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How-ToWhat to Wear in Infrared Sauna

What to Wear in an Infrared Sauna (and What to Leave Outside)

The short answer is less. Here is why fabric choice affects session quality, what options work best, and the one thing you should never wear.

MB
Dr. Mira Brandt, PhD
Integrative Medicine
Affiliate disclosure
May 2026
Quick answer
Loose cotton shorts or a swimsuit. Or a wrapped towel. Or nothing - in private home use, minimal coverage maximizes infrared exposure. Avoid synthetics (polyester, nylon) - they trap heat uncomfortably and reduce far infrared penetration to the skin.

Why Clothing Choice Matters for Infrared

Far infrared penetrates skin directly - that is the core mechanism that distinguishes it from conventional sauna. Thick fabric between the heater and your skin reduces that contact surface. The thicker and more synthetic the fabric, the more it interferes.

Cotton absorbs sweat effectively and doesn't trap heat against the skin. Synthetics trap it. In a conventional gym context that's a minor annoyance; at 140-155°F (60-68°C) it becomes genuinely uncomfortable and reduces the efficiency of heat dissipation through sweating.

In commercial spa settings, the practical minimum is a swimsuit or shorts. In private home use, coverage is a personal choice - the tradeoff is legal requirements vs maximizing IR exposure and sweat efficiency.

Your Options, Ranked

1
Nothing or minimal
Best IR exposure, maximum sweat absorption by towel beneath you. Private home use only. Provides the highest thermal efficiency of any option.
2
Cotton bikini or swimsuit
Good balance of coverage and performance. Absorbent, comfortable, works in any setting - commercial or home. Most popular choice. Cotton preferred over polyester blend.
3
Loose cotton shorts and sports bra or no top
Practical and comfortable for longer sessions. Good airflow, easy to adjust. Recommended for 35-45 min sessions where comfort matters more than minimal coverage.
4
Towel wrap
Traditional approach. Effective, keeps the bench dry, easy to adjust as needed. Works in any setting. Slightly more cumbersome than a swimsuit but preferred by many regular users.
5
Loose cotton t-shirt and shorts
Fine but unnecessary coverage reduces some IR exposure. If you prefer this for comfort, use lightweight 100% cotton. Avoid heavy gym-weight cotton.

What to Never Wear

Synthetics
Polyester, nylon, and spandex trap heat against skin, feel suffocating at 140°F (60°C)+, reduce IR penetration, and retain sweat odor. No performance benefit in this context.
Metal jewelry
Conducts heat and can cause localized burns on prolonged skin contact at session temperatures. Remove rings, necklaces, and bracelets before entering.
Heavy cotton
Counterproductive bulk. Pockets collect sweat. Heavy gym-weight hoodies or sweatpants add unnecessary weight and restrict airflow.
Street clothes
Bring in debris and contaminants that degrade the wood over time. Buttons and metal zips can get uncomfortably hot against skin.

Hair Care in an Infrared Sauna

Keratin bonds begin degrading above approximately 60°C (140°F). Regular sauna sessions at full temperature can dry and weaken hair over time - particularly if hair is already chemically treated or color-processed.

Best options for hair
  • +Loose updo or bun: Not tight - scalp circulation matters. A loose bun reduces direct heat exposure to ends and length without restricting blood flow.
  • +Loose towel over hair: Simple and effective. Creates a barrier that reduces peak heat at the scalp.
  • +Wet hair: Protects slightly through evaporative cooling on the scalp, but adds humidity inside the cabin. A minor consideration in home units.
  • +Product residue warning: If you have conditioner, dry shampoo, or styling product in your hair, it will melt and potentially transfer to the sauna wood. Rinse or use a towel barrier.

Eye Protection

Standard far infrared wavelengths (5.6-1000 microns) are very poorly absorbed by the aqueous humor and lens tissue. Eye risk from a standard far-IR sauna at normal bench distances is minimal - there is no clinical evidence of eye damage from conventional far infrared sauna exposure.

Full-spectrum saunas that include near infrared panels (0.76-1.4 microns) present a slightly different picture. Near IR is more readily absorbed by eye tissue, particularly at close range with direct exposure. If your sauna has near-IR panels positioned at eye level and you use it at close range, wrap-around glasses designed for near-IR exposure are a sensible and inexpensive precaution.

Practical answer
For standard far IR saunas: no eye protection needed. For full-spectrum units with near-IR panels at close range: near-IR wrap glasses are available for under $30 and eliminate the variable entirely.

Phones and Electronics

Most smartphones are rated to 45°C (113°F) maximum operating temperature. Infrared sauna cabins run 49-68°C (120-155°F). Short 15-minute sessions at lower temperature settings carry low risk. Sessions at 155°F (68°C) for 35-45 minutes place phones well outside their thermal rating.

Risks include: permanent battery capacity loss, thermal shutdown during the session, and in rare cases lithium battery failure from sustained overheating. A Bluetooth speaker outside the cabin paired with your phone on a nearby surface is the practical solution for those who want music or podcasts during sessions.

FAQ

Can I wear clothes in an infrared sauna?+
Yes. Cotton is ideal. Loose cotton shorts, a swimsuit, or a towel wrap all work well. The main thing to avoid is synthetic fabric - polyester and nylon trap heat and reduce far infrared contact with your skin.
Should you wear a swimsuit in infrared sauna?+
A swimsuit is one of the best options - absorbent, comfortable, appropriate for any setting (commercial or home), and allows sufficient IR contact. Cotton is preferable to polyester.
Is it better to be naked in infrared sauna?+
In terms of infrared exposure and sweating efficiency: yes, minimal coverage maximizes both. In practice, a lightweight cotton suit or towel is nearly as effective and more comfortable for most people.
What material is best to wear in infrared sauna?+
100% cotton. It absorbs sweat, doesn't trap heat uncomfortably, and doesn't interfere with far infrared penetration the way synthetic fabrics do.
Do you need eye protection in an infrared sauna?+
For standard far infrared cabins: no, the wavelengths are not well absorbed by eye tissue at normal distances. For full-spectrum saunas with near-IR panels at close range: protective wrap glasses are a low-cost sensible option.
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Written by
Aleksi Suoninen
Helsinki, Finland. Grew up with sauna as a daily ritual - Finland has more saunas than cars. Tests and writes about infrared sauna products from a Nordic perspective where heat therapy needs no justification.
FinlandIndependent tester

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