We, as runners and professional gear review writers, know well how overwhelming shopping for outdoor clothing can be. The running apparel market is oversaturated, full of products that claim to be the best, lightest, and most comfortable. Without a source you trust to help guide you through, it's easy to give up and hit the trails in your trusty old t-shirt. But that's why we're here! Our expert team of running enthusiasts spent months researching, testing, and writing about the best women's running shirts on the market today. If you already know what you're looking for, check out our Overview, where we describe the award-winning products and how we chose them. The individual reviews have all the details about why we liked and didn't like each product. If you're not exactly sure where to start and need some more information about what to look for, this is the place for you. In this article, we explain how we tested each product, what each scoring metric means, and which products to focus on depending on your personal running needs.
Running is hard enough-- why make it harder? While it may sound like a luxury, comfort is incredibly important to running success. An uncomfortable shirt can cause rubbing and chafing that can slow you down and alter your form for the worse. A shirt may seem comfortable when you first put it in, but after hours of strenuous use, you're more likely to notice small details that irritate you. We spent weeks wearing these shirts so we could really get to know them, and we had our friends and colleagues try them too to help us find a consensus. During our testing period, we found a few major qualities that greatly affected comfort.Fabric
For these shirts, we found a few different materials: cotton, polyester, elastane, and even a bit of fleece. Most of the shirts were fully polyester, but some were a blend of these fabrics. Despite their similar constructions, each one has a different feel, and your personal preference will be important here. We strongly suggest trying on each shirt first, especially if you're considering a fabric that's new to you. That being said, there are some things you might want to know about each material before digging in.Cotton
If you've never heard the expression "cotton kills," you might not know that any cotton garment is a questionable choice for the backcountry. Because of its long drying time and inability to keep us warm when wet, we generally do not promote wearing cotton in the outdoors, especially in cool or windy weather. Only two shirts in this review had cotton as part of their make-up, and both of them were still mostly polyester. The Nike Tailwind, for example, is 85% polyester and 15% cotton. The cotton helped add to its super-soft feeling, and we found no difference in its drying times because of it. If shorter runs are your jam, or if you love the super soft feeling of cotton, this could be an excellent option.
Nowadays, when we think of activewear, we think of polyester. This synthetic material is known for being breathable, quick to dry, and reasonably comfortable, but it's also known for sometimes holding odors. We didn't notice any odor buildup in any of the shirts we tested, but you may want to avoid this material if that's a high priority for you. Of the shirts, we tested, the Patagonia Airchaser, The North Face Reaxion Amp, and Arc'teryx Motus were fully polyester. The Marmot Aero is 90% polyester with just 10% of elastane jersey. In our winter models, the Under Armour ColdGear Reactor is 86% polyester and 14% elastane. The Brooks Notch Thermal is 90% polyester, but the other 10% is fleece, which we'll get to soon.Fleece
Fleece in a running shirt? We were surprised when we first laid hands on the Brooks Notch Thermal and found its ultra-cozy interior. We knew the shirt would be warm, which it definitely was, but how would it breathe? Since this top's fleece is arranged in small stripes with gaps in between, Brooks nailed it with the balance of warmth to breathability. It doesn't dry particularly quickly, but we do think this is an interesting choice if your winter runs take you through some pretty cold temperatures.
There are two factors concerning seams that affect overall shirt comfort, but because we didn't notice any seam-related discomfort during our testing, we didn't put as much emphasis on them when we were scoring. However, because we're obsessed with being thorough, we do want to spend a bit of time explaining what those factors are.Seam Location
One of the biggest struggles we're looking to avoid with seams is chafing, and the most prominent way seams cause chafing is with their location. When seams are located directly on top of the shoulder, they could more easily rub under the weight of a pack or vest. We prefer to have the seams located further down the sleeve or shoulder to alleviate this worry. Most of the shirts we tested did this, except for the Marmot Aero and Brooks Distance, both of which missed the message.Seam Type
There are three main types of seams that we noticed in this review: taped, flatlock, and overlock. The Airchaser was the only shirt in this review with taped seams. While they're easily the most comfortable, we had concerns about their durability. They're also considerably more expensive to manufacture, which may be one reason the Airchaser is a bit more expensive than some of its counterparts. The other shirts had either overlock or flatlock seams. Flatlock seams, like those on the ColdGear Reactor, Motus, and Aero have much lower profiles, reducing the risk of uncomfortable rubbing and chafing. On the other hand, the Reaxion, Brooks Distance, and Tailwind have overlock seams, which are bulky and take up three-dimensional space in often uncomfortable locations. Once again, flatlock seams are more expensive to produce than overlock ones.
Fit & Stretch
Even comfortable materials can be a pain if the shirt itself doesn't fit correctly, so we wanted to explore the different types of designs we saw in this review. If the shirt was snug, we needed it to be pretty stretchy to accommodate a wider range of motion. Some of the looser shirts we tested had less stretch but still worked because they weren't so tight. Fit is very personal, and while we did our best to reach a consensus, we still recommend trying on a shirt before purchasing to make sure it works for you.
Breathability & Drying Time
After keeping us comfortable, the most important thing we want our athletic wear to accomplish is keeping us dry. And when you're working up a sweat, whether you're deep in the backcountry or out on the track, this becomes more and more difficult to do. Our testing team identified two important traits that simultaneously work together to achieve that goal. They're closely linked, so we'll decode them here.
Breathability is the shirt's ability to breathe; right? This metric measures airflow and the shirt's ability to let moisture evaporate before it accumulates on the fabric. Shirts that are made of synthetic materials generally do this best. We also found that a looser fit helped achieve this goal.
Drying time is the measure of how quickly a shirt can dry once it's saturated with moisture. To test this, we dunked all shirts in water, wrung them out by hand, and hung them on a line to dry side-by-side. In cold weather, we want our shirts to dry as quickly as possible so that the moisture doesn't make us cold. In hot weather, that evaporation process is what helps cool us down.
Features & Versatility
Our team was on the hunt for characteristics that made each shirt perfect for running, not just as a base layer, and while we were a bit disappointed to find that not one of the models we tested had all these features, we still want to explain what they are and why we think they're important.
Sun protection: When spending hours and hours outside, nothing is as important for your long-term happiness and health than sun protection. We awarded extra points for built-in UPF rating, like that found in the Arc'teryx Motus.
Reflectivity: Having reflective markings while running at night can make a huge impact on safety. Not one of the shirts we tested had an abundant amount of reflection, but most of them had logos on the front and back to achieve this purpose.
Thumb loops: This only applies to our winter running layers, but it's an important one! Both long-sleeve shirts we tested had thumb loops, but the Notch's were considerably more comfortable.
Funnel neck: Once again, both of our long-sleeve shirts featured this high neckline, and for good reason! Both were effective at keeping in some extra warmth and protecting us from the elements, but the Reactor's two-layer collar was innovative.
After looking at what made a shirt running-specific, we also wanted to know what made it more versatile. Any time we invest money in a product, we want to get the most out of it. For any of these running shirts to also work as a more well-rounded baselayer, we looked at the features above plus a nice fit and great range of motion. While the Airchaser makes an excellent running shirt, its less-stretchy sleeves and torso make it challenging to use for other activities. The Aero, on the other hand, has excellent stretch and fit for any activity. Similarly, both of our winter layers, the Reactor and the Notch, would be great additions for any cold-weather activity.
Whether you're hiking, biking, climbing, skiing, or yes, running, most of the shirts in this review will do the trick. All are sufficient at managing sweat and keeping you comfortable, but some are better than others. If you're looking for a more versatile base layer, pay extra attention to the "Features & Versatility" section of each individual review. If running in the heat is your thing, the "Breathability" and "Drying Time" metrics will be more important. We urge you to think about your activities and what your ideal shirt looks like, and then use the information above to critique each shirt before you purchase. Happy shopping!