You’ve probably heard about PFAS and BPA (aka forever chemicals) and how microplastics keep being found in our bodies. It all sounds – and is – bad, so switching to natural products is increasingly appealing. But where does natural underwear fit into the picture? Is some underwear “unnatural?”

What is natural underwear?

When we say “natural” we’re talking about fibers that come from the earth like Merino wool, Alpaca wool, cotton, silk and linen. We also include semisynthetic fibers in our definition, which are derived from naturally occurring fibers – like wood pulp being used to create Tencel Lyocell. All of these fibers are biodegradable and renewable.

Synthetic (non-natural) materials are basically plastics – polyester, nylon, acrylic, spandex, etc. Some underwear is fully synthetic, some is a blend of synthetic and natural fibers, and some is fully “natural.”

Our men’s and women’s underwear is 84% Merino wool, 12% nylon and 4% spandex. Our underwear fabric is corespun featuring our (m)Force Technology, where Merino wool is spun around a tiny, continuous nylon filament for added strength, stretch and recovery. This creates a longer lasting, higher performing underwear than one made with 100% Merino wool.

We’re always searching for new Merino wool technology that allows us to use an even higher amount of Merino wool in all of our garments. With the small amount of synthetic materials we use in our underwear, Merino wool is still against your skin (thanks to our corespun technique) and since wool is wrapped around a continuous nylon filament, microplastics aren’t an issue. We’ve also transitioned our latest underwear to a recycled nylon filament rather than virgin nylon, further reducing our environmental impact.

As with all things, going fully natural is best when possible, but any changes you make to have more natural fibers in your wardrobe is going to benefit you and benefit the planet.

If you’re not a fan of Merino wool or don’t need its performance and comfort benefits, you can also find great organic cotton, silk, hemp, bamboo and Tencel/Modal options out there that check the natural underwear box.

Why choose natural underwear

Natural underwear is better for your body.

It’s more breathable. Natural fibers allow your skin to breathe, which reduces the risk of rashes and infections (notably yeast infections for women). Your skin needs to breathe for your body to work well, whether you’re just hanging out at home on a hot day or pushing yourself on a long hike or run.

It’s often more comfortable. Natural fibers are less likely to cause skin irritation or allergic reactions than synthetic materials. Natural fibers like Merino wool are also better able to regulate your body temperature. When it’s hot, Merino wool keeps you cool, and when it’s cold, it insulates you. Merino wool also wicks moisture from your skin, so even when you’re sweating, it moves the sweat away from your body so you stay comfortable. A lot of people hear “wool” and think “itchy,” but well-made Merino wool is super soft and feels great against your skin.

The fewer chemicals, the better for you. The full extent of risks from toxic chemicals like PFAS and BPA aren’t yet known, but they’ve been found in tons of everyday products including clothing. BPA is a hormone-disrupting chemical that can disrupt normal body functions in many ways. Many class-action lawsuits have been filed recently in response to brands claiming their products are sustainable or healthy, but they actually contain forever chemicals.

“The crux of those lawsuits, however, is that while PFAS and other environmental toxins are present in a wide range of consumer products, Thinx misled consumers, marketing itself as an “organic, sustainable and nontoxic” alternative to traditional one-use menstrual products.” - The New York Times (linked above)

Not all Merino wool and natural fabric underwear is free of chemicals though. The manufacturing process for Merino wool can involve various treatments to enhance the performance, durability and feel of the fabric. When you’re looking for chemical-free underwear options, look for certifications like those from OEKO-TEX®. OEKO-TEX® Standard 100 certified products (all of our underwear) are tested for harmful substances — down to every thread, button and accessory on the product.

Certain natural fibers are odor-resistant. Smelling bad can put a damper on your day. Merino wool is naturally antibacterial so it prevents odor-causing bacteria from growing and keeps you from stinking, even after multiple wears. Merino wool also hand washes and dries well so you can quickly refresh Merino wool underwear when traveling or backpacking. Other natural fibers have varying levels of odor resistance, but cotton and synthetic materials like polyester are better habitats for bacteria, get smelly faster and tend to hold on to that smell longer.

One New Zealand study which involved 13 skilled olfactory (smell) assessors found that wool fabrics on average retained 66% less body odour intensity than polyester fabrics and 28% less than cotton fabrics. - Woolmark

Natural is better for the planet.

The fashion industry is one of the largest polluters in the world — choosing natural fibers is one way to reduce this impact. The other way is to buy clothing that’s well made and long lasting so you can buy less overall. Taking care of the clothes you have so they can last longer is beneficial too.

Chemicals are bad for the planet. All the chemicals used in clothing manufacturing aren’t just bad for your body, they’re bad for the planet. During production, these chemicals can contaminate the surrounding environment. The less chemicals used in production, the better.

Natural clothing = no (or fewer) microplastics. Synthetic textiles are one of the top causes of microplastics being found in our drinking water and environment. Microplastics have been linked to health issues like cancer, hormone disruption, infertility and more. Floating dust in households has been found to contain microplastic from textiles. Microplastics can also harm the people who produce these textiles. When you choose natural underwear and natural clothing, you won’t be contributing to microplastic pollution when washing them.

Natural fibers are renewable resources. Unlike synthetics that are created from petroleum and take far longer to break down, natural fibers are biodegradable, renewable and far more eco-friendly to produce. 100% Merino wool products, or Merino wool products mixed with other natural fibers like Tencel, will fully decompose when returned to the earth.

How to switch to natural Merino wool underwear

Many people start wearing natural underwear and never look back. It’s easy to make the switch – just grab a few pairs of underwear (men’s / women’s) and put them to the test in your daily life.

Natural and organic underwear can be more expensive than synthetic underwear, but all the benefits you get from natural fibers make it well worth the investment. High quality natural underwear is healthier, more sustainable and higher performing than synthetic underwear options.