I Tested the Ibex Mammoth Full Zip Hoodie in Patagonia's 'Wind Capital.' The Hoodie Prevailed.

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Summary of our Ibex Mammoth Hoodie test:

Pros:

• Excellent warmth, thermal regulation, and quick-drying performance, even during exertion and in windy conditions

• Odor-resistant merino wool allows for multi-day use without frequent washing

• Comfortable, versatile athletic fit with functional features (scuba hood, two-way zipper, zippered pockets, thumbholes)

• Durable construction with minimal abrasion or pilling, easy to care for1

Cons:

• Not fully windproof—wind penetration occurs in very strong or high-altitude conditions (may need a shell layer)

• Some minor pilling over time, typical of natural fabrics

• Higher price; considered an investment piece

• Slightly bulkier than ultralight base layers due to added warmth and features

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Performance in windy conditions

Photo: Debbie Gonzalez Canada

About our test of this product

Here’s what Ibex claims the Ibex Mammoth Hoodie can handle: Made with Nuyarn technology, Ibex claims this is the warmest and most durable hoodie in its lineup. It’s built for skiing, climbing, and generally getting after it in varying conditions where the wind can fierce and cold. The brand calls it the “Wooly Mammoth” of hoodies.

Where we tested the Ibex Mammoth Hoodie: Argentinian Patagonia

Why we chose this location:
The weather in Argentine Patagonia is defined by its extreme wind, unpredictable conditions, and generally cool temperatures year-round. The region’s wind is not just a notable feature—it’s a defining element of daily life and landscape.

The first couple of days, I was happy with how comfortable and versatile the hoodie was (I wore it during hikes and also took it to the theater when I went to see a musical). I knew merino wool naturally regulates temperature, wicks moisture, and resists odor, which is what makes it suitable for multi-day adventures without the need for frequent washing. This is all true for this garment. The scuba hood was definitely a highlight from the start, because it provided extra coverage for my head and neck — critical areas for retaining heat in windy conditions.

It was only after a hypoglycemic episode during a hike that I realized how amazing the fabric is. When my blood sugar goes down, I sometimes sweat profusely in a way that does not stop until I eat something with sugar or carbs. I can’t simply remove layers to stop sweating. Without the right fabrics, this would have sucked on a cold, windy day, because I would have ended up with wet clothing and extremely cold. Ibex’s hoodie helped me stay warm, and it dried up quickly as soon as I ate and recovered from the hypo. This merino wool item truly excels at thermal regulation.

I should note, though, that when the weather was at its windiest and coldest, I wore the Mammoth Hoodie as a midlayer (as expected). Despite its improved air resistance, the Mammoth Hoodie is not fully windproof. In sustained, strong winds or at higher elevations, some wind penetration was inevitable — a common trait of merino-based midlayers. For truly blustery days or summit pushes, I would pair the hoodie with a lightweight wind shell or hardshell jacket.

Technical features of the Mammoth Full Zip Hoodie (why it worked so well)

Photo courtesy Ibex

Ibex Mammoth Hoodie technical specs:

• Exterior fabric: 85 percent merino wool, 15 percent nylon, 310gsm, 21-micron gauge

• Interior fleece: 78 percent merino wool, 22 percent nylon, 145gsm, 18-micron gauge

• Nuyarn® technology for enhanced warmth, elasticity, and durability (up to 35% more thermally efficient, 85% more elastic, nearly 9x as durable as standard ring-spun wool)

• Performance fit, full-length two-way belay zipper, 3-panel scuba hood with elastic binding

• Gusseted underarm side panels, offset shoulder seams for comfort

• Harness-compatible, zippered hand pockets, zippered chest pocket, internal drop pockets

• Low-profile horizontal thumbholes, locker loop for easy hanging

• Designed for alpine and cold-weather use

The Mammoth Hoodie’s fabric is a combination of high-quality merino wool and a bit of nylon (the exterior is 85 percent Merino Wool, 15 percent Nylon, and the interior fleece is 78 percent Merino Wool, 22 percent Nylon). The fabric on the exterior has 21 microns, and the one on the interior, 18 microns (for those of you new to merino wool, the finer the micron, the softer the fibre). Ibex promotes the particular spinning technology, called Nuyarn®, that makes this hoodie more thermally efficient, elastic, and durable than traditional ring-spun wool. In plain English, it is a dense knit, both soft and tough, resulting in a long-lasting piece of gear that traps warmth while maintaining breathability.

The hoodie has an athletic fit and is true to size. It comes with the aforementioned scuba hood (helmet compatible) and thumbholes, as well as zippered chest and side pockets. I chose the black one, but it also comes in a wonderful “moonrock” color (like the image above). I simply went with the darker tone because I thought it would be more stain-resistant during outdoor activities.

Durability, Care, and Maintenance

Photo courtesy Ibex

Ibex claims the hoodie can resist pilling and abrasion, even when worn under a backpack or harness. I haven’t used the hoodie for long enough to attest to its durability over years of use. I noticed just a tiny bit of peeling in one or two areas, which is to be expected with natural fabrics.

Merino wool is easy to care for: wash with like-colors, avoid fabric softeners and bleach, and line dry. The hoodie does not really need ironing, but if you insist, only use a cool iron. Because merino wool has natural odor resistance, less frequent washing is required. Washing it less helps prolong the garment’s life.

For anyone who values warmth, comfort, versatility, and technical performance, the Mammoth Hoodie is an investment that delivers on its promises. While it won’t replace a dedicated windproof shell in extreme conditions, this hoodie, engineered to be more air-resistant than conventional merino, helps to block a significant amount of wind while still allowing excess heat and moisture to escape.

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