Ultralight active fleece is all the rage in the hiking and backpacking community these days. But, just like any other piece of gear (or material used in it), it has upsides and downsides. What’s more, with several breathable, ultralight active fleece materials available, choosing one can seem like its own challenge.
Luckily, you’ve got the experts at GearJunkie to do the work for you. We’ve tested tons of fleece materials and many ultralight fleece products. We’ve talked with experts, spent time with the brands, and delved into the science surrounding this fabric. We love ultralight fleece — but we also know that not all of it is created equal.
Here are four of the main types of ultralight fleece on the market today. We’ll discuss strengths and weaknesses, and what products feature the best in ultralight fleece. This guide isn’t a comprehensive list, but if you’re shopping for an ultralight fleece midlayer, it’s a good place to start.
Check out more fleece jackets on GearJunkie’s guide to the Best Fleece Jackets.
What Is Ultralight Fleece?
If you’re not familiar with ultralight, breathable fleece, it’s important to understand what it is, and just as importantly, what it isn’t.
This active insulation is designed for high-output, start-stop activities like hiking, trail running, backpacking, and Nordic skiing in cool to cold weather. Because the fabric is so breathable, it’s often see-through.
Moisture wicks very efficiently through it, and it breathes exceptionally well. As such, it’s ideal for maintaining body temperature while in active motion, without constantly removing layers.
It’s also highly packable, compressible, and lightweight. Long or fluffy fibers between loose fabric knits trap heat similarly to wool fibers when layered under a windproof layer. So, when weight matters, ultralight fleece gear generally offers an impressive warmth-to-weight ratio.
What this type of fleece is not: A standalone insulating layer. Unlike traditional fleece, it won’t keep you cozy on its own when you’re sitting around a campfire.
You almost have to layer it under something else. Wind will bite through this type of fleece. And while it retains its insulating properties when wet, it gets wet pretty easily if you’re caught in precipitation. It is not “weatherproof” by any stretch of the definition.
It’s also delicate. So if bushwhacking is on your regular lineup of activities or you tend to be rough on your clothing, you may want to consider alternative active layers and/or learn to hand-sew.
Here are four of the top ultralight fleece options, and my impressions from testing each one.
Polartec Alpha Direct (LEVE Outdoors Hoody)
“Firsts” often become the standard that all later versions are compared with. It’s no different when it comes to ultralight fleece. Polartec invented the concept in 1991, and it has since become a hit among ultralight backpackers. It’s so light that if you hold it up to a light source, you can clearly see through it.
At 50-90 grams per square meter, Polartec Alpha Direct weighs less than almost any ultralight fleece fabric, and it’s versatile. Because it’s been around the longest, Polartec ultralight fleece is also the most widely available.
I tested an Alpha 90gsm Hoody ($105) from Leve Outdoors while hiking in the mountains in the fall and winter. It weighs 4 ounces.
Performance
The fabric is hydrophobic and stupendously breathable. If I managed to sweat in it, I’d be bone dry in minutes thanks to the large surface area of each individual fiber. It wicks moisture very effectively.
Alpha Direct doesn’t have much stretch, but the wide-open mesh construction leaves plenty of room for freedom of motion. It’s also surprisingly insulating when paired with a windproof layer.
Durability
The material is very delicate and can be torn by a wayward branch or zipper. However, individual threads didn’t snag as easily as some other ultralight fleece fabrics.
Sustainability
The material composition of Alpha Direct can vary, but the LEVE Outdoors hoody I tested is made of 78% recycled polyester and 22% virgin polyester.
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Polartec Power Dry Mesh (Houdini Pace Flow Half Zip)
Polartec’s Power Dry Mesh is only available in options from limited brands. Houdini is one of them. I tested the brand’s Sportswear Pace Flow Houdi and Half Zip ($180), which weighs 8.6 ounces.
This material is more of a 3D mesh than fleece. It eschews long, fuzzy fibers for a compact, smooth, open grid that looks good on its own and layers well. I was amazed when backpacking in the Tetons at its ability to insulate just by throwing a light rain jacket over it.
Performance
The material doesn’t contain elastic stretch. However, thanks to the open grid pattern, it stretches just enough to easily pull it on and off. It also sports an athletic fit and is moisture-wicking to dry fast. That makes this fleece material great for active pursuits, like hiking or running.
Durability
Of the ultralight fleece fabrics I tested, this material felt like the most durable. It has a tighter weave, which reduces the chance of snagging and gives it a more substantial handfeel.
I still managed to snag a few individual fibers from time to time if I wasn’t paying attention. But it doesn’t rip or tear as easily as some other ultralight materials.
Sustainability
Designed and crafted from mono materials, the Houdini Pace Flow is made of recycled materials and is recyclable at the end of its usable life. It’s also Bluesign-certified.
It also doesn’t shed very many microfibers. Almost all ultralight fleece fabrics shed; however, the weave used in Power Dry Mesh is designed to prevent shedding, thus reducing micro pollution.
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Teijin Octa (Sambob Hoodie)
One of the newest ultralight fabrics to hit the scene comes from Japan: Teijin Octa. It gets its name from the eight-armed structure of individual strands of hollow-fiber lofted insulation on the inside. The outside has a smooth mesh-like face.
Like Polartec Alpha Direct, Teijin Octa is available in several fabric weights. I tested the material in the Sambob Octa Hoodie ($115), which weighs just 4.6 ounces.
Unlike some other options, Teijin Octra’s fur-like, fleecy insulation is on the inside rather than the outside. That means the easier-to-snag fuzzy face is less exposed and vulnerable to catching on things. The exterior uses a smoother fabric that’s easier to layer over and collects less grime.
Performance
Octa wicks sweat like a champ. I noticed that it pulled moisture from the inside out effectively and dried out fast when I was working up a sweat. The hollow fibers also reduce weight. Octa claims that its fabric is 50% lighter than yarn that isn’t hollow.
Truly, it’s one of the lightest materials I tested. Its performance was impressive for active use. However, the handfeel isn’t quite as soft as other options.
Durability
Thanks to a smooth, more robust outer fabric, Octa is less likely to tear after a run-in with rough boulders or brushy trails. This option held up to more abuse better than other ultralight fleece fabrics.
Sustainability
Teijin is a Bluesign System Partner. Non-brushed versions like those in The North Face’s Futurefleece line reduce microfiber shedding.
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PrimaLoft Active Evolve (Backcountry Highliner PrimaLoft Air-Perm Fleece)
This recent addition to the active fleece lineup is bunny-soft and oh-so-cozy. That’s thanks in part to fluffy fiber on both the inside and outside of the Active Evolve. That made it the coziest of the bunch right out of the gate and a pleasure to don for all manner of activities in chilly temps.
I tested the Backcountry Highliner PrimaLoft Air-Perm Fleece ($100). It weighs 6.2 ounces. The fabric is stretchy, more so than any other material I tested. Which means it offered more fit flexibility and potential comfort during extreme movement or stretching activities like climbing or mountain biking.
Performance
Active Evolve is one of the heaviest ultralight fleeces I tried for this article. According to PrimaLoft, it comes in a wide range of weights from 75 to 250 grams per square meter. So, it’s still well in the ultralight range.
It’s also hydrophobic, which helps with moisture management. In the instances where I did manage to get it damp, it seemed to dry out fast.
Durability
This was possibly the least durable of the ultralight fabrics I tested. It snagged in multiple spots the first time I wore it. It seems very easy to tear, and I would not wear it without an outer layer to protect it.
Sustainability
This material is made with 100% recycled polyester and is OEKO-TEX STANDARD 100 Certified. However, microfiber shedding was an issue. Laundering reduced the amount of microplastic fibers shed, but I was still disappointed with the amount of microplastics it contributed to the environment compared to other materials.
I’d point out that Active Evolve’s durability poses a potential sustainability issue as well. If you ruin a garment within the first few months of use, it just becomes garbage — even if it’s made from recycled materials.
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Bottom Line
Ultralight fleece is a miraculous material for outdoorists who like to push their limits. As a midlayer material, it traps heat effectively, wicks moisture efficiently, and doesn’t weigh you down on the trail. Worn under a more substantial fleece layer or a shell jacket, it boosts warmth on chilly adventures without added bulk or weight.
With several options out there, you can shop for the right ultralight fleece layer based on your needs and preferences. If you really like the soft handfeel of fuzzy Polartec Alpha Direct, check out the LEVE Outdoors Hoody I tested, or the Backcountry PrimaLoft Air-Perm Fleece Hoodie. If you are shopping for pure performance and longevity, I’d point you toward Teijin Octa or Polartec Power Dry Mesh garments.
Pick the right ultralight fleece material based on performance, durability, and sustainability, and you’ll enjoy a lighter pack and fewer breaks to adjust layers on every adventure.
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