wardrobe for fall, winter and spring. They are a perfect weight for layering or wearing alone. So soft, incredibly comfortable. The seams along the torso make it very flattering, even with a large bust. I have found them to last several wears between machine washes in cold water, and they still look as good as new. I love these for traveling and make packing light and looking polished very easy. The "olive" is a gorgeous rich kelly green.
I purchased this sweater in green after wearing it in other colours for several months. They have become staples in my wardrobe for fall, winter and spring. They are a perfect weight for layering or wearing alone. So soft, incredibly comfortable. The seams along the torso make it very flattering, even with a large bust. I have found them to last several wears between machine washes in cold water, and they still look as good as new. I love these for traveling and make packing light and looking polished very easy. The "olive" is a gorgeous rich kelly green.
