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What is a base layer?

Which Base Layer - A Buyers Guide

Base Layers, sometimes referred to as Foundation or Primary Layers, form the basis of any clothing layering system. Designed to sit next to the skin and "Wick" sweat away to provide a dry "Thermally Regulated" result. They are not just for the cold weather as many people think.

By wicking moisture from the skin, a Base Layer will help keep you warm or cool depending on the fabrication but ultimately "thermally regulated" to achieve that Goldilocks result regardless of the conditions.

There are very significant differences between fabrics on the market but it is essential that you get a fabric that works with your body. Slapping on a thin 100% Lycra "skin" that has no technical properties, will ultimately be counter-productive compared to a warm thermal fibre brushed fleece material. holds a wide selection of top brand name base layers made from a variety of fabrics for every condition and requirement you may have.

This guide is designed to provide you with every option you might experience to ensure you get the item you need.

Garment Choice:

Choose the one that works for you.  All the technical fabrics we have within our range have various features and benefits and each has its own merits but critically, you should look for four primary fabric Considerations:

  • Wicking: Does the fabric wick effectively?
  • Fit: Does the garment fit you and is comfortable next to your skin
  • Seams: Does it have a seamless structure or flat locked seams that won't rub
  • Odour Control: Being next to the skin, does the fabric have natural or man-made anti bacterial properties that will absorb or eliminate fabric odours occurring
  • Durable: Is the fabric durable enough for the function you are looking for.
  • Avoid Cotton: Cotton retains moisture for a long time and doesn't seek to move it away from the body.  Cotton is a killer when it comes to base layers.


Merino Wool

Merino wool is the result of millions of years of R&D by Mother Nature herself. Rich in natural properties that inspire some of the worlds' leading brands, its unique properties enable it to be manufactured into a wide range of luxuriously soft and stylish clothing with some key benefits. 

Merino is ethical, soft and has Natural Odour Prevention properties as well as very effective thermal properties that can also be combined with synthetics for additional durability and performance. Basically, the heavier the weight per Square Metre (GSM) the warmer the garment but equally the more expensive. For a real in depth analysis of Merino Wool, click here and read at your leisure.


Polyester is a very clever technical fibre.  Strong, highly efficient at managing moisture, resistant to stretching and very durable making it an ideal fabric for use in base layers as they ensure garments remain close fitting as intended.

  • Moisture Wicking: Polyester has exceptional wicking capabilities and is very fast drying. Many brand names are affiliated to Polyester including CoolMax™, ThermoCool™ and DriFit™
  • Odour Resistant: Whilst not possessing any "natural" fabric odour defence like Merino and Silk, a decent Polyester base layer is usually combined with some technical wizardry that prevents bacteria infesting the fabric that can cause fabric odours occurring. In-built chemical treatments at production and the use of Silver Ions both resist the bacteria that can cause fabric odours.


Another natural fibre of course and one that many use in warmer conditions but equally effective in cold conditions.  Silk has many of the properties of Merino Wool but the fibres are even finer that wool so can be woven into incredibly fine garments and is therefore often preferred next to skin ahead of wool.  But as a general rule, Silk is not as effectively thermally efficient as wool but does have many positive attributes.  Moisture wicking, natural anti bacterial resistant, super soft, easy wash and no ironing are all positives to considering Silk for your base layer.


    Another synthetic fabric that has evolved brilliantly as fabric technologies have advanced.  Polypro is the thermal king of synthetics constructed using long strings of lightweight hollow fibre and is exceptionally thin so can be woven into almost any shape and finish desired.

    Polypropylene is hates water.  As a result it acts continuously as a conduit for moisture rather like an ultra-fine straw so it moves sweat and moisture very fast indeed.  This means that Polypro garments keep you dry as well as warm.  A good example of a fast dry fabric is the Helly Hansen LIFA product, regarded by many as the best example of a stay dry base layer.

    Polypro like Polyester is also very durable so is ideal as a fibre within a base layer.  Again a good Polypro garment will have integrated anti-bacterial treatments in the same way as Polyester to eradicate bacteria that can cause fabric odours.

    Fitting, Design & Season

    A base layer will either be a compression fit or fitted design.  A loose fitting base layer isn't really a "base layer" so to speak, it's a t-shirt worn next to the skin but still acts as a wicking layer. They don't have to fit too tightly but do consider they kind of need to hug a bit.

    Base layers aren't necessarily just for the cold. A quality base layer should be the basis of any layering system and can be used in every season. A thermal base layer will provide added warmth. A specific base layer light in construction, offers a cooling effect and prevent uncomfortable moisture build up in warm conditions as well as defending against harmful sun's rays. Think about that bead of sweat rolling down your back in the height of summer... Exactly! Summer specific and winter specific base layers have distinct differences in fit, design and appearance.

    Summer Base Layers:

    Summer base layers focus primarily on wicking away sweat or "managing" moisture, to prevent an uncomfortable build up of perspiration on the skin. These base layers are made of extremely thin, light fabric or can even be mesh. Wearing a base layer underneath your kit even in the summer can stop uncomfortable thigh chafing, nipple rub and sore arm pits and stops your workout gear or work clothing, becoming damp with sweat.

    Summer Base Layers can be Compression Fit or Fitted depending on the brand, the material and the objective required as well as the desired fit.  Long Sleeved, Short Sleeved, Shorts or Leggings are amongst the choices for a Summer use base layers and synthetic and wool are both desirable fabrics

    Spring/Autumn Base Layers

    These base layers are for the "transition" seasons and therefore resemble a compromise between sweat management and thermal warmth. These can be a slightly thicker fabric and a combination of Polyester & Polypro, Merino Blend or 100% Merino Wool.  Some brands now combine the obvious benefits of Merino Wool with Synthetics to get the best of both worlds such as Helly Hansen®, Artilect®, TriDri® and ODLO®.

    Again, Spring/Autumn Base Layers can come in Compression and Fitted designs depending on what each individual desires and can be long sleeve, short sleeve or shorts or tights.

    Winter Base Layers

    The most popular of the Base Layer family and the reason most people elect to wear stay warm!

    Winter Base Layers focus on keeping the "core" of your body warm.  If the "core" or torso is kept warm, then the rest of the body is easier to keep warm.

    Consider your "core" as the boiler and your hands and feet as the radiators to use a heating system analogy.

    If the "boiler" is hot, then the radiators are hot.  If you insulate the boiler and the radiators, then that valuable heat is retained.  Warm "core" = warm hands and feet.

    Winter Base layers can come in a variety of fittings from Compression to Fitted and some tops have thumb holes to provide coverage to the hands if desired.

    Made from a variety and usually a combination of, Wool, Polyester and Polypropylene, different brands adopt different methods to ensure your thermal comfort.


    How do you decide what you need? There is no one base layer that does all things despite some manufacturer's claims to the contrary.

    You ideally need a base layer for each season to ensure maximum comfort with increased warmth in winter and the benefits of wicking materials, to dissipate perspiration, in the warmer months. Having a good base layer can significantly improve your comfort and enjoyment for all seasons and all sports and leisure activities.

    The fabric you choose will depend on your budget, your tastes, preferences, what you intend to use the product for and even allergies. Merino wool is normally more expensive than synthetics due to the expense of sourcing the relatively rare natural material. However, it may be worth spending more on merino if you are going to be using it frequently for commuting or walking when you will value the natural odour resistant properties and soft feel as well as the thermal properties.

    As a general rule for more dynamic contact sports such as Football or Rugby, a synthetic based garment is more durable and more easily washed of mud and grass stains so check out our Field Sports Base Layers.  For Skiing, Cycling and Hiking there is a wider choice and Merino is equally at home under your ski wear as are synthetic fibres.  There are also numerous brands that combine synthetic fibres with Merino to offer you the best of both worlds.

    It is also important to ensure you get a base layer that fits you well; base layers are designed to be a "second skin" therefore a close fitting profile is more beneficial. Sizes vary between manufacturers, so check the Size Guide on individual products that you buy.

    Finally, you can always call. has many years experience in this field and can advise without bias on the ideal solution for your needs.  We're here to help: 01689 603675.

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