The Arc'teryx Rho LT Zip Neck is our favorite synthetic base layer. As an ultra-versatile and cozy top, we found ourselves comfortable and happy on outdoor adventures ranging from campfire singing to hiking peaks above 14,000 feet. The fleece interior sits close to the skin generating warmth and thermoregulating over a wide range of temperatures. It's easy to layer with great features, like the zip-neck, a handy stash pocket on the sleeve, and a kangaroo pouch to keep those digits warm and toasty. While this is a heavier base layer and not suited for high-intensity pursuits in warmer climates, it takes home a prize because of its incredible durability, performance, and fantastic versatility. Take it with you on your next big adventure, whatever that might be.Editor's Note: This review was updated on November 15, 2022, after retesting the most current version of this base layer.
Cons: Expensive, not super breathable, boxy updated fit
Compare to Similar Products
Arc'teryx Rho LT Zip Neck - Women's
|Price||$130 List||$145 List|
$145.00 at Amazon
$109.00 at REI
|$75 List||$55 List|
Check Price at REI
|Pros||Cozy fleece interior, easy to layer, warm, versatile, stash pocket, kangaroo pouch, high quality||Breathable, excellent thermoregulation, extra warmth with hood, easy to layer||Superior breathability, excellent warmth, long zip neck for venting, durable construction, comfortable micro grid fleece interior||Affordable, thumb loops, long cut, easy to layer over top, soft and durable fabric||Affordable, thumb loops, soft fabric, great fit, durable|
|Cons||Expensive, not super breathable, boxy updated fit||Expensive, takes a few washes to increase next-to-skin comfort||Fabric holds odor, thumb loops lack quality, not a thermal weight despite name||Material is not midweight||Tightly woven fabric doesn't breathe very well, smelly|
|Bottom Line||This high performance synthetic layer is ready for pretty much any adventure you dream up||A top-notch lightweight performer featuring exceptional thermoregulation and breathability with an innovative Merino wool technology that gets softer with every use||Outstanding warmth and breathability make this layer one of our favorites for high output mountain activities||This affordable base layer features ultra fine Merino wool fibers that are super comfortable next to your skin, effectively wick away moisture, and remain odor-free||This durable base layer features a soft and stretchy fabric and a slim fit for a variety of activities, all for an affordable price|
|Rating Categories||Arc'teryx Rho LT Zi...||Black Diamond Solut...||Patagonia Capilene...||Ridge Merino Aspect...||REI Co-op Midweight...|
|Comfort and Fit (20%)|
|Layering Ability (20%)|
|Specs||Arc'teryx Rho LT Zi...||Black Diamond Solut...||Patagonia Capilene...||Ridge Merino Aspect...||REI Co-op Midweight...|
|Measured Weight||7.5 oz||6.6 oz||6.1 oz||6.0 oz||7.5 oz|
|Material||Torrent 190 (84% polyester, 16% elastane)||78% Merino wool, 22% polyester||92% recycled polyester, 8% spandex||84% Merino wool, 16% nylon||92% polyester, 8% spandex|
|Avaliable Cuts||1/4 zip, crew, hoody||Crew, 1/4 zip neck/hoody||Zip neck||Crew, 1/4 zip||Crew, 1/2 zip neck|
|Odor Control Fabric||Polygiene||Naturally odor resistant||Polygiene permanent odor control||Naturally odor resistant||None|
|UPF (sun protection)||No||No||No||50+||50+|
|Fit||Trim fit||Runs small||Regular fit||Slim||Fitted, true to size|
Our Analysis and Test Results
The Arc'teryx Rho LT Zip features a deep half-zip collar with a convenient stash pocket on the left sleeve and a kangaroo pocket for keeping those hands warm and cozy when the temperatures drop. This synthetic layer effectively regulates your core body temperature, but, unfortunately, it does not breathe as well as other more porous layers due to the Polartec fleece construction. Like most synthetics, the Rho LT does retain a bit of body odor though the Polygiene treatment kept the odor at bay for most of our testing period. This is one of the warmest and most durable layers we tested, making it one of our favorite synthetic base layers for cold-weather adventures.
From the tops of mountains to the canyons of the desert, this roasty, toasty midweight base layer will keep you warm in those frigid conditions. Built with 84% polyester and 16% elastane, the Rho LT provides just the right amount of warmth, thanks to a shorter hip length and trim fit that locks in body heat. The fleece-lined interior and zip-up collar will keep you warm during those super cold weather days. This is a perfect base layer when worn below your down jackets for backcountry or resort skiing, as well as on its own for those shoulder season days on the trail.
While the face fabric of the Rho LT isn't windproof by any means, it does help cut the wind to a certain degree. As a result, this is a great stand-alone piece that will regulate body temperature on the move but also keep you warm while standing still. This is the warmest synthetic option we tested and one of the warmest base layers overall. Feel free to wear it under a jacket or mid-layer during the coldest days of the year or as a stand-alone piece when rock climbing or trail running during the cooler days in the spring and fall.
While warmth is a strong suit for this contender, breathability is not in comparison to other options. The fabric is relatively breathable (it is a base layer, after all), but it doesn't perform as well as other layers in this review. That said, the fleece-lined interior provides additional comfort and does an excellent job of wicking away moisture from the skin. The zipper allows for versatility, providing an option to trap or release body heat generated during activity as needed. When running, skiing, rafting, and generally playing in this top, we noticed that moisture easily transfers from the skin to the outside of the fabric.
The wicking power of the Rho LT is great, though the fabric itself is tightly woven, and the shirt doesn't have any additional venting other than the quarter zip. Options with a looser weave simply perform better in this metric. However, the Rho does cut the wind, which ultimately contributes to overall warmth, so it's just a matter of determining which aspect is more important to you. The Rho has been our favorite for running in cold weather and skiing when it's nippy outside. It functions well on its own or in a layered system.
Comfort and Fit
Do you love the soft, luxurious feeling of microfleece against your skin? We sure do! The majority of our testers agreed that wearing the Rho LT Zip is like being wrapped in a soft fleece blanket all day long. The elastane in the fabric makes the fit tight but not claustrophobic, while the fleece lining is super comfortable. Though we've been psyched on the fit of previous iterations of this layer, we must admit that the latest update features a shorter hip length and a trimer fit meant to keep warmth close to the body, and our lead tester decided to go up a size. The arm lengths are perfect, but the kangaroo pocket contributes to a somewhat boxy fit.
The Rho LT is constructed with flatlock seams that don't itch or chafe the skin while on the move, and the thicker fleece-lined material adds a touch of comfort. In addition, there are a few stand-out features, like a handy pocket on the left sleeve that's perfect for stashing a key, credit card, or energy gels. Our testers love the overall stretchy fleece-lined fabric and the flatlock and merrow stitch seams, but we have to admit the boxier fit of the updated version isn't as flattering as previous iterations. That said, this layer will offer top-notch performance during the worst weather conditions.
Featuring a slippery face fabric and a stretchy construction, this top is super easy to layer. Its face fabric is silky smooth and doesn't generate static cling like some of the Merino wool contenders featured in this review.
In addition to being easy to layer a down vest or jacket over the top, it's also simple to add a tank top or tech tee underneath the Rho LT. The new boxy fit with the kangaroo pocket gives this layer more room in the waist, but the arms are more fitted and may require some adjustment if you want to add another lightweight base layer with sleeves underneath. Overall, the smooth and stretchy fabric makes this top rather easy to wear alone or within a layering system.
The Rho LT Zip is incredibly durable. With a prior version, even after six years of (ab)use, one of our testers did not notice any issues with longevity. Time will tell if the updated version is as strong. Regarding odor, like most synthetic shirts, we noticed that the "odor-resistant" Polygiene treatment did a pretty good job for a bit, but its effectiveness started to wan after a couple of months.
In general, Arc'teryx is renowned for their fantastic construction, and the high-quality craftsmanship is obvious on the Rho LT. The reinforced seams and stitching set this layer apart from other brands. While the initial investment is higher than most, we do not think you will be disappointed by the performance and durability you receive in return.
Should You Buy the Arc'teryx Rho LT Zip Neck?
While the price tag for the *Rho LT Zip is on the steep side, we think it's fair for what you get. This base layer offers many performance attributes and incredible durability that you wouldn't be able to find in most other layers available today. Given that a previous iteration of this top lasted us over six years, we can attest to the fact that despite the high price, the value and quality won't disappoint. This layer is best for those seeking maximum warmth during the colder months in exchange for their initial investment.
What Other Base Layers Should You Consider?
If you're looking for a more affordable and breathable synthetic base layer that doesn't sacrifice high performance, check out the Patagonia Capilene Thermal Weight Zip-Neck. If you want warmth and versatility without the lingering odor, look to our favorite Merino option, the Black Diamond Solution 150 Merino Quarter Zip.
— Trish Matheny
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