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Madison Isoler Merino Baselayer



A cosy and warm baselayer but the sleeves could be a little longer

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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Madison's Isoler Merino zip-neck baselayer is luxuriously soft against the skin, warm and cosy – just the ticket on cool morning or evening rides or through the winter under a jacket.

A lot of thought seems to have gone into the design and detail, with various panels shaped to ensure a body-hugging fit and all the seams flatlock-stitched to prevent skin irritation. This helps justify its £50 price tag, which is about mid-price compared to similar merino baselayers.

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The Isoler is made from 100 per cent merino wool, a midweight 190gsm that strikes a balance between warmth and wicking ability. Although Madison boasts 'unrivalled moisture absorption' – and it has three external 'M:TEC Wicking' labels – I found it performed just the same as my other merino baselayers, not surprisingly.

Madison Isoler Merino Baselayer - merino logo.jpg

During moderate exercise the back got sweaty but, thanks to wool's thermal properties, it stays warm even when wet. Another advantage of wool over manmade materials is its anti-pong attribute, so a baselayer like this is ideal to wear on a multi-day touring trip, for example, as it won't stink to high heaven.

> Check out our guide to cycling baselayers

The fit of the Isoler is good on the whole, the natural fibres stretching and moving with your body. I like the half-zip neck (with zip garage so you don't have a zip pull against your skin) – I use it frequently to aid temperature regulation. The collar fits snugly but I'd prefer it to be a little taller.

Madison Isoler Merino Baselayer - collar.jpg

My main niggle with the Isoler, though, is the length of the sleeves. Off the bike they're fine, but in the riding position the cuffs sit above my wrist bones, so there's exposed skin between them and my gloves. Another two inches would be perfect. Ideally, I'd like the body to be longer as well; there is a slight drop hem at the rear but when it's cold I prefer a nice long back to cover my hips.

Madison Isoler Merino Baselayer - cuff.jpg

Thoughtful design details include raglan sleeves, which means no shoulder seams to potentially rub under a pack, and a lozenge-shaped panel underarm, so again, no seam chafing issues there. The side seams run assymetrically back towards the hips, but I'm not sure what purpose this serves. Lastly, there's no annoying label to cut out, the care instructions instead being printed inside the top.

Madison Isoler Merino Baselayer - side seams.jpg

Madison lists reflective detailing as a feature, but I couldn't find any – the M:TEC labels are just white.

The Isoler comes in black as well as this Aqua Blue, and for a fiver less you can get the crew-neck version.


A cosy and warm baselayer but the sleeves could be a little longer test report

Make and model: Madison Isoler Merino Baselayer

Size tested: 10

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Madison says: "An ideal first layer, the Isoler Merino baselayer provides unrivalled moisture absorption."

Tell us some more about the technical aspects of the product?

100% Merino 190gsm wool

Flat-lock stitching

High zip-neck collar

Machine washable

Limited lifetime warranty

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:

Beware Velcro! After several washes, the fabric looks a little fuzzy in places.

Rate the product for fit:

Body and sleeves not quite long enough for my liking.

Rate the product for sizing:

I'm a 10 in Madison shorts but a 12 in tops and jackets.

Rate the product for weight:
Rate the product for comfort:
Rate the product for value:

You can find very similar options both cheaper, eg £25 from Decathlon, and pricier, eg £70 Icebreaker.

How easy is the product to care for? How did it respond to being washed?

Easy: machine wash 30.

Tell us how the product performed overall when used for its designed purpose

It did its job of keeping your body warm and wicked as well as most merino baselayers. However, it would feel cosier if the body and sleeves were longer.

Tell us what you particularly liked about the product

The super-soft feel of the wool against the skin.

Tell us what you particularly disliked about the product

The too-short sleeves.

Did you enjoy using the product? Yes

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Use this box to explain your score

It's a well made, comfortable baselayer, but if it was more generous in length the Isoler would have scored 8.

Overall rating: 7/10

About the tester

Age: 44  Height: 170cm  Weight: 64kg

I usually ride: Marin Point Reyes 29er  My best bike is: Giant Anthem X1

I've been riding for: 10-20 years  I ride: Most days  I would class myself as: Experienced

I regularly do the following types of riding: commuting, touring, club rides, mountain biking, audax

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