Modal vs Merino Wool: Which Base Layer Fabric Wins?
Modal vs Merino Wool: Which Base Layer Fabric Wins?
These two get lumped together because both feel soft. They behave very differently once you sweat, once you wash them, and once you have owned them for two winters. Here is an honest comparison.
Ask ten people for a warm base layer recommendation and you will get ten answers, split roughly between merino wool and everything else. Merino has genuine virtues. It is also the fabric most often abandoned after one season, usually because of the washing instruction rather than the wearing experience.
Every long john we make is built in 95% Modal, so this is not a neutral comparison. But we would rather explain the trade honestly than pretend one fabric wins everything, because the right answer genuinely depends on how you will use the garment. That is the whole modal vs merino question in one line: there is no winner, only a better match for a specific use case.
Modal vs Merino Wool: The Core Differences
Modal and merino are both plant- or fibre-based, both soft, and both good at managing moisture. The differences are about warmth when wet, how they feel over time, and what they cost you to maintain.
Merino is warmer when damp
This is merino's genuine technical advantage and nothing else matches it. Merino wool fibres can absorb up to around 30 percent of their dry weight in moisture while still feeling dry to the touch, and they release that heat as the moisture moves out. This is why merino stayed the default for expedition base layers for decades, and why it still dominates the merino wool long johns category among people who spend real hours in the cold.
Modal stays comfortable for longer
Modal is a regenerated cellulose fibre made from beech wood pulp. It is smooth and nearly frictionless against the skin, which is where its reputation comes from. It also handles repeated washing badly in the sense that it simply does not need special handling. No cold hand wash, no drying flat, no careful maintenance routine.
Modal is weaker wet than dry, so it is not the right choice for a garment you will keep damp for hours. For a base layer you wear for a day and then wash, that weakness is irrelevant.
The core differences between modal and merino wool
| Merino wool | Modal | |
|---|---|---|
| Warmth when wet | Excellent, retains heat while damp | Good, but loses some warmth if soaked |
| Next-to-skin feel | Soft if fine micron count; can feel warm and damp if worn for days | Very smooth, cool, low friction |
| Itch | Varies hugely with micron count; coarser merino is itchy | Not itchy |
| Odour resistance | Excellent, naturally odour resistant | Good, but not as good as merino over multiple days |
| Care | Cold hand wash or wool cycle, air dry, do not tumble | Machine wash warm, tumble safe |
| Durability | Very high if cared for | High for daily use, weaker wet |
| Price | Higher, especially at fine micron counts | Moderate |
| Best for | Multi-day cold trips, high output in cold, people who re-wear a base layer | Daily wear, commuting, cold weather without adventure |
If you will wear the same base layer for three days without washing, merino is genuinely better. If you will wash it every night, modal is the more sensible purchase.
Warmth When Damp: Merino's Real Advantage
Here is the mechanism that makes merino worth the price. Wool is hygroscopic, meaning it pulls water vapour out of the air and holds it inside the fibre rather than on the surface. Surface moisture evaporates and cools you; moisture held inside the fibre does not.
So a merino base layer in damp conditions feels warmer than a synthetic or modal layer in the same conditions. Cotton is the opposite: it absorbs into the fibre, stays heavy and cold for hours, and takes a long time to dry. This is why cotton is a poor choice for anything active, and why merino displaced it for cold-weather work.
Modal sits in a reasonable middle. It wicks well when it is a fabric blend and it dries quickly, but it is not engineered to keep you warm while saturated. If your plan involves getting properly wet and staying that way for a while, merino is the safer pick.
Itch, Softness and Why Micron Count Matters
Merino's reputation for itch is mostly a matter of fibre diameter, measured in microns. Finer merino fibres bend more easily and sit flatter against the skin, so they feel soft. Coarser fibres poke, particularly when the skin is dry or the garment is worn for several days without washing.
Anything under about 19.5 microns is generally considered comfortable next to bare skin. Above 22 microns, expect some prickle, especially at the neck and cuff seams where the fabric folds and presses.
Modal has no equivalent variable. It is uniformly smooth and non-itching, which is a large part of why people who find wool unappealing do not have a problem with it. If you have previously rejected merino for itch, that is a fibre diameter problem, not a fabric problem, and a modal blend avoids it entirely.
Care and Maintenance: Where Merino Loses People
Merino's most common failure is not wear, it is laundering. Most people who dislike merino have never actually worn a well-cared-for merino garment; they have worn one that was repeatedly hot washed and tumble dried, which felt the fleece to shrink and harden and pruned the loft that makes it warm in the first place.
If you buy merino, the routine is simple:
- Wash cool, ideally 30C, on a wool cycle or by hand.
- Use a wool-safe detergent. Regular detergent contains enzymes that break down protein fibres like wool.
- Dry flat or on a drying rack. Tumble drying is what does the real damage.
- Air it out between wears instead of washing daily.
Modal needs none of this. It survives a normal warm wash and a tumble dry without losing shape or softness. If your laundry routine does not allow for careful garment care, choosing a fabric that tolerates it is worth more than choosing the technically superior fibre.
We are not going to pretend otherwise: the most sustainable base layer is the one you keep wearing and stop replacing. If merino would end up in a drawer unwashed because the care routine feels like too much friction, a modal garment you actually use daily is the better outcome.
Merino Price vs Modal Value Over One Winter
Merino base layers sit at a higher price point, and the gap widens with micron count and brand. Modal and cotton blends cost meaningfully less.
On raw price per wear, merino can win. If a fine merino garment lasts five winters at 30 wash cycles and costs three times as much as a modal garment lasting two winters, the maths works out in merino's favour.
On likelihood of continued use, modal often wins, because a garment that gets worn is worth more than one sitting in a drawer. There is also a middle path that many people like: a merino-blend garment rather than 100 percent merino. Blends improve durability and reduce the price while keeping most of the moisture benefits.
Which Fabric Should You Choose for Cold Weather?
Decide by use case rather than by which fibre sounds more premium.
Choose merino wool if you will wear the same garment for multiple days without washing, you are doing high-output activity in cold conditions, you are buying a highermicron-count garment for next-to-skin wear, or you already prefer wool and know how to wash it.
Choose modal if you wear a fresh base layer every day, you are commuting or working indoors in a cold building, you want the lowest-friction feel against sensitive skin, or you want a garment you can machine wash without thinking about it.
Consider a blend if you are somewhere in between. A merino-modal blend gives up a small amount of wet warmth and gets back durability and easier care.
Why we settled on Modal for our long johns
Our long johns are built for daily winter wear, not for expeditions. That meant the deciding factor was never maximum wet warmth but whether people would keep wearing them. Modal gives a smooth, non-itching feel that stays comfortable through a full workday, and it survives a normal wash cycle without special treatment. If your use is multi-day and high output, merino is the better technical answer, and it is worth buying merino for that case even though we do not make it.
You can see the full range in our long johns collection, or read the garment-level comparison in Long Johns vs Thermal Underwear.
Frequently Asked Questions
Is merino wool warmer than modal?
When both are dry, the difference is small and depends more on garment construction than fibre. When damp, merino is clearly warmer. Modal wins on comfort and ease of care in dry everyday conditions.
Is modal warmer than cotton?
Yes, in activity conditions. Modal moves moisture away from the skin and dries quickly, while cotton absorbs and holds it. In static cold, both are acceptable and the difference is less relevant.
Does modal shrink in the wash?
Modal is generally very shrink resistant, especially in a cotton-modal blend. Follow the care label and use cool to warm water. The main thing to avoid is prolonged high heat, which can still affect any cellulose fibre.
Is merino worth it for everyday winter use?
If you are wearing a fresh base layer daily, merino's main advantages are not being exercised, and a modal blend is usually the better value. If you will wear the same garment for days in the cold, merino earns its price.
Can I wear merino and modal together as layers?
You can, but you do not need two synthetic-type layers doing the same job. Wear the thinnest wicking garment against your skin and add a heavier layer over it. Our what to wear under long johns guide covers the correct order.
Which is better for sensitive skin?
Modal, without much qualification. Merino can be excellent at fine micron counts and uncomfortable at coarser ones. If you react to wool, a modal or cotton-modal blend avoids the issue entirely.
Still deciding what to layer? Read Long Johns vs Thermal Underwear first, then come back to what to wear under long johns for the full system.
