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
Meet the long sleeve that does it all. Crafted from premium Merino wool, it offers the perfect balance of warmth, ventilation, and style. The superfine fibres provide a silky-smooth feel with zero itch, while natural elasticity ensures the top retains its shape wear after wear.
Merino wool actively wicks away moisture, neutralizes odour, and protects against UV rays — making it your essential companion for outdoor life and everyday comfort. Ethically made and fully biodegradable, it’s a sustainable choice that never compromises on performance or beauty.
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.
Which sizes are in stock?
Available to order now: , S, M, L. Our merino is true to size and designed to sit close to the skin; see the size guide for measurements.
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 ordered 3 of these in different colours. I love these long sleeve tops! It seems to have softened after washing and I am using it for my morning walks and hikes!!
I am loving my top. It feels like a hug. It’s a good thing I can wear it multiple times before I need to wash it cuz I sure will wear it a lot!
Love the color! The material is soft and feels like good quality.
Haven’t taken it off since receiving it…perfect weight, fit, and color…
Haven’t taken it off since receiving it…perfect weight, fit, and color…
I like it but it doesn't feel as silky as merino wool.
I like it but it doesn't feel as silky as merino wool.
Once again I am extremely impressed with this brand. The material is soft and just the right thickness. I'm an average size but do find the arms just a little more snug than to my preference. I wear it as a base layer under my sweaters I would purchase again.
Once again I am extremely impressed with this brand. The material is soft and just the right thickness. I'm an average size but do find the arms just a little more snug than to my preference. I wear it as a base layer under my sweaters I would purchase again.
The Merino Tech 250 Chocolate long sleeve shirt is very comfortable and keeps me pleasantly warm.
The Merino Tech 250 Chocolate long sleeve shirt is very comfortable and keeps me pleasantly warm.
I love the shirt, true to size, unlike the socks. Made in China so I will NEVER purchase again
I love the shirt, true to size, unlike the socks. Made in China so I will NEVER purchase again
Chocolate coziness...softness as good as it gets!
Chocolate coziness...softness as good as it gets!
I ordered 3 of these in different colours. I love these long sleeve tops! It seems to have softened after washing and I am using it for my morning walks and hikes!!
I’ve owned them in a few colours, and I love this one (it wasn’t available on Amazon). They are so soft, warm, not itchy, and wash nicely. I am so hooked!
I’ve owned them in a few colours, and I love this one (it wasn’t available on Amazon). They are so soft, warm, not itchy, and wash nicely. I am so hooked!
I am quite pleased with the quality of this product. The material is quite luxurious and I know it will keep me warm. thank you for this great product. I bought many …
I am quite pleased with the quality of this product. The material is quite luxurious and I know it will keep me warm. thank you for this great product. I bought many …
It feels so good the moment when you put it on. Keeps you warm and is very comfortable.
It feels so good the moment when you put it on. Keeps you warm and is very comfortable.
Women's Merino Long Sleeve 250 Chocolate
Women's Merino Long Sleeve 250 Chocolate
I love this shirt. It is warm because of the wool, but thin and lightweight, which is just what I wanted. I wear it for exercise or layered under another top. Fortunately I ordered a larger size than I normally would, and it fits perfectly.
I love this shirt. It is warm because of the wool, but thin and lightweight, which is just what I wanted. I wear it for exercise or layered under another top. Fortunately I ordered a larger size than I normally would, and it fits perfectly.
The quality seems good, I used the size chart to order, but it runs big. I'm a medium but will order a small now.
The quality seems good, I used the size chart to order, but it runs big. I'm a medium but will order a small now.
This is a GREAT part of my layering for Winter! It blocks the wind from getting through & keeps the warmth in. I am VERY pleased with this 🤩
Comfortable as I was wearing under another garment.
I have only worn this twice but so far seems as nice as the name brand one I bought a few weeks earlier. It seems as thick as my other 250 ct and washes without shrinking. I would buy another.
This is a GREAT part of my layering for Winter! It blocks the wind from getting through & keeps the warmth in. I am VERY pleased with this 🤩
