Base layer & thermal underwear guide 

Odlo base layers meet the needs of all types of everyday athletes. To choose the right base layer, think about the intensity level of your activity.

For high-intensity activities, our Performance and Natural Performance base layers are the obvious choice. They’re great at wicking moisture away from your skin and help to regulate your body temperature while running, skiing and beyond.

Our Active and Natural Active collection is designed for low- to medium-intensity activities. These base layers deliver ultra-lightweight comfort, durability and freedom of movement for anything from leisurely city strolls to casual hikes.

You can buy Odlo base layers in two different fits:

• Slim: Our slim fit garments have a slender cut for a next-to-skin fit. For a looser fit, we suggest sizing up.
• Fitted: Our fitted apparel is made to fit your body, but has a slightly looser cut than our slim fit garments. You can go for your usual size.

As a rule, base layers should be close-fitting. It's best to try out which fit feels right, suits your chosen activity and intensity level and offers you the greatest range of motion and maximum comfort.

All bodies are different. So are our favourite fits. You might prefer a base layer to be a little looser rather than super snug. You should also think about the type of sport, season, intensity level and the other layers you’ll be pairing it with. Every movement should feel good, and all of this will all affect your choice for the right base layer.

If you want some guidance, check out the “what’s my size?” button on our product pages to get personalised sizing recommendations for your height, weight and age. You can also take a look at the sizing chart to find out which size matches your measurements for a particular product. Each product page has various features to help you work out the right size for your body type and preferred fit.

It sounds obvious to say that “seamless” refers to garments without any seams. But what does that actually do for you? Well, it means maximum comfort, no matter the activity or intensity level.

This unique construction method is what Odlo is known best for. It refers specifically to how a product is knit and then assembled. Often, everyday athletes explain the benefits of a seamless layer in terms of both comfort and performance. And because of the fit (next-to-skin), it is the optimal, most comfortable, highest performing base layer across almost all conditions and intensity levels.

With seamless, we also eliminate bulk, which makes it a great choice for apparel like boxers and panties because of its streamlined fit.

Each garment has its own care requirements, so make sure you always read the care label sewn into your Odlo product.

Here you’ll find some general care instructions that will help you maintain your Odlo product’s performance and make your garments last longer.

• Always wash garments inside out, especially if there are any prints.
• Fasten all zippers, buttons, Velcro, etc. to protect fabric during the wash.
• Use only mild liquid detergent, preferably with an eco-label.
• Try to stick to the recommended amount of detergent. If you use too much, it may not rinse out completely. This can affect the performance of your garments. Find out how hard the water is in your area, and use that to help determine how much detergent to use.
• Do not use bleach.
• Do not use fabric softeners. A win-win-win: cheaper for you, uses fewer chemicals and helps maintain the function of your garments.
• Do not machine dry your base layer. Most of our fabrics are fast drying and will hang dry in no time.
• Do not iron your base layer. Most of our fabrics are wrinkle-resistant. If necessary, iron your garments inside out, especially if they have prints.

More tips for eco-friendly textile care:

• Ask yourself if you really need to wash a garment or if you could just air it out or rinse out a stain instead.
• When it comes to merino wool, airing is better than washing to remove odours.
• Save on resources by loading your washing machine fully; don’t run it half empty.
• Care labels show the maximum temperature at which you should wash a garment. But to be more sustainable and also save on energy costs, we recommend washing base layers at 20 degrees with cold-water detergent.
• Donate your Odlo garments if you no longer need them. That way, other people can enjoy them or the fabric can be recycled.

“Base layers” are sometimes synonymous with “thermal underwear.” However, if you prefer for hygiene reasons, you can wear boxer shorts or panties underneath. For women, we also recommend a sports bra for optimum support. 

Base layers offer maximum comfort and regulate your body temperature. They can be adapted to different environments, duration and intensity levels of your activity. The fitted performance fabric wicks moisture away from your skin and warms, which means you’ll stay dry, comfortable and avoid any unpleasant itching, rubbing or chafing while working up a sweat.

The right Odlo base layer will fit like a second skin and act like natural climate control; the moisture wicking and fast dry time will keep you from freezing in winter and the breathability of the fibres will cool you down in summer.