The Ultimate Base Layer Guide - Get to know your outdoor fabrics
- carlypadrta
- Feb 1, 2024
- 8 min read
The ULTIMATE guide to Base Layers
Get to know your outdoor fabrics
My names Carly – I am an all-around outdoorsy person living full-time in the gorgeous state of Alaska. If you are reading this chances are you are interested in knowing more about base layers, their benefits, and what to avoid when buying. Living in state with extreme temperature fluctuations I have learned firsthand the benefits that wearing the appropriate layers make while out in the field.
Here is my guide to base layers – I have included basic knowledge of the common fabrics base layers are made from, my experience and opinions, as well as brands to check out. Unlike other "guides" I am not including a bunch of links and saying "buy this" -why? most of the time those links are fully sponsored and are getting paid to be there. I want to help you make the best informed decision possible when it comes to choosing your base layers.
WHAT IS A BASE LAYER:
A base layer is a next to skin garment with the main purpose of helping the body regulate its temperature by being moisture wicking (moving moisture away from the body and to the garment). These garments are normally form fitting to help prevent cold air from circulating next to the skin. They can also have an insulating component to add extra warmth in cold conditions.
IMPORTANCE OF WEARING BASE LAYERS:
A solid base layer can make or break an experience. Being in Alaska our winters can be harsh – that does not mean we spend all winter indoors though. The appropriate base layer can help keep an individual feeling comfortable AND safe. Even if your climate is milder, there is still an added benefit to wearing the appropriate layers. Some of the benefits of a great base layer includes:
- added insulation
- lessening the risk to chaffing and blisters
- keeping moisture away from the body
- lessening the risk to hypothermia
- feeling less “clammy”
Depending on the fiber, there are other potential beneficial characteristic a base layer might have. Next, I have listed a few of the more common base layer fabrics and the pros & cons of each.
WHAT TYPE OF MATERIALS TO WEAR & AVOID
Synthetics
Synthetic base layers are one of the more common types to find. These include fabrics like polyester, nylon, fleece, and spandex. These fabrics are common for sportswear – think basketball shorts, leggings, and running apparel. They are derived from petrochemicals (i.e. crude oil).
PRO: Synthetic base layers are a more budget friendly option, they are widely available, and are less prone to causing irritation for people with sensitive skin. They are also excellent at being moisture wicking and dry much faster than cotton.
CON: One of the biggest downsides to synthetic garments is they are generally not antimicrobial and can cause odor over time. They also do not have similar insulating factors as other fibers like merino wool.
Another major issue to be aware of when choosing a synthetic fiber is the use of PFAS (per- and polyfluoroalkl substance), also known as “forever chemicals”. These chemicals can be found in clothing because of their water and grease resistance properties. Unfortunately, they also build up in our bodies and can interfere with our endocrine system. Many outdoor brands are moving away from using PFAS-6 in the manufacturing of their garment. I am no expert and want to do more homework myself on the effects of PFAS-6 and I would strongly encourage the reader to do the same.
Brands I know moving away from the use of PFAS-6
- REI brands *
- STIO *
STIO discount code: CARLY20
Silver (and other mineral additives)
Some synthetics like ones made with the proprietary Sterling™ fabric use the antimicrobial properties of silver to help with the odor issue synthetics face. I have a base layer top and bottom both made with Sterling™ and have put it to the test a multiple time. I spent 5 days camping with the base layer set – wearing them every day. After day 5 the layers had no noticeable odor even after wearing them hiking.
The company Alpine Fit is where I got my Sterling™ base layers – Their garments are made in the USA (Alaska).
Another common mineral additive I have seen is the use of zinc. The brand FORLOH uses zinc with their base layers. I haven’t used their base layers, but I do have other items from this brand and enjoy them.
Brands to consider
FORLOH discount code: CARLYONTHEKENAI
Merino (and other wools)
The backcountry beloved MERINO! Merino wool is harvested from a specific breed of sheep known as, believe it or not, Merino sheep. Ok -maybe that is not surprising.
PRO: This is an all-time favorite of mine – it is moisture wicking, antimicrobial (meaning odor resistant), soft and temperature regulating. I wear merino EVERY DAY. It has been my go-to for extreme cold days in the backcountry for many years. Another fantastic factor to merino is it is sustainable – merino (and wool in general) is natural, biodegradable, and renewable.
CON: Merino is usually expensive and not very durable - purchasing a blend ratio can help with this. Merino can also cause skin irritation for some individuals for (usually) either of the two reasons:
1. Merino naturally has lanolin and can trigger an allergy for individuals with a sensitivity to lanolin.
2. It is possibly a low-quality merino. Merino gets graded based on the diameter of the fibers ranging from ‘broad’ to ‘ultrafine’. Ultrafine being the most luxurious and softest fibers while broad is coarser and can be itchier to wear for someone with sensitive skin.
Merino Vs. wool
There is also a big difference between merino wool and just wool. This can cause some confusion when purchasing wool products. Wool on the other hand is a generic term used for animal fibers that can be anything from sheep, goat, yak, buffalo etc. When purchasing wool, it is important to know what animal it is since not all wool is equal.
Wool Notes:
If merino wool irritates your skin:
- Check the fiber content. Sometimes blends are less irritating on skin. If it is the lanolin causing skin irritation, then try alpaca! Garments made from alpaca fibers are not as common as merino but is becoming more easier to find commercially. Alpaca also does not have naturally occurring lanolin, so it is a safer bet for anyone with a lanolin sensitivity.
Quality + Ethically Sourced
- Before purchasing always check if the brand is Woolmark certified and from non-mulesed sheep. I deeply want to encourage the support of brands that source their wool humanely.
Beware of ratios
- Usually, merino layers will still come as a merino + synthetic blend. This has many advantages including added stretch, durability, and usually a cheaper price tag for the garment. I always caution others to check the blend ratio before purchasing – I usually won’t go for less than 50% merino.
Brands to consider for merino
- Alpine Fit (USA made)
- Duckworth (USA made)
- Wuru (USA made)
- Woolx
Other Wools:
As mentioned, some other wools that can been found are alpaca, yak, buffalo, other types of sheep, and goat. These are less common to find but yak and alpaca are starting to increase in popularity. I have personally used alpaca (socks) and the material is very comparable to merino but a bit softer. The alpaca socks I have tried haven't been as durable as merino - this could be due to different blends being used.
Brands to consider
- Hollow Socks offer alpaca socks
Bamboo (and cellulose sources)
Aka - the Rayon Family
Another fabric choice that is gaining popularity is bamboo and other pulp-based fabrics. Plants such as eucalyptus, pine, or beech are commonly used and are considered a semi-synthetic fabric because of the complex processes it takes to turn the pulp to fabric. This process is a mix of mechanical and chemical in nature and will get marketed under different fabric names depending. Fabrics names that are commonly found for these plant-based options are rayon, viscose, modal, and lyocell – there are other proprietary names that are used in the industry.
It is important to know that not all of these fabrics will operate the same as they are not all created equally.
PRO: They are made from regenerative sources like bamboo. Overall, the fabrics are moisture wicking and soft – rayon was originally created as a silk alternative. It is also resistant to odor.
CON: Most of the fabrics are highly dependent on chemicals like sodium hydroxide in their manufacturing process - there are a few fabric exceptions to this. The process to create these fabrics do have environmental and ethical workplace concerns. Rayon can take longer to dry when fully saturated. Pilling of the material is also common in cheaper rayon sources (modal is the exception to this because of an additional mechanical step it undergoes). Overall, knowing what the base layer fabric is made of can be tricky to determine
Viscose vs. Modal vs. Lyocell vs. Tencel®
Viscose/Rayon: This fabric is cheaper to make and less environmentally sustainable due to its use of sodium hydroxide. It is also more prone to pilling.
Modal: Like viscose but goes through an additional mechanical stretching process that helps with pilling. This fabric is commonly found in swim and other sports wear.
Lyocell: This version uses an organic solvent known as N-Methylmorpholine N-oxide(NMMO) instead of sodium hydroxide. The solvent used is easier to filter and reuse in a “close loop” cycle making the production of it more environmentally friendly.
Tencel®: This one is a lyocell brand, but commonly found in outdoor apparel so it deserves a mention. The fabric comes from eucalyptus trees. The internal structure of the fiber is a bit different resulting in improved ability to absorb water.
Overall – if the base layer brand is not specifying which fabric it is using, I would avoid. Also, given that fabrics from the rayon take longer to dry out, I would also avoid in wetter climates. Their use can be more applicable in more mild and dry ciliates.
Cotton
Cotton in the outdoors is an absolute “no” – regardless of if the weather is great or not. Why though? Cotton will absorb AND retain water. This can cause skin irritations like blistering and chafing or in cold conditions increase the risk of hypothermia. Beyond that it is also not antimicrobial and will develop a funky smell overtime.
I have made this mistake on more than one occasion by wearing cotton blend socks and shirts. I have badly blistered my feet over the years, on even short hikes, by making this mistake and want to caution anyone and everyone from also doing it.
But, what if you’re new to the outdoors and don’t have gear yet?
Instead of wearing cotton “street clothes” (i.e., jeans and your favorite t-shirt) think about repurposing your gym and/or sportswear. I often wear my gym leggings (commonly a blend of different synthetic material) as a base layer. Not only are they made of moisture wicking material, but it also helps to save money initially.
There is a caveat to this – most authentic socks are a cotton blend. Many of the larger merino wool companies have socks that are priced from $15 to $30 USD – and that will be one of the BEST investments any outdoors person can make.
PRO TIP: Darn Tough Socks normally runs a BOGO for black Friday – they also have a lifetime guarantee and made in the USA. I have personally used their warranty on socks, and it was a very simple process.
So, What's the best base layer?
In reality - there isn't one. I am a huge fan of merino and that is my personal recommendation when choosing a fabric. From there I focus on quality of the garment, where it is made, and how good the company's customer service is (I am all for companies who "make it right" - but at minimum, respond to emails). Listed through the guide are all the companies I have personally used and feel comfortable recommending to others.
To wrap this up - if you have found this helpful, please feel free to share on your social media and on Instagram tag @Carly_on_the_kenai. Also, reach out with any questions that do occur.
*The only links listed that I am an affiliate for are Stio and REI - I make a small commission if you purchase through my links *
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