What do I wear in the Sauna?
The short answer: Wear as little as possible and wear all natural fibers. Linen and merino wool are the two materials that regulate moisture and body temperature through natural fiber structure.
When you think about it, not too long ago, these fibers protected the very living organisms that grew them. Cellulose for the flax plant and keratin-based protein from the merino sheep. These textiles have been used by ancient human civilizations for millennia for their naturally 'high performance' properties.
The Best Suit is Your Birthday Suit
Traditionally, the best sauna "outfit" was none other than your birthday suit. In many European countries it is standard to wear nothing but a towel, removing it to sit on once you enter. This remains common practice in Finland, Germany, and much of Scandinavia.
As sauna research on athletic recovery and cardiovascular health has accumulated, co-ed facilities have grown and the default to nudity has shifted. Most facilities are not okay with nudity and due to personal reasons, many sauna-goers aren't fully comfortable with nudity either, which is 100% okay. We aim to bridge the gap so that sauna enthusiasts can enjoy the healing benefits of heat therapy while wearing natural fiber clothing designed for how the body sweats and detoxes.
Add in the rise in popularity of contrast therapy, alternating between hot and cold exposures, and it is not practical to sauna in the nude to then rinse off and fully submerge oneself in a cold plunge. (It is one thing for us ladies but can you imagine the discomfort of many men cold plunging in a co-ed facility in the nude?) All that being said, we stand by the opinion that there is currently a lack of natural fiber options on the market and we stand to offer a range of apparel so that everyone can sauna with maximum comfort and enjoyment.
So the question becomes: what do you wear?
Why Most Athletic Wear is Problematic In High Temperatures
Most athletic wear is made from petrochemical-derived synthetic fibers: polyester, nylon, spandex. These materials gained market dominance through cheap mass production, elasticity, and hydrophobic properties. Polyester hardly gets wet, it only absorbs 0.4%–1% of its weight, which made it the preferred swimwear material because at the fiber level, it is essentially plastic.
In a sauna environment, that becomes a problem. Synthetics trap heat against the body rather than allowing thermal regulation. At elevated temperatures, some synthetics off-gas volatile organic compounds from polymer chains, a concern in enclosed high-heat spaces.
What Natural Fibers Do Differently
Historically, sauna masters wore clothing made from natural fibers, primarily linen and wool.
LINEN is composed of hollow cellulose fibers. This structure allows linen to pull moisture away from skin through capillary action, releasing it as vapor rather than holding it against the body. Linen dries faster than cotton and becomes progressively softer with repeated washing and heat exposure. Its tensile strength, among the highest of any natural fiber, means it holds structure across repeated sauna and cold plunge cycles.
COTTON is highly absorbent, which makes it excellent for towels, but that same property is a liability in the sauna. Cotton saturates, grows heavy, and dries slowly, making it not necessarily the first choice for repeated contrast therapy use.
Knitted vs. Woven Linen: Why It Matters
Not all linen performs the same. Woven linen has no stretch and requires a significant break-in period before it softens against skin. Knitted linen, constructed through interlocking loops rather than a crossed weave, provides four-way stretch and is soft from first wear.
For sauna and cold plunge environments where you need freedom of movement and immediate comfort against bare skin, knitted linen comes out as the more functional choice, akin to the knitted synthetic fabrics commonly used for swim apparel.
RITUAL TEXTILES builds its LINEN / SAUNA line exclusively from Turkish knitted linen for this reason.
The Recommendation
For regular sauna use, wear as little as possible, made entirely from natural fibers. Minimal coverage reduces the barrier between skin and the sauna's thermal environment.
Key Takeaways
- Synthetic athletic wear traps heat and does not regulate moisture through fiber structure
- Linen outperforms cotton in the sauna due to hollow fiber structure and faster dry time
- Minimal, natural-fiber coverage is the functional standard for contrast therapy
FAQ
Can you wear a sports bra and leggings in a sauna? You can, but most are made from polyester or nylon, synthetic fibers that trap heat and redirect moisture rather than regulating it. In a high-heat environment, natural fibers perform better.
What is the best fabric for sauna wear? Linen and merino wool are the two strongest natural fiber options. Linen wicks moisture through hollow fiber capillary action and dries quickly. Merino regulates body temperature across a wider range and holds up well through both sauna and cold plunge transitions.
Is cotton okay to wear in a sauna? Cotton is natural but highly absorbent. It saturates under sauna conditions and dries slowly, making it less practical than linen for contrast therapy.
Can you wear linen in a cold plunge? Yes. Knitted linen maintains structure in cold water and dries faster than cotton.