Merino or Synthetic Underwear? A Comparison

The right thermal underwear improves thermal comfort, convenience, and proper sweat management during outdoor activities. This is important both for winter mountain trekking and summer cycling. Find out which is the better choice – merino or synthetic – and choose the material that suits the season and type of activity.

What properties does merino wool underwear have?

Merino wool has an extraordinary ability to regulate body temperature. This allows it to provide excellent thermal insulation in winter and wick away moisture in summer.

Merino wool fibers are thin, soft, and flexible, which means the clothes don't irritate the skin and can be worn in direct contact with the body. They're also suitable for people with very sensitive skin.

Another advantage of merino wool is its ability to absorb moisture – merino can absorb even significant amounts of sweat without feeling wet. Quick moisture wicking is a crucial feature, especially during physical activity. The material's antibacterial properties also ensure that thermal underwear containing wool stays fresh for longer and requires less frequent washing.

What are the features of synthetic thermal underwear?

Underwear made of synthetic materials such as polyester, polyamide, or elastane wicks moisture away and dries quickly. This makes it ideal for intense exercise, ensuring your body stays dry.

Another advantage is the material's flexibility and impressive abrasion resistance. Synthetic fibers also retain their original shape even after frequent use and washing. It's also important that Women's or men's thermal underwear made of synthetic fibers is usually cheaper than models made of merino wool.

When is merino wool thermal underwear better?

Merino wool thermal underwear is perfect for outdoor activities in low temperatures. Choose merino wool thermal underwear for the following situations:

while practicing winter sports,
during long walks and trekking,
if you have sensitive skin,
when you value natural and breathable fibers,
when traveling when you don't have the opportunity to wash your clothes often.

When is underwear made of synthetic fibers better?

Thermal underwear made of synthetic fibers is the perfect solution if you plan to engage in intense physical activity and also want immediate moisture wicking and lightweight fabric. Synthetic underwear is perfect for:

running and interval training,
cycling,
indoor sports and fitness,
short and intense trekking in the mountains – especially in spring and summer.

What is the best thermal underwear depending on the season?

Find out which men's or women's thermal underwear will work best and will feel like a second skin, depending on the season.

Spring is characterized by unpredictable weather, so temperatures can fluctuate significantly throughout the day. Merino wool is a good option, as it adapts to temperature changes. However, if you plan to train intensively, synthetic clothing is an alternative option.
Summer – at higher temperatures, synthetic thermal underwear will be the best solution, as it ensures dry skin, dries quickly and wicks away sweat almost immediately.
In the fall, reach for a merino wool T-shirt, which is soft to the touch and provides thermal comfort even when damp. Choose synthetic underwear for activities of both high and low intensity.
Winter – synthetics are perfect as a first layer during intense workouts. Merino wool, on the other hand, is an essential wardrobe staple for skiing, snowboarding, and trekking.

What are the disadvantages of merino wool?

Merino wool is less elastic than polypropylene or polyester underwear, so it may limit your freedom of movement when practicing certain sports.

What are the disadvantages of wool? The most important of them include:

higher price compared to synthetics,
less abrasion resistance,
slower drying compared to synthetic clothes,
the need to take greater care of clothes, washing at lower temperatures and using special programs.

What are the disadvantages of synthetic underwear?

Synthetic thermal underwear may not be suitable for people with sensitive skin because it does not have the same delicate structure as natural fibers.

What are the disadvantages of synthetic underwear? These include:

tendency to absorb and retain odors more quickly;
less thermal comfort when the weather changes frequently;
greater susceptibility to static electricity in clothes,
feeling cold in high humidity.

What thermal underwear is best for intense activity?

During high-intensity exercise, rapid sweat wicking and lightweight fabric are paramount. Therefore, synthetic thermal underwear may be a better option – it ensures freedom of movement, dryness, and comfort.

Underwear made of synthetic fibers is perfect for long-distance runs, cardio and interval training.

What about people who engage in outdoor sports, for example, in winter? In such a case, opt for merino wool underwear, as it effectively retains heat and ensures thermal comfort. Modern thermal underwear combining both materials can also be an optimal solution. This hybrid underwear combines the benefits of both synthetic fibers and wool.

If you regularly exercise outdoors or at the gym, you should have merino and synthetic underwear in your wardrobe. This will allow you to easily match your outfit to the weather, season, and intensity of your physical activity. This will ensure maximum thermal comfort and effectively reduce the risk of overheating or catching a cold.

Written by Sportowy Butik