joha, a pioneer of wool inner wear. Revisiting the appeal of an inner layer you'll want to buy again every year

Year after year, we've been enthusiastically sharing "the goodness of wool inner wear." It was joha, an inner wear brand we've carried for many years, that first made ZUTTO's buyers and product planners aware of just how good wool can be.

joha was born in Denmark, a Nordic country known for its harsh cold. While the brand now offers many inner wear items for adults, it originally started with babywear. Believing that wool suits babies and children—who cannot regulate their own body temperature well—better than acrylic blends or cotton, joha developed the very first wool undergarments made for children.

Many people have already discovered just how good wool inner wear feels

Having introduced joha for so many years, what continually surprises us is just how many repeat customers there are. Some buy the same style in a different color partway through the season, others purchase the same item at the same time every year, and still others start with a tank top as a trial, love it, and go on to try the long sleeve or leggings too.

Wool is, in a sense, a functional material—it provides insulation or lets moisture escape depending on the season and your body temperature, always working to keep you at just the right warmth. With that in mind, it can technically be worn in the depths of winter or the height of summer, but as a longtime wearer myself, I really think winter is where it truly shines. The warmth is on another level.

And there's one more thing I keep saying, and I'll say it again here (laughs): it doesn't feel unpleasant even when you sweat! Synthetic inner wear doesn't dry out, leaving that clammy, sweaty feeling, whereas wool inner wear dries quickly and doesn't leave you cold—which is a real relief.

Standard wool inner wear you can keep buying, year after year

joha is a staple item that ZUTTO has carried for over five years now. The beauty of a staple product is that once the season comes around again, you can simply buy more of something you already love. Once you find a staple item that feels just right for you, you can go through every year with peace of mind.

[100% Merino Wool Series]

Available items: tank top / long sleeve / leggings / men's

Since this is 100% wool, the main concern is probably how "itchy" it might feel. joha uses fibers of just 18-19 microns—among the finest grades of quality merino wool available. Generally speaking, wool used in high-end knitwear is 19.5 microns or finer, and people tend to start feeling itchiness with fibers of 22 microns or coarser. Those numbers alone show just how unlikely it is that joha's wool inner wear will feel itchy.

Wool's itchiness is also said to be felt more strongly on dry skin, and there is apparently research data showing that wool can actually help restore such dry skin. Beyond simply keeping you warm, it absorbs and releases sweat, so your skin always stays dry and comfortable rather than feeling unpleasant.

The long sleeve comes in both XS and S sizes.

▲Comparing the XS and S sizes of the "Merino Wool Long Sleeve"

As with all the series, the sizing (body length and sleeve length) runs a bit larger than what's typical for Japanese body types.

[85% Merino Wool, 15% Silk Series]

Available items: tank top / camisole/long sleeve / leggings/shorts

The advantage of blending in 15% silk is the smooth, moist-feeling texture it brings. No matter how fine the fibers are or how unlikely they are to itch, some people new to wool inner wear—or those who know their skin is sensitive—may still hesitate to try 100% wool. For them, we'd recommend this silk-blend version.

Silk is a natural protein fiber, made up of amino acids close to those found in our own skin, which is why it's considered good for both skin and overall health. The elegant sheen you see in the fabric comes from silk's natural beauty, and despite its delicate appearance, it's also known to be a remarkably strong, tension-resistant fiber.

Just like wool, silk also has moisture-wicking, breathable, and insulating properties, which makes the wool-and-silk combination a truly luxurious material.

Also, since the "85% Merino Wool, 15% Silk Series" is thinner than the "100% Wool Series," it's ideal as an inner layer to wear under shirts or fitted, high-gauge knitwear.

This one also comes in XS and S sizes for the long sleeve.

▲Comparing the XS and S sizes of the "Wool Silk Long Sleeve"

Even when we tried wearing and comparing them ourselves, we didn't actually notice much difference in fit. That's because the fabric has so much stretch that even someone who is 162cm tall can wear the XS size without any problem. If there's anything to consider, it would be the shoulder area and the body length. Beyond that, it really comes down to whether you prefer inner wear that fits snugly against the body or one with a bit more room.

▲For the tank top, the "camel" color is the wool-silk type.

What's the difference between the two series? A staff comparison

・Differences in feel and stitching

"When you touch them, the silk-blend one definitely feels moister, with a smooth, silky touch. The 100% wool one, on the other hand, isn't as sheer, and gives an impression of being thin yet firm.

I'd say the silk blend wins on softness against the skin, while the 100% wool wins on warmth."

"Also, while comparing the two this time, I noticed for the first time that there's a difference in the stitching between the two series. The 100% wool series uses a flat-seam finish, where the seam allowance is flattened with stitching so it doesn't bulge at the inside of the arms or under the arms. This can be seen as a consideration to reduce the discomfort and itchiness caused by the seam allowance rubbing against the skin."

▼Merino Wool 100% Series (Flat Seam)

▼Wool & Silk Series

*Depending on the item, some are made with the flat-seam finish and some aren't, but the Long Sleeve shown in the image below is not made with a flat-seam finish.

"When I checked again, I found that items made of 100% Merino wool, such as the Long Sleeve, Tank Top, and Leggings, all had this flat-seam finish (except for the Men's Tank Top). If you're bothered by the seam allowance sticking out, we recommend choosing the 100% wool option.

As for the 85% merino wool / 15% silk series, some items have the flat-seam finish and some don't, and it varies by item. For details, please check the 'Product Details' section on the catalog page."

・Size differences between the two series

Both series offer the "Long Sleeve" in XS and S sizes, so I looked into whether there's a difference in the sizing between the two series.

Here are the flat-lay measurements for the Long Sleeve in size S for each series.

	100% Wool	Silk Blend
Shoulder width	30.5	32
Body width	33.5	33
Length	63	61
Sleeve length	62	61

(Unit: cm)

Since these are cut-and-sewn (knit) materials, the flat-lay measurements can change significantly with even a slight stretch, so please take the numbers as a rough reference only. There's no major difference between the flat-lay sizes.

That said, once I actually wore them, I noticed a difference. Whether it's due to a difference in the knitting method or the material itself, the silk blend seems to stretch more. It's nice that it makes the shoulders easier to move.

To sum up,

・100% Merino wool: A firm material with high heat retention. Most items feature a flat-seam finish.

・Silk blend: Stretchy, with a smooth, silky feel against the skin. Less itchy compared to 100% wool.

Resolving Concerns for Wool Innerwear Beginners

・Won't it crackle with static electricity?

Honestly, static electricity does happen. If I wear it all day and take it off at night, there's a crackle. But I don't feel any static unless I'm actually taking it off. As for whether it's less prone to static than other innerwear, I can't really tell from experience.

・Is it okay to wash it in the washing machine?

Yes, I wash it normally in the washing machine. I put everything in a laundry net, so I do the same with my joha innerwear. I don't take any special care when washing or drying it, but I do avoid putting it in the dryer. (Since it's wool, it will shrink!)

・Doesn't it stretch out with use?

I don't feel the kind of stretching-out-from-wear-and-tear that you get with synthetic innerwear. Of course, since it's a knit made of wool, it stretches to fit your body while you're wearing it, but it doesn't end up loose and baggy once you take it off, and this hasn't changed even after repeated washing.

Also, regarding the "pilling" that's common with wool, at least with the silk-blend innerwear, I haven't seen any at all even after two seasons of wearing it regularly. Compared to when it was new, I see no difference in the fabric, and it remains in beautiful condition.

"Innerwear" is a very personal item worn against the skin, and preferences vary from person to person. But something as natural and simple as joha, with functionality you can really appreciate once you start using it, makes you want to choose it as a gift between women too. It's also a great choice for a gift during the autumn and winter season.