Merino Wool vs Synthetic Baselayers: Our Experts Weigh In

Should you wear merino or synthetic baselayers? It’s an age-old question for hunters. Learn everything you need to know as John Barklow and Chris Derrick from our product team take a deep dive into the distinct advantages of wool and synthetic fabrics and how to choose the right one for your hunt.

One of the questions Derrick gets asked most often is, “What’s the right baselayer?” Whether merino wool or a synthetic baselayer is best for you depends on several key factors. We’ll tell you what you need to know about cost, moisture management, comfort, odor control, warmth, aftercare, and more. 

The Quick Answer

Merino wool generally performs best for less active hunts (like whitetail hunting from a stand), while synthetic baselayers are generally better for active hunts. But there’s a lot more to it than that.

Key takeaways:

• Choosing between merino wool vs. synthetic baselayers depends on the hunt, with merino generally better for stationary hunts and synthetic better for active hunts.

• Synthetic baselayers move moisture away from the skin faster, while merino wool manages moisture more slowly and helps prevent the quick chill synthetics can cause.

• Merino wool offers better odor control than synthetic fabrics, often letting hunters wear merino baselayers for 3 to 5 days before needing to wash them.

• For cold-weather performance, merino is generally warmer gram for gram and stays warm when wet, but it dries more slowly than synthetics.

• Lightweight 120- or 150-gram merino and synthetic baselayers work in warm weather, although merino can retain moisture and become less suitable in extreme heat.

Baselayer Basics: Getting the Foundation Right

Too many hunters dismiss or overlook the importance of their baselayers. They’ll plop on some cotton undergarments, then they wonder why the rest of their system doesn’t keep them warm. “Many overlook it, but the baselayer is foundational to the system — everything else layers on top of it,” Barklow says. When you treat your baselayers as the foundation of your system, it starts you off on the right foot and lets the rest of your clothing system perform as designed. 

A good hunting baselayer should move moisture away from your skin to reduce conductive heat loss. “In a cold environment, if we can keep our skin dry and that layer directly next to our skin, then we’re going to feel more comfortable,” Barklow says. A poor baselayer doesn’t move moisture away from your skin efficiently, which keeps the other layers (mid and outer) from providing the warmth and protection hunters need.

Lightweight baselayers, such as 120- to 150-gram weights, can also be used in warm environments. Synthetic baselayers are excellent at drawing sweat and heat away from your body to help keep you cool in warm environments. Wool holds sweat a little longer, which can make it more uncomfortable on warm days. 

The two main categories of baselayers are merino wool and synthetic fabrics, such as polyester. Each offers different pros and cons for hunters. Depending on how you hunt, one type of baselayer may make more sense. One deciding factor is cost.

What’s the Most Cost-Effective Baselayer? Merino Wool vs. Synthetic 

As a natural fiber produced by sheep, merino wool is typically more expensive. “If you’re looking for some of the properties from merino, you’re going to have to invest more money,” Derrick says. For this reason, synthetic baselayers are often considered the more budget-friendly option.

Another reason synthetic baselayers can be more cost-effective is that they tend to be more durable than wool. However, merino can now be durable as well thanks to SITKA’s ArmorSpun Merino Wool. The yarns used to create ArmorSpun baselayers are made by wrapping merino wool fibers around a durable nylon core, providing the benefits of both merino and synthetic in the same garment. “With ArmorSpun, the greatest improvement is in abrasion-resistant properties,” Derrick says.

About SITKA’s ArmorSpun Merino Wool

We pushed nature's best fiber to its limit in our labs. The result is a more durable merino wool sealed in nylon for improved abrasion resistance while keeping its lightweight warmth, comfortable feel, and natural odor resistance.

Merino Wool vs. Synthetic Baselayers: Moisture Management, Comfort & Odor Control

Merino wool and synthetic baselayers have different performance characteristics you’ll want to consider when deciding which is right for you on any given hunt. Since this is the only layer that touches your skin, these factors really affect how you feel throughout the day—or a whole trip—out in the field. Here are a few traits of each that may go into your decision process:

Moisture Management

Barklow says, “There’s no doubt, moisture management is the number one thing for a baselayer.” Synthetic baselayers pull moisture away from your skin faster and more efficiently than merino wool. According to Barklow, wool “almost feels like it steams you dry.” This is one reason synthetics are most often preferred by active hunters, and wool by stationary hunters. However, in cold environments, synthetics can feel like they’re pulling your body heat away because they manage moisture so efficiently. Wool doesn’t give you the quick chill you can experience with synthetics. 

Comfort

Your baselayers should be intentionally designed to keep you comfortable, whether you're sitting still or on the move. They must layer well and shouldn’t create pinch points, bunch up, or restrict your movements. Historically, wool has had a reputation for being itchy, but modern fabric science has let us create wool products with ultra-fine 17-micron fibers. These modern merino wool fibers solve the itch problem caused by coarse old wool fibers. “From a comfort standpoint, (both merino wool and synthetic) are ideally suited,” Derrick says. “You can’t go wrong with either, if you get the right type of merino.” 

With the new merino wools, breathability is essentially equal to synthetics. In the past, this wasn’t the case, but recent developments mean even heavyweight merino wools are more breathable than once thought possible. 

Odor Control

“I think this is the defining factor when it comes to people making the decision between merino and synthetic: the odor management properties… Merino undoubtedly wins when it comes to odor management,” Derrick says. Wool has natural antimicrobial properties, which definitely give it an edge when controlling odor. Synthetics try to mimic these properties with different chemical applications, like Polygiene^® Odor Control Technology. 

As hunters, we know reducing our odor to a minimum is critical because many of the animals we hunt depend on their sense of smell to identify threats. This is especially true for whitetail, which is just another reason why deer hunters typically gravitate to merino wool. Derrick says, “When whitetail hunting, I always gear towards merino.”

On longer hunts, keeping our body odor under control is more challenging. Merino wool baselayers are often worn for 3 to 5 days in a row on an active hunt before you need to wash them. Because synthetic fabrics like polyester absorb oils, sweat, and bacteria, you can generally wear a synthetic baselayer for only a couple of days on an active hunt before body odor becomes a problem. 

John Barklow on Merino Wool vs Synthetic Baselayers in practice.

What to Wear: Moisture-Wicking Baselayers From SITKA

If you’re unsure of what SITKA baselayers will work best for your next hunt, check out the options below. 

SITKA Lightweight Baselayers

Lightweight baselayers are great for warm-weather hunters when worn on their own and are the foundation for your cold-weather clothing system because they’re the best SITKA

• Core Lightweight Hoodie

• Core Lightweight Crew LS

• Core Lightweight Bottom

• Core Merino 120 Hoodie

• Core Merino 120 LS Crew

• Core Merino 120 Bottom

• Core Merino 120 SS Crew

SITKA Midweight Baselayers

Midweight baselayers are an excellent foundation for cold hunts, from mid-season through late season. Warm climate hunters rarely need more than a midweight baselayer.

• Core Merino 220 Half-Zip

• Core Merino 220 Bottom

• Core Merino 220 Boxer

• Solace Hoodie

• Core Midweight Bottom

SITKA Heavyweight Baselayers

When the temps drop and you need to stay warm on a blisteringly cold hunt, heavyweight baselayers are a must. 

• Heavyweight Hoodie

• Heavyweight Bottom

• Core Merino 330 Hoodie

• Core Merino 330 Half-Zip

• Core Merino 330 Bottom

• Core Merino 330 Zip-Off Bottom

Baselayers for Temperature Regulation

SITKA baselayers work well in cold and warm weather when used properly. Here’s how to choose the best baselayer for the temperatures you plan to hunt. Derrick says two misconceptions people have about baselayers are that merino is only for cold weather and synthetic is only for warm weather.

How to Use Baselayers to Trap Heat in Cold Weather

Traditionally, baselayers were used to keep you warm when temperatures drop. Gram for gram, merino wool is generally warmer than synthetics like polyester or nylon. Merino traps heat and is warm when wet. However, merino dries much slower than synthetics, so if you get soaked to the bone in wool, you’ll stay wet longer, which can make a hunt miserable. Prolonged exposure to cold while wet can also increase the risk of hypothermia.  

Baselayers perform the best in cold weather when they’re used as part of a system. Many people mistakenly believe that as long as they wear thick, heavy clothing, they’ll be warm. That simply isn’t true because thick, heavy clothing isn’t designed to wick moisture, and when it gets wet, it stays wet. Wearing baselayers helps manage moisture without restricting crucial blood flow and creates room to trap body heat. You can also double up on your baselayers when it turns brutally cold. Wearing a lightweight baselayer next to your skin, with a mid- or heavyweight insulation layer on top, and finally an outer shell, will keep you warmer than wearing extra-thick clothing.

How To Use A Baselayer For Keeping Cool In Warm Weather

Until fairly recently, most people wouldn’t have considered wearing a baselayer in warm weather. “We’ve been able to get our merinos so light, they're a great choice for hot weather,” Barklow says. Lightweight 120- or 150-gram merino wool and synthetic baselayers make excellent warm- and hot-weather attire because they’re both breathable and pull sweat away from your skin (convective cooling). Because it retains moisture, merino wool doesn’t cause rapid heat loss, so in extremely hot cases it’s not the best option. 

Which Is the Easiest Baselayer to Care for? Merino Wool vs Synthetic

It wasn’t long ago that synthetic baselayers were the clear winner for being the easiest to clean and dry, but merino wool products have improved significantly in recent years. “The wonderful things about the merino we’ve developed are that I can take all my hunting gear off, I can throw it in the washer, and then I can put it in the dryer on the normal setting, and they can all be dried together, and you're not going to come out with a sweater that is half the size it used to be,” Derrick says. ArmorSpun merino wool was intentionally designed for easier aftercare. “The merino we’ve made, you can wash and dry it just like everything else.”

Synthetic baselayers remain simple to care for. “Synthetic, you can wash it in a creek, wash it in the washing machine, you can wash it with everything. You don’t have to do anything different. The nice thing is when you pull it out of the washer after a spin cycle, it’s almost completely dry,” Barklow says. 

Summing Up: Merino Wool vs Synthetic Baselayers — Pros & Cons

Merino Wool

• Moisture wicking: Wicks moisture away from the skin slowly, but stays warm when wet.

• Temperature regulation: Better for cold weather, but still usable in warm weather.

• Odor control: Better at controlling odor, allowing you to wear it for around 3–5 days without washing.

• Value: Typically more expensive because it is a natural fiber.

• Aftercare and durability: Thanks to ArmorSpun technology, merino wool is easier to care for and more durable than ever.

Synthetic Baselayers

• Moisture wicking: Wicks moisture away from the skin quickly.

• Temperature regulation: Performs well in both warm and cold weather.

• Odor control: Not as effective at controlling odor, typically lasting around 1–2 days without washing.

• Value: Generally less expensive than merino wool.

• Aftercare and durability: Thanks to recent fabric technology advancements, synthetic baselayers and merino wool are now almost equally durable and easy to care for.

Overall Takeaway

Merino wool is a great choice for cold-weather comfort, natural odor control, and longer wear between washes, though it typically costs more.Synthetic baselayers are a more affordable option that wicks moisture quickly and works well across a range of temperatures, but tends to require more frequent washing due to odor buildup.

Overall recommendation: Barklow says, “I’m not anti-wool, but I am pro-synthetic.” Because synthetics have been more durable in his experience, he can wear them as outerwear in hot weather and layer them under other layers. He also likes that synthetics dry quickly on high aerobic, multi-day mountain hunts.

Barklow also mentions he now wears wool while whitetail hunting when he has a short walk to the stand and is less worried about sweating but more worried about managing body odor. 

FAQs About Choosing A Baselayer

What is the best baselayer for hunting?

The best baselayer for hunting depends on your activity level, conditions, and hunting style. Whitetail hunters who spend long periods sitting often prefer merino wool for its odor management, while active mountain hunters often prefer synthetic baselayers for their moisture management and quick drying.

Is merino wool synthetic?

No, merino wool is not synthetic. It comes from a specific sheep breed that produces finer wool than standard wool. ArmorSpun is a unique blend of synthetic and merino wool: merino wool fibers are spun around a synthetic (nylon) core, giving it the properties of both. 

At what temperature should you wear baselayers?

Most people start wearing baselayers when the temperatures drop below 50˚F, but lightweight baselayers also make excellent warm-weather (75˚F+) clothing.

How quickly does merino wool dry?

Merino wool typically takes 3-12 hours to air-dry, depending on humidity, airflow, and fabric thickness. 

What are the downsides of merino wool?

The downsides of merino wool are lower durability (though this has improved in recent years), higher price, and that it holds onto water longer.

Are baselayers better than thermals?

Yes, baselayers are better than thermals in most hunting situations because thermals are made from cotton, while baselayers are made from wool or synthetics that wick moisture while keeping you warm. 

How tight should a merino baselayer be?

Your merino baselayer should be snug but not restrictive or painful. It shouldn't cut off blood flow, but it should feel like a second skin. 

Should I size up or down in merino wool?

You should stick with your normal size in merino wool. It naturally stretches, and you don’t want it to be loose or baggy. Modern merino wools, like SITKA ArmorSpun, don’t shrink when washed and dried.

How many days can you wear a merino baselayer?

You can wear a merino baselayer for 3 to 5 days in a row before it needs to be washed due to odors. 

How often should you wash merino wool baselayers?

You should wash merino wool baselayers after 3 to 5 days of heavy use, or once you notice they smell. 

Why does merino wool smell after washing?

Merino wool smells after washing because water (especially hot water) activates the natural lanolin oils. It smells earthy or animal-like when it’s wet, but the smell fades as it dries. Other reasons include detergent residue. You can avoid the smell by washing merino wool in cool water, using special detergents, and drying it completely before storing it. 

What happens if merino wool gets wet?

When merino wool gets wet, it loses strength and stretches. It also creates an exothermic reaction because the porous fibers absorb water molecules, creating a small amount of heat. This is why wool remains warm when wet.