Is it really comfortable even in summer? Putting joha's wool-blend inner wear to the test.

Wool in summer might seem like an unlikely pairing—wouldn't you just end up sweating? But wool is actually an excellent material that adjusts its insulating and moisture-wicking properties according to the season and your body temperature, helping you maintain just the right temperature at all times. This quality has earned it the nickname "natural air conditioning," keeping you warm in winter and comfortably cool in summer. You may have heard about wool's high functionality, but to answer the question "Is it really comfortable even in summer?", we decided to ask a staff member who deliberately purchased joha's wool inner wear at this time of year for her honest thoughts.

Wool-blend inner wear for summer, too

Some people avoid wool because they find it scratchy, but that itchy sensation isn't inherent to the material itself. It comes from the fact that wool with thicker fibers touching the skin creates a prickling sensation. The joha inner wear we're introducing today uses the finest merino wool, measuring just 18 to 19 microns (0.018–0.019mm), so it has almost none of that "scratchy" feeling people associate with wool. Generally speaking, wool is said to feel itchy once it exceeds 30 microns in thickness, so you can see just how gentle joha's wool inner wear is on the skin. 

Looking closely, you can see it's knitted with extremely fine wool

Originally, joha was founded in Denmark in 1963 as a brand of underwear for babies and children. The company believed that wool was better suited than acrylic blends or cotton for protecting children—who can't yet regulate their own body temperature well—from the cold, and this led to the development of the first children's wool underwear. joha's wool is produced without chemical treatments and holds the rare EU Ecolabel certification, so it can be worn with peace of mind not just by babies but by adults as well.

Wool also has antibacterial and immune-supporting properties, helping to suppress the bacteria that cause odor. Because it helps keep skin clean, it's especially well-suited to the season ahead, when we tend to sweat more. On the other hand, dry skin in autumn and winter is more sensitive and prone to irritation from outside stimuli, and damage to the skin's protective oil layer is said to cause rough skin. Research has even shown that wearing wool underwear can help skin recover from this kind of seasonal roughness.

Still, even knowing all this, what really matters is hearing from actual users. Rather than take our word for it, we spoke with a staff member who recently started wearing this season's new item.

Asking a wool inner wear devotee: "Is it really comfortable?"

Today's favorite item: Wool Silk Short Sleeve (Camel)

She purchased this item about two weeks ago, but it turns out she'd had her eye on joha's products for a while before that.

Staff M:
Actually, I knew that joha could be worn not just in autumn and winter but in summer too, though I hadn't gotten a piece for myself yet. I figured I'd probably end up buying it in the autumn or winter. But recently, I heard from someone who wears joha inner wear during sports activities, and it made me think that this coming season might actually be the best time to really experience how good joha's wool products are.

The person I spoke with used to compete in a motorsport, and would wear joha's 100% merino wool inner wear during races. Even after sweating a lot, their skin stayed dry and comfortable—that's why they chose it. I wanted to try for myself the quality that someone doing such intense sports had chosen, especially now in summer when sweat is such a concern. As a beginner to summer wool inner wear, I went with the silk-blend [Wool Silk Short Sleeve], deliberately choosing a style that covers the underarms, where I tend to sweat the most.

Doesn't the heat make you sweat?

Of course, when it's hot, you sweat the same as with any inner wear. But I was surprised that even when the fabric gets damp from sweat, it dries after a little while. I was curious about the underarm area especially, but it doesn't stay damp for long either—it's genuinely comfortable to wear.

I really understood what people mean when they say your skin stays dry even when the fabric is damp. I think this will end up being useful year-round—during the rainy season and in summer alike.

What about the itchiness?

I was surprised that it didn't bother me at all. Even touching the fabric, since it's blended with silk, it feels so smooth you'd hardly believe it's wool. If you touched it without knowing what it was made of, you probably wouldn't guess it was wool inner wear (laughs). For anyone new to wool inner wear, I'd definitely recommend the silk-blend Wool Silk series.

Compared to inner wear made of other materials

I think the biggest difference is that you don't get that lingering, damp feeling from sweat. When you sweat, your body gets damp and can end up losing heat and feeling chilled—but with joha inner wear, there's a sense of reassurance that you'll stay comfortable no matter what. This is especially true in summer, when air conditioning creates a big temperature gap between indoors and outdoors, and sometimes overly strong air conditioning can leave you feeling cold. joha inner wear doesn't pull heat away from your skin, so it keeps you at just the right temperature, which is really convenient. I also have inner wear made of cotton and synthetic fibers, but I think this wool inner wear is going to become one of my go-to favorites too—I'm already looking forward to it.

A new color joins a popular item

This time, ZUTTO has added a new addition to the lineup: 【Wool Silk Short Sleeve (Camel)】A soft camel color has now joined the wool-silk camisole and merino wool tank top, along with the wool-silk shorts—items that are already popular year-round among our women's inner wear.

From left: Wool-Silk Camisole (Camel), Wool-Silk Shorts (Camel)

The Merino Wool Tank Top (Camel) is a silk blend

Both the camisole and the tank top cover you securely from the chest all the way down to the stomach, making them a piece we'd especially recommend for anyone who feels the cold easily, such as those who struggle with summer air conditioning. The wool-silk shorts, which reliably protect against chill around the hips, will also come in handy year-round, from now through autumn and winter.

All of the camel-colored items are made from a blended material with a ratio of 15% silk and 85% merino wool. While the previously available Merino Wool Tank Top in white and light gray is 100% merino wool, this new camel arrival is blended with silk, making it a great choice for those trying wool inner wear for the first time.

Left: Wool-Silk Camisole (Navy), a silk blend, Right: Merino Wool Tank Top (Merino Wool Light Gray), 100% merino wool

Silk blend versus 100% wool. When we actually compared the feel of each fabric, the silk-blend fabric had an incredibly smooth texture—so smooth that it's surprising to remember it's wool inner wear at all. On the other hand, the 100% merino wool fabric is somewhat less smooth than the silk blend, but has a gentle touch almost like cotton. Even wearing it, you won't feel any warmth-related discomfort. It's an inner wear piece we'd recommend to anyone who struggles with summer air conditioning.

The "comfort" we want dads to experience

Father's Day, the June event. As a token of everyday gratitude, why not give dad—someone who probably doesn't spend much time choosing his inner wear—something gentle on the skin? Whether as inner wear under a suit on weekdays, or under casual clothes for weekend outings, inner wear is something worn directly against the skin every day, so it's worth choosing something truly comfortable to wear.

Men's Merino Wool Tank Top

Men's Merino Wool T-Shirt

For those who prioritize ease of movement, the tank top is a good choice; for those who often pair inner wear with thin shirts, the T-shirt works well. Both have a wide neckline, so from spring into early summer they work nicely as inner wear under shirts or cut-and-sewn tops, and from autumn into winter, even layered under a long-sleeve sweater, they provide just the right fit without feeling overly bulky.

For baby gifts, a matching set for mom and baby

Mom & Baby Matching Set

This time, we've also put together a ZUTTO original combination: a set that lets mom and baby enjoy matching inner wear in comfort together. A tank top for mom, and a body suit for baby. The material used is a blend of 85% merino wool and 15% silk. This is a set made possible precisely because joha is a brand that both babies and adults can wear with peace of mind.

In its home country, the tank top is from the kids' series, sized at 150cm. While there is some individual variation, it's a size that Japanese women up to about 160cm tall can wear without any problem. The body suit comes in size 80cm, intended for babies around 1 to 2 years old.

Available in two colors, navy and gray. We ship the set in matching colors

With two easy-to-choose colors, navy and gray, this is a set we'd recommend both as a baby gift and for your own use.

Baby Gift Lace 2-Piece Set, Off-White

This is a gift set we've prepared for babies, consisting of a wear and a hat. This material is also a silk blend, with the smooth merino wool gently wrapping around baby. The off-white lace detailing is adorable, and it beautifully highlights the small, pure presence of a baby.

This one also comes in size 80cm, intended for babies around 1 to 2 years old. On hot days, it can be worn on its own, or layered under other clothing so that only the lace part of the collar peeks out—both looks are equally charming.

The rainy season is approaching, bringing with it concerns about humidity. And once the rainy season ends, full-blown summer arrives, along with the difference between outdoor and indoor temperatures. It may be precisely in this humid Japanese summer that joha's wool inner wear proves to be just right.

Click here for the joha brand page