How to Choose your Underwear (Base Layer) for the outdoors

Do you ever get uncomfortable while outdoors adventuring? Do you get chaffing, dampness, and general discomfort? If you’re wearing traditional underwear, it might be time to change to a base layer more suited to your activity.

A lot of underwear is made from cotton and cotton retains perspiration and can leave you feeling chilled, wet, clammy and sore. If you’re wearing cotton, ditch it and get something made from materials that treat you better and makes the whole experience a more comfortable one. Start looking at some of the modern synthetic fabrics, silk or merino wool as baselayer options.

Moisture wicking underwear dries must faster than cotton underwear, it helps transport perspiration away from your skin and it helps moderate body temperature so that you’re not boiling one minute and freezing the next, this, in turn, keeps you safer when outdoors.


Underwear you can use for outdoor use is from briefs to T-shirts to long underwear tops and bottoms. They can be designed to fit loosely or snugly.

Fabrics for Underwear


Silk is best in cool weather and when carrying out moderate to low-intensity activities.

When the label says it’s been ‘Treated’ it means the silk has been changed with chemicals to aid it’s wicking properties. Silk is generally less effective at wicking moisture away from your skin but it does provide a luxurious and soft feel as well as having very low bulk.

You do need to keep your silk undies regularly washed because they will smell quicker than say synthetics, you need to look at the washing instructions before you buy as some garments need hand washing, some are fine in the washing machine, although Silk can shrink when washed like this.

Silk has been around a long time, first invented in China 3630BC and it’s still in use today, that tells you something about this great material.


Merino Wool

Merino can be worn in best in cool conditions and for most activities, it’s warmer than Silk and Synthetic fabrics and it’s effective at helping regulate body temperature, it breathes really well and so it’s great as a wicking fabric and as an insulator for keeping you both warm or cold.


It also has antibacterial properties allowing for it to be worn for longer than the other fabrics as it does not build up odors easily, it’s often harder to wash and it dries slower than other fabrics, in our opinion though it’s one of the best fabrics to use, if you can afford it.

The human hair is the bigger one.


Synthetic fabrics are fast drying, good wicking and work well in most conditions and in most activities. They’re good at odor resistance, although not as good as the Merino Wool.


There’s a huge range of synthetic fabrics, they’re nearly always a blend of different materials, polyester, rayon, spandex, nylon, polypropylene are all common.

These fabrics are usually light and soft, easy to care for and are wrinkle resistant. They can be stretchy if they include materials like spandex, this can make for a much more comfortable fit.

How your underwear should fit

With conditions that are warmer, the looser your underwear is the more comfortable it’s going to be. In cooler conditions, snug-fitting underwear is the best choice, keeping the warmth generated by your body close to your skin.

Underwear Fabric Weight

Here are some general guidelines for picking the weight of your underwear.

  • Heavyweight: Cold, windy conditions.
  • Midweight: Cold to moderately cold conditions.
  • Lightweight: Moderate to cool conditions.
  • Ultra lightweight (micro-weight): Best for cool and mild conditions.

Ultimately you need to pick underwear that’s going to best fulfill your requirements based on your activity and body type, always be aware that the conditions outdoors can change quickly and wear something that can accommodate this or take a different baselayer with you to change into if needed.



Outdoor Revival – Reconnecting you to the Outdoors


fmssolution is one of the authors writing for Outdoor Revival