Best Merino Wool Clothing (2025): Base Layers, Hoodies, Jackets & More

Merino wool is an incredibly versatile fiber. The finest merino wool garments excel in keeping you comfortable even in extreme heat of 95 degrees Fahrenheit, while merino base layers ensure warmth in frigid conditions well below freezing. Unlike synthetic materials created from petrochemicals, merino wool is a natural, renewable resource.

The adaptability of merino wool leads to an extensive variety of blends and styles available in the market. Here are some of our top merino wool products that we’ve rigorously tested through wearing and washing (typically in cold water and air-dried) over several months, and in some cases, years. After reading this, make sure to explore the rest of our apparel recommendations, like the Best Puffer Jackets, Best Hoodies, and Best Hiking Boots.

Updated March 2025: We’ve included new base layers and T-shirts in our recommendations and refreshed links and prices throughout the content.

Table of Contents

What Makes Merino Wool Exceptional?

Merino wool is excellent due to its natural ability to regulate temperature, akin to the way sheep adapt to their environment. If you’ve only worn those scratchy wool sweaters that your grandmother supposedly knitted, you might be perplexed by its acclaim. The truth is, Merino sheep produce finer, softer wool, which provides comfort across a broad temperature spectrum and is gentle against the skin. Additionally, wool is a sustainable material.

Annually, one merino sheep yields 4 to 5 pounds of wool, attributed to their consumption of pure alpine waters and their unique upbringing. Just for fun, picture them being mentored by the posh Pashmina goats, who certainly excel in the realm of luxurious softness. This playful imagery aside, the exceptional quality of merino wool has inevitably become a staple in my wardrobe.

Merino wool is available in various weights, often denoted as “200 GSM” or similar terms. (GSM stands for grams per square meter, occasionally written as g/m.) The key factor is the weight classification and how your garment fits within that scale. Lightweight garments like T-shirts and underwear typically start at around 150 GSM, while anything below 200 GSM makes for a suitable base layer or T-shirt. The mid-range is from 200 to 300 GSM, with heavier items falling above 300 GSM.

For those more accustomed to synthetic material ratings, it’s worth noting that approximately 120–160 GSM wool equates to a 100 weight fleece, 160–200 GSM wool correlates with 200 weight fleece, and anything over 200 weights like 300 weight fleece. Always remember that wool is warmer as it has superior heat retention properties, especially in windy conditions (though there are reasons to opt for fleece in certain situations, including its remarkably lightweight nature).

Caring for Merino Wool

Most merino products will include care guidelines. Usually, these guidelines advise washing in cold water and laying flat to dry. The latter is crucial since hanging a wool item to dry may cause it to stretch due to the water’s weight. While many merino labels endorse machine washing, based on my experiences, hand-washing tends to prolong the garment’s lifespan. This is particularly true for lightweight (150 GSM) merino base layers and T-shirts. An exception is Minus33’s Microweight Raglan short sleeves, which can handle machine washing and drying; I’ve subjected mine to both processes for over a year, and it’s held up remarkably well.

I’ve never faced issues maintaining merino in my closet between wears, but for prolonged storage, safeguarding against moths is wise, as they are notorious for damaging wool. I’ve lost merino pieces to moths before.

If you wish to avoid mothball odors, there are alternatives. I ensure to wash and thoroughly dry anything I store, then I place it in a compression bag. Another method is to put your merino items in a cotton bag or wrap them in cotton, placing them in a plastic container. Ensuring the garment is entirely dry before utilizing any of these storage options is paramount; otherwise, it may develop a musty or moldy smell. Other efficient options include storing garments within a cedar chest—which acts as a moth deterrent—or using moth traps or lavender sachets to repel these pests.

100 Percent Merino vs. Blends

Should you opt for 100 percent merino or a blend? The answer is … it varies. It depends on the specific garment, your intended use, and your personal preferences. The best way to determine your preference is to experiment with several options and see what suits you. Blends tend to have a stretchy quality, making them better for active endeavors like hiking and climbing, while I prefer 100 percent merino for heavier mid-layers such as hoodies or jackets. My experience suggests that the closer the fabric is to my skin, the more inclined I am to choose blends, with Nuyarn being my leading choice for base layers.

Moreover, some alpaca blends available are impressively soft (I’ve loved all choices from Paka and Arms of Andes). If you happen to be among the rare group that finds merino itchy, you might have an allergy to lanolin, the natural skin oil produced by sheep. Alpacas do not produce lanolin, and their fibers are both thinner and finer than merino, making them warmer and softer, albeit at a higher cost.

Merino vs. Synthetic Fibers

Which option is superior? Once again, it depends (apologies). Nonetheless, merino typically holds an edge. When I refer to synthetics, I generally mean polyester, nylon, polypropylene, rayon, or blends of such fabrics—essentially anything other than cotton, wool, or linen.

Synthetics often excel in wicking moisture away, giving them an inherent dryness. They also tend to dry quickly, making them preferable for items like socks and underwear, with many “merino” options exceeding 50 percent synthetic fibers. Synthetics perform better when managing moisture. The significance of this varies based on individual preferences. Personally, I feel odd and somewhat clammy in synthetic materials, rendering moisture management less important.

However, the downside to their moisture-wicking properties is that synthetics tend to retain odors. Some chemical treatments can help, but I haven’t encountered any synthetic product that matches the odor-resistance of merino wool.

Another area where merino excels is breathability. While synthetics perform adequately, merino truly shines in this aspect. If you’re hiking up a sun-exposed slope, then transitioning into a cooler environment, merino will keep you comfortable thanks to its breathability, which helps mitigate sweat. Again, the importance of this varies based on personal physiology.

Lastly, it’s crucial to consider durability. In some cases, synthetics might outlast pure merino, particularly in situations where abrasion is a significant wear factor. To my way of thinking, this further justifies selecting a merino blend over opting solely for synthetics, especially for off-trail hiking or rock climbing where your clothing may endure rough treatment.

Base Layers

To truly appreciate the wonders of merino wool, begin with the foundational layers next to your skin. Merino excels as a base layer, being warmer for its weight, effectively wicking moisture away, and unlike synthetic materials, merino remains odor-free even after days of wear. Below are our top-tested merino wool base layer tops and bottoms. Don’t forget to check out our layering guide for additional insights on how to combine layers and ensure comfort in varied climates.

Best Lightweight Base Layer

The Ibex Woolies Pro Tech base layer crew stands out as the best lightweight merino base layer we’ve tested. It’s a durable option designed for heavy use. The Woolies are crafted using Nuyarn, comprising 85 percent merino wool and 15 percent nylon—allowing the merino wool to envelop a nylon core, enhancing warmth while remaining lightweight (5 oz for the men’s large) and more resilient. This has become my go-to for all technical activities, suitable for hiking and backpacking, and Adrienne So, our reviews editor, also cherishes it for running, climbing, and other high-energy pursuits in chilly conditions. I’m also fond of the Woolies Pro Tech Bottoms ($115), which are ideal for backpacking except in warmer climates. A quarter zip version is available for those who prefer that style.

In addition to comfort and warmth, a key reason we endorse Woolies is their longevity. Ibex represents a legacy brand within this sector, having been established in 1997 and consistently producing high-quality merino garments since. Adrienne’s parents purchased her two pairs of Ibex base layers back in 2001, which she continues to wear as of 2025. With proper care, Woolies can provide warmth and comfort for many years.

Best Midweight Base Layer

When seeking a slightly warmer alternative to the lightweight Woolies, I turn to Smartwool’s Classic long sleeve base layer. These shirts are arguably the most sought-after merino shirts online, and for a good reason: they offer exceptional comfort, are cut on the looser side, feature robust seams (ensuring durability), and have a shoulder design promoting comfort during pack wear. Composed of 87 percent merino wool (with a nylon blend), they excel in durability while retaining lightweight characteristics (10.3 oz for a men’s large). I’ve donned this Smartwool shirt and its matching pants ($115) throughout a brisk Wisconsin winter.

Best Heavyweight Base Layer

If you plan to tackle bitter cold, consider Minus33 as your preferred brand. This company categorizes its product as midweight, yet I categorize it as an ideal heavyweight base layer for snowy conditions. It delivers a soft feel, and when paired with the Minus33 Expedition weight hoodie below, it’s adequately warm for winter hiking and snowshoeing. The seams remain comfortable even with a heavy pack, and the fit is roomy without being excessive. I’ve tested this shirt for over a year, and it appears as pristine as it did on day one, showing minimal pilling and no fraying. Note that the women’s variant is named the Ossipee, but functionally it mirrors this shirt.

The aforementioned choices feature what my wife describes as “that sporty look,” more officially identified as “technical.” In contrast, the 100 percent merino shirt from Unbound resembles a more traditional long-sleeve shirt. It is incredibly soft, and while it can pill if placed in the dryer (which I advise against), it has demonstrated substantial durability—I’ve been wearing it consistently for over a year, and it looks just as it did upon purchase. This shirt’s thin design makes it perfect for cool mornings during the transitional seasons. It’s also versatile; useful as a base layer or a standalone T-shirt when temperatures are mild. The fit aligns with standard sizing, and if a particular size is sold out, it’s wise to be patient, as Unbound often refreshes its inventory.

Other Notable Base Layers:

REI Merino 185 Base Layers for $80 (Men’s): These budget-friendly merino base layers from REI are a solid choice, offering comfort and warmth without significantly impacting your finances. The bottoms and leggings are also highly recommended (Men’s/Women’s).
Ridge Merino Aspect Midweight Base Layer for $75 (Men’s): This is one of the rare base layers suitable enough to be worn as a standard T-shirt in casual environments, making it a versatile selection.
Bombas Merino Wool Blend Long-Sleeve Shirts for $74: For those seeking a softer shirt, these blend 50 percent woof with Tencel, a lightweight fiber sourced from eucalyptus. This shirt offers warmth and protection with a UPF 50 rating when exposed to sunlight.
Kari Rose Base Layer Bottoms for $110: As a petite 5’2″, finding fitting options can be challenging, especially for items meant to be close-fitting. Even top-quality base layers will fall short if they shift around your waist or sag below your hips. Kari Traa’s leggings feature a very high waist to ensure they stay put. The delightful patterns are an added bonus for anyone hesitant to sport what looks like pajamas in a lodge. —Adrienne So
Artilect Boulder 125 Leggings for $120 (Men’s): My introduction to Nuyarn, these base layer pants are exceptional for active use—they boast ample stretch and flexibility thanks to strategically placed fabric panels and stitching. They’re quite thin but snug, making them ideal for running during brisk mornings.
Ridge Aspect Midweight Merino High Rise Bottoms: An outstanding choice for women seeking versatility, suitable for both daily wear and the trails. My daughter even wore these under shorts for no-gi jiu-jitsu, and their durability impressed me.

Merino Mid Layers

While fleece has its benefits, I’ve shifted primarily to merino for mid layers. It excels in temperature regulation. Fleece still excels for backpacking due to its lightweight quality for comparable warmth, but my preference leans towards merino.

An Icebreaker hoodie introduced me to merino wool, and it remains my ultimate go-to jacket. Unfortunately, after nearly a decade, mine fell victim to moths (refer to our care guide) and had to be retired. While my hoodie isn’t the exact style shown, it closely resembles it. This garment is composed entirely of wool and offers remarkable warmth despite its slim profile, making it suitable for days with fluctuating weather—keeping you warm on a frigid morning while remaining easy to carry throughout the day. The fit leans towards snug, so if that’s not your preference, consider selecting a larger size.

Best Heavyweight Hoodie

Much like the McRib or the Northern Lights, the thickest Ibex wool hoodie is a rare delight that generates excitement upon its release. The Mammoth Hoodie truly is a considerable piece of clothing—equivalent to the American Giant hoodie in weight, but constructed with an 85% wool and 15% nylon mix for enhanced warmth and flexibility. Ibex claims it’s the warmest hoodie they offer, and from my experience, I’ve tested it in mid-30s temperatures, opting to use it as a substitute for a jacket. The athletic cut includes zippered pockets and thumb holes. Given my large head, I pair it with a stocking hat since the scuba-style hood is designed to fit beneath a helmet and may not provide sufficient warmth alone. —Martin Cizmar

Other Recommended Hoodies:

Ibex Men’s Indie Hoodie ($170): WIRED’s commerce director, Martin Cizmar, has expressed that this midweight wool hoodie has become one of his favorites. The merits of good wool speak for themselves.
Ridge Merino Hyde Hoodie ($150): This hoodie comprises 100 percent merino wool with a luxurious 275 GSM terry weave. Its midweight construction suits cool autumn and spring days brilliantly. The full zippers, thumb holes, and pocket all enhance utility. Personally, I enjoy this hoodie, though its longer cut can create an oversized appearance despite being a proper fit. A similar variant exists for women.

Merino wool options for children are quite limited. It seems the economic viability for manufacturers diminishes with pieces that kids will outgrow swiftly. Consequently, it’s uncommon to find children-sized merino (as indicated below). Though this Minus33 hoodie lacks kid’s sizes, the extra-small women’s size fits my 10-year-old well and continues to do so as she approaches 11. Consult Minus33’s sizing chart to ensure a good fit for your children. If they do fit, this hoodie is remarkably warm (an essential factor as my daughter often feels cold) and durable enough to handle active child play—from tree climbing to exploring forests. Best of all, this hoodie can be machine washed and tumble dried without risk of shrinking or shape distortion, and color bleeding is not an issue.

Although Minus33 markets this as an expedition-weight base layer, for an adventure seeker not facing extreme conditions, it’s genuinely an oversized, comfortable pullover sweatshirt. My testing period was short, yet during that time, my wife claimed ownership, dubbing it her “security blanket,” and declaring it her most essential clothing item.

I wore it in various scenarios, from chilly mornings on the beach to campfires in winter, and even under a puffer jacket when temperatures dropped below freezing last winter. Throughout all of these situations, I remained comfortably warm. The relaxed fit allows it to layer over a base layer adequately while still being slim enough for a jacket to fit on top comfortably.

Recent studies highlight the presence of PFAs—hormone-disrupting chemicals often found in numerous sportswear brands, including leggings and sports bras. If, like me, you aim to replace synthetic clothing with natural fibers, Ibex’s 100 percent merino wool Shak Jacket should be your go-to substitute for conventional jackets, such as the worn-out Patagonia Better Sweater ($159).

I brought this jacket on a spring trip to Ireland. Its surprising weight and softness proved reliable in maintaining warmth on blustery 30-degree days, easily layering beneath my rain jacket and over a tank top, providing a stylish look suitable for dining out in western Ireland (“I like your jumper!” was a common compliment). —Adrienne So

Should goose down jackets raise concerns for you as insulation options, merino wool serves as a good alternative to synthetic insulation. Vests provide an excellent layering solution to keep your core warm without restricting arm mobility or adding excessive bulk. Layering Ibex’s Wool Aire Vest beneath my wool coat or rain jacket is ideal for evenings out or extended runs. —Adrienne So

The Best Merino Wool T-Shirts

You may question wool’s suitability for a summer T-shirt, but merino surprises as a comfortable option even in warmer temperatures. When humidity rises above 90 degrees Fahrenheit, I typically lean towards cotton or linen, yet anything below that threshold means I reach for merino wool. A plethora of merino T-shirt choices exists, but here are some of our top recommendations. Note that though I may favor crew neck styles, many of these also come in V-neck versions.

The Best Merino Wool T-Shirt for Travel

These are undeniably my favorite T-shirts. They rank as the softest, best-constructed, and best-fitting T-shirts I’ve worn—merino or otherwise. Their versatility is unmatched; I’ve used them for everything from summer backpacking to rolling in jiujitsu and lounging by the fire on cool autumn nights. They consistently deliver comfort without exception. Furthermore, their lack of branding is a feature I appreciate. Unbound’s Active Merino T-shirt ($95), tailored for workouts, is equally impressive but offers a tighter fit compared to the standard T-shirt.

The Best Technical Merino Wool T-Shirt

For outdoor activities like hiking, backpacking, or paddleboarding, this is my first choice. It’s lightweight (84 percent 145 GSM merino, 16 percent synthetic) in a jersey knit that provides softness along with comfort, neither too hot in the sunshine nor too cold. Additionally, it boasts durability (as evidenced by my years performing jiujitsu while wearing it, still in fine shape) and is machine washable. You can even throw it in the dryer; no cautious handling is needed.

The Best Women’s Merino T-Shirt

Artilect’s blend merging merino wool and Tencel (a fiber obtained from eucalyptus) excels in being astoundingly lightweight and adaptable. This summer, the Utili-Tee became my number one choice for climbing and backpacking. It remained soft and pleasant in tree shade, yet surprisingly breathable as temperatures soared 15 degrees upon reaching the sunlit area. The flat seams ensured no chafing while enduring backpack straps or harnesses, and although cut in a flattering slim fit, it did not restrict shoulder or arm movement. —Adrienne So

Other Remarkable T-Shirts:

Icebreaker Tech T-Shirt for $85: These Icebreaker merino shirts introduced me to the benefits of merino wool. They’re lightweight, yet surprisingly effective at blocking the wind and keeping warmth. These shirts may not be suitable for humid conditions; therefore, a blend would often be better in those scenarios. Please check the specific design details for your preferred Icebreaker T-shirt to ensure it’s not a blend.
Minus33 Algonquin T-Shirt for $70: With its comfort and loose fit, this 170-GSM T-shirt from Minus33 is an excellent pick for layering over other clothes in brisk conditions or wearing alone when the temperature rises. A reliable versatile option for use in all but the hottest parts of summer.
Paka Tee for $55 (Women’s): Although not merino, this tee blends organic cotton with Alpaca wool, offering such comfort that it deserves a mention here.
Arms of Andes Alpaca Wool T-Shirt for $75 (Women’s): While primarily focusing on merino wool, we also include this T-shirt made from alpaca wool, which astonished me with its warmth. Though lightweight, it insulates wonderfully, especially paired with a base layer in winter.
Unbound Merino Tank Top for $70 (Men’s): For a cooler option in warmer weather, this tank top makes a fantastic choice in humid environments. It is crafted entirely from merino (175 GSM) and lacks any logos or tags, which is an added benefit. Stock is frequently replenished, so check back later if your desired size is unavailable.

Socks, Underwear and Bras

Some may argue this is the true base layer; however, we won’t dwell on that too much. Merino wool underwear, socks, and bras surpass their synthetic alternatives. If you haven’t experienced this yet, prepare for a pleasant surprise. After evaluating many options in these categories, here are our top recommendations.

Merino wool is usually quite soft, but most products here are blends incorporating some nylon. Darn Tough socks have earned a reputation as a WIRED favorite, functional for skiing, hiking, climbing, and various activities. These blends vary in weight but typically hover around 50 percent nylon and 50 percent merino, permitting slightly swifter drying while keeping them warm and cozy. Darn Tough socks are also remarkably durable—my pairs are nearing two years of use without any wear or holes!

My personal favorite merino socks are from Minus33. I’ve accumulated several lightweight and midweight pairs, plus a single pair of the expedition-weight ones, which I seldom use because they’re thick and warm—ideal for temperatures plunging below zero. My pick among them remains the Lightweight Mountain Heritage Boot Wool Socks, perfect for hiking or casual use. While Minus33 hasn’t shared specific blend ratios for these socks, I estimate around 60/40 wool to nylon, delivering superb softness and flexibility.

Other Recommended Socks:

Carhartt Midweight Merino Wool Blend Crew Sock for $22: Despite my affinity for warm weather, I hold a disdain for socks. Any day I wear socks feels like a failure. Yet, these Carhartt socks (a gift from a concerned friend worried about my sockless sandal choices during winter) have impressed me. They are exceptionally warm, soft, and virtually odor-free.

The Best Men’s Merino Underwear

The term “wool underwear” may evoke images of lumberjacks from bygone eras wearing coarse long johns, but today’s merino underwear defies such stereotypes. Most commonly, these are blends containing some nylon.

Thanks to our WIRED followers for introducing us to Woolly. These 100 percent merino (190 GSM) boxers are excellent and affordable. They ventilate well and adapt to weather changes, keeping you comfortable even when outdoor temperatures shift from hot to cold—a scenario common in mountain hikes. They are a shorter version with a 4-inch inseam, but Woolly also provides an option in a longer style.

These are the sole pair of 100 percent merino underwear I’ve encountered (with elastic in the waistband, fully encased in wool), ranking among my favorites, especially in colder settings. They provide extra-length compared to other boxers I’ve tested. These are lighter at 170 GSM, but their higher merino content renders them the warmest option. After years of trying merino underwear, these have become my go-to unless it’s particularly hot outside.

Other Notable Underwear:

Unbound Merino Boxers for $45: Constructed with 84 percent merino wool, 12 percent nylon, and 4 percent Spandex for a comfortable stretch, Unbound’s boxer briefs are soft and suitable, even in warmer conditions.
Icebreaker Merino Anatomica Boxers for $45: Another exceptional pair of boxers, consisting of 83 percent merino, 12 percent nylon, and 5 percent elastane, these Icebreakers are on the shorter side. Icebreaker also markets a longer version that I’ve also tested, which is nearly identical, just a bit longer.
Ridge Merino Wool Boxer Briefs for $35: At 83 percent merino wool (170 GSM), Ridge’s boxers are coupled with nylon and spandex, resulting in a comfortable fit. They generally adhere to true sizing and have a 6-inch inseam.

The Best Women’s Merino Underwear

Branwyn produces what they term merino wool performance sets, which I appreciate for their Oeko-Tex 100 certification confirming that every garment undergoes testing against a minimum of 350 harmful chemicals. This is among the most esteemed consumer safety labels. It’s worth mentioning that because I have a smaller bust, Branwyn offers a Busty Bra ($58) for those needing support.

However, Branwyn’s offerings may not provide satisfactory support for high-impact physical activities like running. Yet, their Racerback Bra ($75) impressively utilizes merino wool to achieve enough compression for moderate-impact activities. The full coverage design minimizes issues presented by small straps and padding, enabling a smooth transition from cotton “everyday” underwear to tighter nylon “sport” options for active moments. —Adrienne So

Other Worthy Mentions:

Ibex Natural Briefs for $35: If you prefer a lighter option, Ibex’s natural briefs are quite comparable to breathable cotton underwear. Although I typically line dry my merino items, these look enough like standard cotton briefs that I mistakenly threw them in the dryer, shrinking them considerably; it’s advisable to size up if that’s a concern for you. —Adrienne So
Icebreaker Siren Bra for $35: This is my go-to bra, flaunting a blend of 83 percent merino, 12 percent nylon, and 5 percent elastane, fitting true to size and meeting my daily needs perfectly.
Wool& Roam Merino Bra for $70: While the softest fabric I’ve encountered rests in Wool&’s merino blend (68 percent wool, 25 percent nylon, and 7 percent spandex), it’s relatively pricey compared to other options, and sizing up is often necessary. —Adrienne So

The Best Everyday Merino Garments

I confess that when I composed this guide years ago, I primarily viewed merino wool as a fabric suited for outdoor activities. While it undoubtedly excels in this area, I discovered its suitability for various daily scenarios, particularly while traveling, as it can be worn multiple times without developing odors. I have explored merino wool pants, dress shirts, workout apparel, hats, and more, and below are my top recommendations.

Yes, merino wool pants exist! Merino wool in all forms! Initially skeptical, I’ve learned to appreciate them. Despite their name, these aren’t work pants akin to Carhartts but rather lighter with a fitted design, equipped with several pockets and a loop designed for tools. Ultimately, they function as casual pants that are neither overly heavy nor too light, featuring a fabric mix of 75 percent merino wool (450 GSM), 21 percent bamboo, and 4 percent elastane, allowing for some stretch.

These remarkably comfortable, casual sweatpants from Ridge Merino stand among the coziest pants I’ve experienced. While I wouldn’t typically exercise in them or jog (I’ve never attempted it), they excel at providing comfort for lounging at home. Composed of 100 percent merino wool (275 GSM) with what Ridge defines as a terry fabric, they mimic traditional sweatpants.

What happens when you need more than a T-shirt but already possess merino wool pants, underwear, and socks? This long-sleeve button-down shirt from Woolly fits that requirement. Offering a more formal touch while maintaining comfort, it’s still casual enough for business casual scenarios, making it a reliable selection. The only feature I find less appealing is slightly shiny fabric, but that’s purely a matter of preference.