(27 customer reviews)

Made for life

Merino Betatec Long Sleeve Base Layer

Mid weight, reliably warm, super durable merino betatec long sleeve base layer. Award winning and Woolmark certified, guaranteed quality and made for life. Stay warm, light and super breathable during all your outdoor activities. Expect to feel embraced by it’s sumptuous comfort and transcended by its ability to perform as a true technical piece of kit. Whether you are powering up the trails on your chilly morning run or enjoying coffee and cake afterwards with friends, the Merino Betatec is ready to become your companion for life.



Performance Benefits



Thermal Comfort

odor res

Odour Resist


Super Durable

No Itch Wool


Dynamic stretch

Technical Features


Superfine Merino Wool worn next to skin, the perfect buffer for managing moisture and thermal regulation


Pushes the bounderies of what is technically possible in lightweight merino-based products


Total Easy Care convenience. Wear often and wash less saving on water and energy consumption


Engineered Knitting innovation means fewer seams, less waste and dynamic stretch in a snug fit


Machine Washable | Do Not Bleach | Line Dry | Do Not Iron | Do Not Dry Clean

Easy Care Merino Wool

Washes with rest of your kit in a standard machine wash cycle

Wear more wash less


27 reviews for Merino Betatec Long Sleeve Base Layer

  1. paulfoster777 (verified owner)

    Loving my new Loomi merino base layer and beannie! Very stylish, comfy, incredibly well designed and made and also love that the tags and packaging are recyclable.

  2. Lindsay (verified owner)

    Headed to the coast today first run in my Loomi base layer and beanie, the perfect combo, stylish, comfortable, cozy, lovely length of sleeve with enough stretch to easily roll up, they felt great! And as an eczema sufferer, no itch, brilliant!

  3. victoriamorrison1 (verified owner)

    I really love my new base layer, it feels so soft against my skin, much softer than my other baselayers. I also really love the navy and orange…fantastic product!

  4. Jane Logan (verified owner)

    I’ve been wearing my new base layer since it arrived- love it!

  5. Jon Pettifor

    Amazing base layer! I have used on two runs now on it’s own and the fit/ comfort is excellent. I went for a size large and the fit is perfect, nice length in the body and arms and seems really well made. I would love a short sleeve version!

  6. Fiona Shepherd (verified owner)

    A weekend with my baselayer and hat. A wet and windy night hike, a mild 5k run , a sunny and cold long trail run, a dog walk and a trip to the city for brunch. Clothing that fits into my life and goes where I go doing what I need it to do . Extremely comfortable and easy to wear. I highly recommend it’s versatility, quality and wearability Thank you Anne Weir and loomi life 🧡

  7. Louise Johnston (verified owner)

    Love my Loomi. Warm but not too warm, feels like a cozy cuddle the fit is that good! Excellent finish, it doesn’t ride up your back!
    Walking, hiking, running, coffee stops it fits the bill on all accounts.
    Excellent product that’s exceptionally versatile and value for money.

  8. Claire Hendry (verified owner)

    I love my new baselayer. As someone who tends to get very warm when I run, I was a bit worried that it would be too warm for me, but it is perfect and keeps me at just the right temperature. It is a great fit, and so comfortable.

  9. Pauline Ballantyne (verified owner)

    Love my LOOMI garments, not only are they a stylish addition to my wardrobe they are super functional as well. The base layer, beanie and socks kept me company and cosy on a trip to the Highlands last week, they were my staples for this trip. They were put to the test with, 3 trail runs, 4 dog walks and a mountain run/hike, these were worn then air dried ready for the following day there was no itch and passed the whiff test (even at the end of the week) and performed tremendously on the trails! Love the reusable packaging!
    Excellent value for money and a true ‘companion for life’

  10. Daniel O’Shea (verified owner)

    Literally nearly took a shower with my loomi on that’s how conformtable and like a second skin it is – well done great product

  11. Duncan Combe

    Amazing how good this base layer is. Strugged in the past with other brands in this categories. By far the best. 10 out of 10. love the outdoors . From Scotland to the alps . Walking ,hiking, skiing or mountain biking. This base fits the bill Just amazing how good the loomi is .
    Can’t recommend this enough

  12. Catriona Sutherland (verified owner)

    The Loomi baselayer has become a go-to piece of kit. I’m a huge fan of merino and this delivers all the performance I’d hope for, as well as being super easy to care for. As a busy working mum, it’s ideal having a technical top I can keep wearing all day too. Bought one for a friend I loved it so much!

  13. Jen

    My new favourite top, perfect for running, walking the dog and sitting about on the sofa, I don’t think I’ll ever take it off. Excellent fit, flattering fabric that feels like a hug, and super stylish colourway too. 😎

  14. Heather Stoddart (verified owner)

    Loving my new Loomi baselayer. It’s super comfy and fits so well. Perfect for wearing for all my outside activities 😊 🏃🏼‍♀️ 🏇🏻

  15. Agnes (verified owner)

    Love the colour it fits well and so soft next to skin.
    Would recommend.

  16. Kate (verified owner)

    Really comfy, easy wear, love wearing it, in fact I wear it every day!

  17. Debbie Wilson (verified owner)

    I treated myself to the base layer as a Xmas present to me. I love it! It so comfortable and I love the look and the fit. I have lived in it most of the time since I bought it and it keeps me nice and warm no matter what I’m up to. It also washes really well. I would highly recommend this base layer whether you are active or not.
    I also bought my son one and a beanie. He loves them both. Thank you.

  18. Lindsey Knox

    It’s always a dilema for me about what to wear on days when it’s going to be a mix of hot and cold sections as I tend to get too hot wearing a normal thermal top but this got me round the Feel the Burns race without getting too hot or too cold, very impressed. The material is lovely and soft, a real pleasure to wear. Thanks Anne.

  19. Kerrie McGinn

    LOVE, LOVE, LOVE!!! I wear my baselayer all the time! I suffer from Reynaud’s and chilblains so to find something that actually keeps me warm, properly warm, is amazing! I especially love it when I’m riding, schooling the horses on the flat, over show jumps and as a base for cross-country. Looks really smart and feels super soft against my skin. Highly recommend! Thanks Anne xxx

  20. Allan Porterfield (verified owner)

    I’ve written numerous base layers over the years, running, cycling and hiking. This “Loomi” base layer is comfortable, warm and versatile.
    My go to base layer for those outdoor days.

  21. Alex

    I love my loomi base layer! It’s comfy, practical and the fit is perfect (I’m tall so have long arms)! I wear it at home and at competitions – classic navy for cross country riding. Would highly recommend!

  22. Dawn (verified owner)

    Purchased in November and worn throughout the winter for runs, hikes, yoga, cycling and for warming up after open water swims. I’ve had 2 trips up north and it was almost all I wore each time. This is my most versatile top and I now run in nothing else. I get 4-6 wears before it requires washing. I’ve been comfortable in all conditions from mild sunny days to a squally stormy day with sea spray soaking me. I cannot recommend this enough for anyone with an active lifestyle. Stylish enough to take from hill to lunch with just the addition of a scarf.

  23. Jade

    As an avid trail runner and hiker living in one of the coldest and wettest parts of England, I can honestly say this is the best base layer I have ever bought. The fabric is so soft and stretchy I can’t believe it’s merino wool!

  24. Marcus Naylor

    Just back from a 7 day bike-packing trip with 6 nights of wild camping… my loomi (long sleeve) was THE perfect base layer and favorite piece of kit. Comfortable, and performed flawlessly in the sun, rain, and wind (mostly wind!). On the odd occasion, I found myself refueling in a cafe, despite my disheveled appearance I didn’t notice others taking a wide berth, the merino fabric is great for staying fresh. Highly recommended.

    • Loomi Life Shop

      Thank you Marcus for your great feedback and for taking your Loomi to the places it was made for. Sounds like an amazing trip.

  25. Alan Hunter (verified owner)

    I wore my baselayer on a recent kayak trip round Mull and I think I gave it a hammering:

    : Baselayer was not washed and taken off and stuck up the back of a tent each night. The anti-smell aspect was very good – no real odour after 6 days.
    : it was worn for 10-11 hours each day
    : no sign of abrasion as it was used for 5-6 hours paddling each day
    : it was worn under a buoyancy aid and a spraydeck so it was always sweaty – however, it dried on me very quickly. I was pleasantly surprised as I have found Merino did not dry as quickly as other materials in the past.
    : sleeves got soaking some days from spray – this also dried quickly.
    : sleeves were always rolled up so cuffs remained stretched when sleeve was rolled down.
    Not a problem for me though.

    So all in all – very impressed. Especially as I used it for something it may not be intended for – however, I will not be the last person to do so.

  26. Stephanie

    The fit is perfect, I left it a day before trying it on. The shape is beautiful and works with my shape, and the contours over the shoulders arms etc. The neckline is also perfect and sits well. I was a little curious regarding the middle arm patch – is that re sweat? I used to be a runner and it immediately made me feel like a runner again. I am over 60 – made me feel like 40! it is a great product. Feminine. I do alot of walking as opposed to running now so look forward to wearing it then. I understand all the hard work that has gone behind your product so congrats. thank you. Stephanie

  27. David Bone (verified owner)

    Lucky enough to be highlighted to the magic of Loomilife by friends PenandJu. Bought the long sleeve as part of the mandatory kit for the Montane Winter Spine race and rather than keeping it wrapped as a spare item I quickly realised that it could be worn again and again…..and again without losing any of its powers. Wore it for the entirety of the 2023 Spine race – kept me warm in -15 degree night cold sections – breathes perfectly and as a bonus it somehow doesn’t hold on to the manly smells even on Day 5 of constant wear. A truly magnificent item and one I will be telling everyone to invest in

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Technical Innovation
Suedwolle spinning technology combines merino fibres with technical nylon filaments to achieve an even higher level of performance and durability.
Knitting Innovation
Fine gauge circular knitting technology creates the perfect finished product. Light yet durable, soft yet strong, dense yet super stretchy.