Smartwool Merino 150 Base Layer Bottoms - Women's Review
Compare prices at 3 resellers Pros: Lightweight, excellent wicking power, durable fabrics
Cons: Very tight and unforgiving fit, waist slides down, not warm
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Our Analysis and Test Results
The Smartwool Merino 150 stands out as a lightweight and durable merino-synthetic blend with a tight, unforgiving fit. It's constructed of 87% merino wool and 13% spandex. This product saw an update in 2020 that changed its waistband, which significantly changed its comfort and fit rating. While we'd recommend it for most activewear sports, it's important that you size up. If you're sensitive to wool, we wouldn't recommend it as we notice the fabrics are itchier than any other contender tested.
As a lightweight merino-synthetic blend, this long underwear pant offers activewear warmth in the winter that would work best with a pair of insulated pants. It contains 150 g/m² of material, making it one of the lightest options tested. The fabric weave is surprisingly tight, so while it is thin, it still provides some protection when worn on its own for cutting wind and insulating. If running, cross-country skiing, or uphill hiking is on your agenda, this pant is a great one to choose. Not because it's super warm, but because it'll breathe and wick exceptionally well to keep you dry. If you are at the resort, however, this isn't the option that we'd recommend as it doesn't insulate well during long cold periods of sitting around. For use throughout the seasons in cool weather or while exercising, it does provide all the warmth you need.
This layer has excellent breathability because the fabric is so thin. While it insulates, it is able to easily move moisture away from the skin. The weave of the fabric is fairly tight, unlike other heavier Merino wool options without a synthetic component. As a result, the thin fabrics make up for the tight weave, earning it a similar score in breathability as other options that are supposedly warmer and thicker. This is a great choice for aerobic activities in cold weather or to wear in warmer climates.
Comfort and Fit
This pant used to be a favorite for its excellent performance and comfortable fit. However, the newest iteration has changed the fit completely, even though the material specs seem to the same. It feels incredibly tight and rigid without much give or stretch. We ordered a size medium, tried it on, and immediately sent it back, thinking that we had received a lemon. However, when we got another version in the mail, we had the same issue.
Our tester who fits a medium in all the pants in this review could hardly get into this pant, wiggling and stretching the fabrics to the max. Thinking that we'd eaten a little too much candy this Halloween, we handed it off to other women that normally fit a size medium, and got similar feedback.
Smaller friends who fit a size small said the medium felt good for them, but most still didn't like the itchy feel of the fabrics and the rigidity of the new waistband. There are many other lighter-weight options that have a fit with more versatility that doesn't stretch out.
All of our testers agree that this isn't one we'd buy because of this issue. However, of the contenders, it's the one that won't stretch out even after wear for several hours. If you do buy this model, be sure to size up if you need a little extra stretch around the waist and hips.
With the integration of synthetic fibers to uphold the shape of the fabrics, this piece proves to be durable. After wearing it on its own while hiking and running, we see next to no wear and tear so far. There's no pilling to speak of, and the fabric hasn't stretched out or deformed. While the fit is rigid, it has its upsides. Of the merino wool options out there, this one surpasses others in this metric, earning it top marks.
If the fit works for you, this is a great value option with excellent durability that we've seen in our testing. As a merino-synthetic blend, the fibers are hard as nails and typically do a great job when it comes to longevity, assuming the pant isn't completely abused. While it's not the highest value option out there, it's still a lighter base layer that has incredibly wicking and breathing power. If that's what you seek, be sure to size up to enjoy it while playing in the great outdoors.
The Smartwool Merino 150 is a lightweight merino-synthetic base layer that offers superior breathability and wicking power. It's surprisingly warm for its thin fabrics and is best used for aerobic activities in cold weather. Unfortunately, the waistband is tight with an unforgiving fit. If you buy it, be sure to size up one full size for a little extra stretch, unless you prefer skintight performance.
— Amber King