Merino wool and synthetics solve the same problem in different ways. Synthetic moves sweat along the surface and dries fastest. Merino takes moisture into the fibre itself, keeps warming you when wet, and does not smell after days of wear. For short intense workouts synthetic wins; for multi-day wear, wool does.

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How does each material work?

The difference is not quality, it is mechanism. Once you understand it, the choice becomes obvious for any given situation.

Synthetic moves moisture along the surface

Polyester and polypropylene do not absorb water — the fibre is hydrophobic. Sweat travels along the surface of the threads, spreads over a large area and evaporates. That is why synthetic dries so quickly.

The problem arrives when you sweat faster than the fabric can evaporate. Moisture then sits between the fabric and your skin, the garment clings, and it starts to chill you when you stop.

Merino takes moisture into the fibre itself

Wool fibre has a water-repellent outer layer and an absorbent core. Moisture goes inside the fibre — up to about a third of its own weight — before the fabric feels wet to the touch.

The result is a different sensation: your skin stays dry even when the material has already absorbed a significant amount of sweat. Wool also releases a small amount of heat as it absorbs, which buffers the moment you start to cool.

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Which one does not smell?

This is where the gap is widest and easiest to verify from experience.

• Merino is naturally antibacterial. The fibre structure limits the environment in which odour-producing bacteria develop. Three days on the trail without washing is normal.
• Synthetic holds odour and accumulates it over time. After a few months of wear, the smell returns immediately on contact with the body, even on a freshly washed garment.

A practical test: smell a synthetic sports shirt you have had for a year. Then smell a wool one. The difference needs no explanation.

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Which keeps you warm when wet?

Merino. This is the difference that matters for safety in the mountains, not just comfort.

Wool retains part of its insulating properties while damp, because the air pockets in the knit remain. Wet synthetic loses more of its insulation and actively cools you in wind.

A real scenario: you sweat on the climb, reach the ridge, the wind picks up and the temperature drops 8–10 degrees. In merino you feel cool. In wet thin synthetic you feel a cold that does not stop.

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Which dries faster?

Synthetic, by a wide margin — typically two to three times faster.

That is a genuine advantage for:

• Short, very intense activity — running, cycling, the gym
• Washing on the road, when a garment must be ready by morning
• Humid climates, where evaporation is slow for everything

An important nuance: with merino, drying speed matters less, because it keeps warming you while damp. Synthetic’s fast drying partly compensates for a weakness that wool simply does not have.

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Which lasts longer?

Synthetic is more resistant to mechanical wear. Polyester fibres handle abrasion from packs, buckles and belts better.

Merino is more delicate but lasts years with proper care. The practical differences:

• Synthetic — harder to tear, but accumulates odour over time that washing will not remove.
• Merino — stretches more easily if washed wrong, but stays equally functional after years.
• A silk blend — the compromise: silk threads add strength to fine wool without adding bulk.

In other words, synthetic wears out physically; wool only wears out if you wash it incorrectly.

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Which is better for the environment?

Wool has a clear advantage here, but it is worth being honest about it.

• Synthetics shed microplastics with every wash — into wastewater and eventually into nature.
• Wool is biodegradable and breaks down naturally.
• Wool is washed less often, which by itself reduces water and energy use.
• But: wool production also has an environmental footprint — land use, water and animal welfare. Wool is not “zero impact”, it is lower impact.

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When should you choose which?

Choose merino if:

• You will wear the garment for several days without washing
• Temperatures swing widely through the day
• Your skin is irritated by synthetics
• You will sleep in it — in a hut, a tent, or as pyjamas
• Odour is a real problem for you

Choose synthetic if:

• The activity is short and very intense
• Budget is the main factor
• The garment will take heavy abrasion — under a heavy pack daily, for instance
• You need to dry clothes overnight in a wet climate

Combine them if you want the best of both. The model most hikers use is merino as the base layer against the skin plus a synthetic second layer over it. The first layer handles moisture and odour; the second takes the wear.

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Is the price difference worth it?

Merino costs significantly more per item. But the calculation is not per item, it is per use.

• For a multi-day trek, two merino sets replace four or five synthetic ones.
• Merino is washed less often, which extends its life.
• Synthetic gets replaced when the odour becomes permanent — usually after one or two years of active wear.

For someone who hikes a few times a year, synthetic is sensible. For someone wearing base layers daily, or spending days outdoors, wool works out cheaper over time.

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Frequently asked questions

Which is warmer, wool or synthetic?

At equal thickness the two are similar when dry. The difference appears when wet: wool keeps part of its insulation, synthetic loses more of it.

Does merino itch more than synthetic?

Fine merino (17–19 microns) does not itch for most people. People with sensitive skin often react worse to synthetics, because of the trapped moisture and bacteria in them.

Can wool and synthetic be worn together?

Yes, and it is the most practical solution. Merino as the base layer against the skin, synthetic or fleece as the second. The reverse order does not work — synthetic against the skin cancels out wool’s advantages.

Why do synthetic clothes smell even after washing?

The odour is held inside the fibre itself and ordinary detergents do not fully remove it. It builds up over time and reactivates as soon as your body warms the fabric. This is a well-known and largely unsolved problem with polyester.

Does merino dry fast enough to be practical?

Yes, usually within a few hours when aired. It is slower than synthetic but faster than cotton — and it stays functional while damp.

Which is better for everyday wear under clothes?

Merino, in almost every scenario. It is thin, invisible under a blouse, does not smell after a working day, and regulates between a cold street and a warm office. Synthetic was designed for sport, not for a full day indoors.

Where does cotton fit into this?

Outside it. Cotton absorbs water and holds it, stays wet for hours and chills you. For sport and the mountains it is the worst of the three — which is why the comparison is between wool and synthetic, not with cotton.

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In short

• Synthetic moves moisture along the surface and dries fastest.
• Merino takes moisture into the fibre, warms you when wet and does not smell.
• For short, intense activity, synthetic is the practical choice.
• For multi-day and everyday wear, merino wins convincingly.
• The best solution is a combination: merino against the skin, synthetic over it.

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Marta Gabarda — merino wool and silk underwear from Sofia, Bulgaria. Order at martagabarda.com or by phone, delivered by Econt with cash on delivery.

You can see and feel merino wool underwear in Sofia at the Marta Gabarda atelier, 205 Alexander Stamboliyski Blvd, Razsadnika district. Try the fit, check the fabric weight by hand and buy on the spot. Visits are by appointment. For hikers, this removes sizing guesswork and return shipping.

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Why visit when I can just order online?

Because merino underwear is one of the few products where a photo tells you almost nothing.

Two items can look identical on screen and behave completely differently against the skin. The difference lies in the fabric weight, the knit, and whether there is silk in the blend. None of those are visible in a product image.

What five minutes in person actually tells you:

• How thin it really is — most people expect something like thermal gear and are surprised it is thinner than a T-shirt.
• Whether it itches you — the most common fear about wool. The answer is personal to your skin, not statistical.
• How it sits on the body — especially important for bralettes, bodysuits and boxer-style shorts.
• The difference between models — 100% merino and a merino-silk blend feel noticeably different.
• The true colour — screens lie, particularly with melange shades and browns.

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What does a hiker specifically gain from visiting?

Hikers ask more specific questions than the average shopper, and those are exactly the ones that are hard to resolve online.

Getting the size right the first time

A base layer needs to sit close to the skin to work. Too loose and the merino cannot manage moisture. Too tight and it chafes under backpack straps.

Trying it on takes a few minutes and settles a question that otherwise costs you a return shipment.

Checking the friction zones

Bring your backpack. Seriously — this is the most practical advice in this article.

With the pack on, you can immediately see where the shoulder straps cross the seams and whether anything bunches exactly where you will be carrying 12 kilos for six hours. For women this is the deciding factor between a bralette and a conventional model.

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Is it a shop or an atelier?

An atelier and showroom, not a retail store. That distinction is what makes the visit worthwhile.

Marta Gabarda is a family business and the merino wool underwear sold in Sofia is sewn right here, on site. You are not meeting a sales assistant — you are meeting the people who make the product. You can ask why the blend is 70% merino and 30% silk, why some items have no side seams, and what happens if something comes apart after two years.

In practice this also means the stock on site does not always match the full online catalogue. That is why calling ahead is not a formality.

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Where exactly is the atelier?

Address: 205 Alexander Stamboliyski Blvd, Sofia — Razsadnika-Konyovitsa, Krasna Polyana district.

In Cyrillic, for taxi drivers and delivery apps: бул. „Александър Стамболийски” 205, София. Save it as an image or a note — most local drivers will find it instantly from the Cyrillic, less so from the transliteration.
By public transport:

• Metro: the nearest station is Konstantin Velichkov. From there it is a few minutes’ walk south to the boulevard.
• Tram: Alexander Stamboliyski Blvd is the main tram corridor between the centre and the western districts. Get off at the stop by the junction with Konstantin Velichkov Blvd.
  Landmark: the National Palace of Children sits right at that junction. Once you see it, you are in the right place — the atelier is a little further along the boulevard.

Tram routes along Stamboliyski changed in 2026 after the boulevard was rebuilt, so check the current line number with the Sofia Urban Mobility Centre or Google Maps on the day you travel.

By car

• The boulevard is open in both directions following the roadworks.
• Street parking is available on the side streets behind the boulevard and usually fills less quickly than in the centre.
• Coming from the centre, simply drive west along Stamboliyski; the street numbers increase in that direction.

Opening hours

• Monday to Friday: 10:00 – 17:00
  
• Closed Saturday and Sunday

Before you set off

• Call: +359 878 876 524 (Jordan) or +359 878 540 550 (Yana)
• Or email: office@martagabarda.com
• Visits are by appointment — that way someone is free to meet you and the model you are interested in is on site.

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What should you bring?

• Your backpack, if you are buying for hiking — the reason is explained above.
• A garment you would wear over the base layer, to check whether it shows through.
• Your size in other brands, as a starting point.
• A specific question — “what will you use it for” is the single most useful thing you can tell us.

If you want to arrive prepared, browse the full merino range and read how wool underwear actually works beforehand, so you know what to ask on the day.

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How do you pay in person?

Online orders are cash on delivery, but when you visit you pay directly and take the item with you. No shipping cost and no waiting for a courier. We accept card payments

That is also the practical reason a visit works out cheaper: you save the delivery fee, and if you are unsure about sizing, the cost of a return as well. Buying merino wool underwear in Sofia in person is the fastest way to get the right size first time.

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Frequently asked questions

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Marta Gabarda — a family workshop making merino wool and silk underwear in Sofia. 205 Alexander Stamboliyski Blvd · +359 878 876 524 · office@martagabarda.com

Yes, wool underwear works in summer. Merino is thin, breathable and cooling: it pulls sweat away from the skin, dries quickly and does not smell after days on the trail. For hikers that means less luggage, fewer blisters and a drier back on the climb. The key is fabric weight — summer merino is around 150 g/m².

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Why does wool make sense in summer at all?

Most people associate wool with winter because they have only met it as a thick jumper or an old thermal set. Summer merino underwear is a different product — a fine knit with the thickness of a T-shirt, weighing less than a pair of socks. The material does not warm you on its own. It regulates temperature by managing the moisture around your skin.

What is the difference between merino and ordinary wool?

Merino wool comes from a sheep breed with an exceptionally fine fibre — around 17–19 microns, against 25–40 microns for conventional wool. The finer fibre bends on contact with skin instead of pricking it. That is why merino does not scratch and can be worn directly against the body with nothing underneath.

How does merino actually cool you?

Merino absorbs moisture into the fibre structure and releases it through evaporation. That process draws heat away from the skin and works like a slow, constant air conditioner. The knit also traps air, which insulates the body from outside heat — the same principle behind covered clothing in desert climates.

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What does a hiker gain from merino underwear?

On a day walk the difference is pleasant. On a multi-day trek it becomes functional, and sometimes a safety matter.

• Two-way temperature regulation — cool on an exposed climb, warm when you stop on a ridge where wind makes it 10 degrees colder.
• It does not smell — lanolin and fibre structure suppress the bacteria that produce odour. Realistically: three days without washing, no social problem in a mountain hut.
• Warm when wet — merino keeps part of its insulation even damp, unlike cotton.
• Fewer blisters and chafing — dry skin under a pack and between the thighs rubs raw far more slowly.
• Lighter pack — one set instead of three saves weight and space on a long trek.
• Spark resistant — wool does not melt and is slow to burn, which matters near a fire or a gas stove.

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Why is cotton a bad choice in the mountains?

Cotton absorbs up to 27 times its weight in water and does not release it. Once soaked with sweat it stays wet for hours and strips body heat through evaporation — precisely when your body needs that heat most.

Hikers have a saying: cotton kills. It is not dramatic for effect. The classic scenario looks like this: you sweat hard on the climb, reach the ridge, the wind picks up, the temperature drops 8–10 degrees, and a wet cotton shirt cools you toward hypothermia in twenty minutes — even in July.

Merino or synthetic — which is better for summer?

Both beat cotton. The choice depends on trip length and on what bothers you most.

Merino wins when:

• You are out for several days with no chance to wash
• Temperatures swing widely — hot in the valley, windy on the ridge
• You have sensitive skin that reacts to synthetics
• You will sleep in the same set in a hut or tent

Synthetic wins when:

• The activity is short and very intense
• Low cost and abrasion resistance matter most
• You do not care about odour after four hours

A common compromise many hikers use: merino as the base layer against the skin, with a synthetic or softshell second layer over it.

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What fabric weight should I choose for summer?

Fabric weight (g/m²) matters more than the brand name.

• 120–150 g/m² — summer weight. For hikes from May to September, heat at lower altitude and moderate elevation.
• 180–200 g/m² — all-round. Works from spring through late autumn and for a night in a hut.
• 250 g/m² and above — winter thermals. Overkill in summer; it will overheat you.

Practical rule: for a July ascent, take summer-weight underwear and add a light fleece or windbreaker for the ridge, rather than carrying heavier base layers.

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Why blend merino with silk?

Pure merino is excellent, but fine summer knits are delicate. Silk threads add strength and a smooth, cool hand feel that makes the fabric more comfortable in direct contact with skin.

A 70% merino / 30% silk blend is a classic summer base layer:

• Silk is naturally cooling and adds almost no bulk or weight.
• The fabric becomes softer and glides over skin instead of clinging when you sweat.
• The blend resists stretching better than 100% fine merino at the same weight.

This is the exact composition we use at Marta Gabarda for the wire-free summer bralette — 70% merino, 30% silk, around €19. We are a small family workshop in Sofia, and the whole range is underwear rather than technical sportswear, which is why the focus is on how fabric behaves against skin over many hours.

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How do I choose for a specific route?

A day hike on Vitosha (Cherni Vrah)

You set off in heat and meet wind at the summit. A light merino top or bralette and merino briefs are enough. The main gain is not standing on the peak in a soaked shirt.

A two-day trek in Rila (Seven Lakes or Musala)

A hut overnight and a 15-degree swing between midday and dawn. One set of summer merino covers both days — you wear it at night in the sleeping bag too, where it adds an extra insulating layer.

A multi-day trek (a section of Kom–Emine)
This is where merino shows its real value. Two sets cover five or six days: one worn, one airing on the pack. Merino recovers from odour with a few hours hanging in fresh air.

Specific considerations for women
On a multi-day trek, pack straps run exactly through the underwire zone. So:

• Choose a wire-free, unpadded bralette — no hard pressure point under the shoulder strap.
• Look for flat seams in the underbust area.
• Avoid synthetic lace in friction zones.

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How do I care for merino underwear?

Merino is usually ruined by washing, not by wearing

• Wash at 30 °C on a wool cycle, or by hand.
• Use enzyme-free wool detergent — standard powders break down the fibre.
• No fabric softener — it coats the fibre and kills breathability and odour resistance.
• No tumble dryer, and do not hang wet merino on a hanger — dry it flat so it does not stretch.
• Between washes, simply air it out — enough in about 80% of cases.

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Frequently asked questions

Isn’t it too hot to wear wool in July?

Not at summer weight (120–150 g/m²). Summer merino is thinner than most cotton T-shirts and actively cools through moisture evaporation. The sensation is dryness, not warmth.

Does merino itch?

Fine merino (17–19 microns) does not itch for most people, because the fibre is soft enough to bend on contact with skin rather than prick it. People who remember wool as itchy were usually wearing coarse 30+ micron wool.

Does merino really not smell after several days?

Yes, this is one of its best-documented properties. Wool fibre absorbs odour into its core and limits the environment bacteria need. After three or four days on the trail, merino smells noticeably less than synthetic does after one.

Can I wear merino directly against my skin?

Yes, that is exactly what it is for. Merino works best as a base layer in direct skin contact, because that is where it manages moisture. Wearing a cotton shirt underneath removes almost all of its advantage.

How quickly does merino dry?
More slowly than pure synthetic, faster than cotton — usually a few hours when aired. The important difference is that merino keeps warming you while damp, so drying speed matters less.

Bralette or bra for a woman carrying a pack?

A wire-free bralette. Rigid underwire creates a pressure point exactly under the pack straps and causes pain and chafing on long days. A wire-free merino bralette solves both the pressure and the underbust sweating at once.

Is it worth the price?

Is it worth the price?

Merino costs more per item but replaces several sets on a multi-day trek and lasts years with proper care. For hikers the maths usually works out, because you buy one or two sets rather than ten.

Where can I buy merino underwear in Bulgaria?
Marta Gabarda ships merino and silk underwear across the country with Econt, with cash on delivery. Order online at martagabarda.com or by phone. The atelier is at 205 Alexander Stamboliyski Blvd in Sofia, Monday to Friday, 10:00–17:00.

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In short

• Wool underwear works in summer at fine merino weights of 120–150 g/m².
• Merino cools by managing moisture, it does not simply add warmth.
• Cotton is the worst choice for the mountains — wet, it strips body heat.
• A 70% merino / 30% silk blend adds coolness, smoothness and durability in a summer base layer.
• For women carrying a pack, a wire-free bralette is the more practical choice.

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Marta Gabarda — merino wool and silk underwear made in Sofia, Bulgaria. Questions: office@martagabarda.com