Synthetics are best for warmer temps, more aerobic activities, or if there is prolonged wetness (from environment or sweat). They’re also great for kids who have wool allergies. Some base layer brands understand that people of all sizes love getting outside. Some brands still have yet to get the memo. Smartwool and Patagonia have the broadest range of sizes available, including plus sizes and kids’ sizes. Do you want base layers tight or loose? Fit is also important, but it depends on your preferred outdoor activity. Tighter tops will trap more warmth, but opt for a looser cut if freedom of movement is a priority or if you’ll be wearing it for several hours. Cons: This is a premium fabric, with a premium price tag to match. Some of our testers also found it less comfy to wear than some synthetic tops. Synthetic material

We love the Patagonia Capilene Midweight and think it shines as a running base layer. It's the best synthetic base layer out there, with decades of refinement and perfection. This synthetic base layer is versatile, suitable for wearing by itself or layering under a mid-layer. While there are less expensive synthetic base layers, the quality and durability (not to mention relative eco-friendliness) of the Capilene Midweight make it the best choice for synthetic. Downside to Merino is that it is delicate and care must be taken to not damage the delicate fibers. Items can get snagged on Velcro, tree branches, hangnails, and gear. However, it is often repairable with a little needle and thread. If you’ve also been on the fence on whether quality baselayers are worth the investment then this post is for you. Below is a list of favorite baselayers for kids of all ages with input from the entire Mountain Mama Team.Smartwool has been making a version of this layer for almost three decades. Each iteration has made it better and better. On the flip side I have another child that is always complaining of being cold. Her teachers at school tell me every year that she wears her winter coat in the classroom all day long.

The Ik’splorer set and adventure oneside both have handmitts for sun and snow and are made of 100% merino wool. Unlike Ella’s wool, the feet are open on the Ik’splorer set and the baby adventure onesie. I’ll be the first to admit that I was late to jump on the baselayers for kids bandwagon. I’ve always loved and worn them as an adult, but I did not appreciate until very recently how much they truly make a difference in keeping kids warm from the inside out. Synthetic baselayers are most often made of polyester, nylon, spandex, etc. They come in a wide range of styles, price points, and technologies, like adding silver to aid in antimicrobial properties. Shred Dog is a company that cuts out the middle man and sells direct to you. Their model is designed to get parents quality gear while avoiding the retail markup.For many folks, it’s much easier to throw a base layer in the washer and dryer without having to think too hard about it. Some brands, like Smartwool, design their fabrics with this in mind. Other layers are a little more complicated in their care.

Trail runs were incorporated into our test plans to assess breathability and versatility. Though silk offers a higher warmth-to-weight ratio than other fabrics, it is less breathable than other natural fibers.The Smartwool Intraknit Thermal Merino wins top honors for its weight class thanks to its innovative seamless knitting technology that blends swaths of warm fabric with panels that add durability and ventilation — all without requiring additional seams, which saves on weight and bulk. We think this is a pretty cool innovation, and it seems to work. The slim, athletic fit excels as a base layer, allowing you to top it off with additional layers for a complete system to prepare you for the harshest of conditions. Extra long sleeves, torso, and a drop tail hem ensure that the Intraknit Thermal covers you no matter how you move. The midweight Merino wool blend fabric is a great "just right" weight to use for most cool to cold days outdoors. If it’s cold, you may intend to pile on the layers. But having a lightweight layer as your next-to-skin layer gives you more flexibility for temperature adjustment while doing something active. This allows you to keep the warmth against your body and adjust as needed. Many folks will layer a heavyweight base layer over a lightweight one for very cold aerobic sports. Another notable development is the widespread adoption of recycled synthetic materials. Companies are innovatively utilizing recycled polyester, significantly reducing fossil fuel consumption and curbing the production of new plastics. For instance, Patagonia's Capilene Midweight base layer is crafted entirely from 100% recycled polyester, exemplifying the industry's commitment to environmental responsibility. By reusing materials, outdoor brands are actively reducing their ecological footprint and contributing to a circular economy. The baby baselayers are footed which keeps feet warm too. They come in moss green, gray, navy blue and pink.

Although synthetic baselayers dry fast when wet, they do not keep you as warm when they are wet and can often leave you feeling clammy if the material doesn’t have airflow to dry. The Good Housekeeping Institute tested 29 base layers, with our panel wearing each top for at least three outdoor workouts. Teens tend to like that they are not itchy and feel like they’re a great, comfortable product at a great price point. Thumb holes prevent my hands and wrists from feeling the chill without having to layer up with running gloves (Image credit: Julia Clarke) 2. Keeping coolThin and lightweight Merino blend, 1/4 zip enhances thermal regulation, extra long sleeves and torso The teens favorite baselayers are cheap ones I got from the REI brand on clearance. TMM Team Member Rita When I talked to Ashley, one of her biggest criteria for a base layer is how it fits. While specific fits of base layers are designed for certain use case scenarios, it’s essential to choose a base layer that you feel comfortable wearing. For example, if you don’t like other people seeing you in tight-fitting clothing, an athletic slim-fit base layer is likely not going to be the best choice for you. HOW MUCH TIME ARE YOU WILLING TO INVEST IN CARING FOR YOUR BASE LAYERS? Even if your base layers are designed for the regular laundry cycle, Helly Hansen suggests that “standard laundry detergent can leave behind a film that attracts odor-causing bacteria”-something to consider if your base layers see heavy use. We tested our base layers running, hiking, climbing, working from home, running errands, and lounging on the couch. We tested for 6 months in various conditions and climates-from snowy mountains to desert and from late spring snow to fall night runs.