Isis Wool Zip-Neck Turtle

Isis’s new wool baselayers—available in a zip-neck turtle, v-neck top, and tights—offer the natural benefits of wool (temperature-regulating even when wet, odor-resistant, renewable source) in a lightweight, stretchy, flattering fit. The baselayers are made from an 80-percent merino wool and 20-percent nylon (for stretch) blend designed to be worn next to the skin. They have a feminine fit with an attractive swirl pattern that adds some interest to otherwise basic long underwear.

Since Isis’s focus is on performance outdoor clothing for women, the baselayers’ fit is contoured and stretchy, but never tight or constricting, even for women with curves. The baselayers fit best against the skin where they have maximum wicking and insulating ability and move well with your body. They also are one of the most flattering baselayers I’ve worn. I found myself looking for reasons to keep the zip-neck turtle on while backpacking in summer, even into mid-day. Luckily wool is a great temperature regulator.

They don’t just look good though.

I’ve been using the Isis wool zip-neck top and tights for more than four months now and have been pleased with their fit, construction, and insulating properties.

Isis classifies its wool baselayers as midweight, but the wool layers are lighter-weight compared to many synthetic midweight layers and have a slightly open weave that allows them to breathe. Yet they always seem to insulate as much as necessary. Because wool resists heat loss, even when wet, and helps the body maintain its optimal temperature, wool layers can keep you warm when it’s cool and cool when it’s warm. Since wool regulates your temperature to a wider degree, wool baselayers can be more versatile than synthetics.

I’ve used the Isis wool baselayers for summer hiking and backpacking in Maine and sleeping in a lean-to in the fall in temps down into the 40s. I’m sure they could comfortably go lower than that. They always seemed to provide the right amount of insulation and cooling.

While I haven’t had the chance to use them in winter yet, these baselayers have year-round applications. I anticipate using them for snowshoeing, winter day hikes, and cross-country skiing. I’d need something warmer for winter camping and backpacking though. However, they are a great option for cool weather backpacking when they can do double-duty at day and night or as an extra layer for cool summer nights.

You can’t talk about wool without mentioning the benefit of natural odor control. Unlike synthetics (which for some of us get and stay stinky after just a few hours of exertion) merino wool’s fibers don’t hold onto sweat or therefore the odor-producing bacteria in it. So you can wear wool layers longer before needing to wash them, without offending your tent mate or hiking partner. For me, one run or hike can stink up synthetic clothing fast, but I never noticed any smells from the Isis layers, even after several days of wear.

Of course, you’ll still need to wash and dry them at home. The Isis superwash merino layers are easily machine washable (cold water, gentle cycle) and dryable (low temps). I had little to no shrinkage or wear from washing and drying the layers I tested, even when I forgot about the gentle cycle recommendation. I’ll be keeping an eye on them for any signs of long-term wear though.

Those with very sensitive skin will want to test wool layers out against their own skin before committing to it as a baselayer. The wool in Isis’s baselayers is 18 microns in diameter, far thinner than a human hair, and feels pretty soft. My sensitive skin initially noticed a faint itch near my collarbone with the Isis zip-neck turtle (though not the tights), but it wasn’t enough to stop me from using them and usually was forgotten once I got moving.

One caveat, while wool is widely considered more sustainable than synthetics for its natural, renewable fibers, for the most environmentally-responsible wool clothing you might consider chlorine-free (ex. Patagonia) or organic options. Other considerations include the grazing and processing practices of a company’s wool sources and the product’s carbon footprint, all factors that many outdoor companies are starting to make more transparent for consumers, though Isis does not publish this information.

Wool baselayers tend to be more expensive than synthetic options (Isis’s are priced comparably), but they are an excellent choice for anyone looking for a long-lasting, durable baselayer with natural odor control, a range of temperature regulation, and renewable fibers. The Isis wool baselayers are a good option for outdoor women looking for the benefits and performance of wool in a feminine, flattering fit.