FAQs

Product & Performance

What is THRML°?

THRML° is a performance-focused thermoregulation brand. Our products are designed to strategically manage heat exposure—protecting where heat concentrates and cooling where thermal strain accumulates.

Why wear a sauna cap?

Heat rises and accumulates at the highest point of the body—the head. Without regulation, this accelerates fatigue and shortens sessions. The THRML° Sauna Cap provides thermal insulation to slow heat overload, supporting longer, more controlled exposure.

Why cooling briefs for sauna use?

The body’s most temperature-sensitive regions can experience elevated thermal strain during prolonged heat exposure. THRML° Cooling Briefs integrate targeted cooling inserts to support balanced thermoregulation and improved heat tolerance.

Do your products increase sauna temperature?

No. THRML° products do not increase environmental heat. They are designed to help regulate the body’s response to heat exposure.

Are there medical benefits?

THRML° products are not medical devices. While sauna use has been associated with various wellness outcomes, our products are designed to support thermoregulation and performance—not to diagnose, treat, cure, or prevent disease.

Always consult a healthcare professional before engaging in sauna use if you have medical conditions.

Use & Care

How long can I stay in the sauna while wearing THRML° products?

Duration varies based on individual tolerance. Always listen to your body, remain hydrated, and exit the sauna if you feel dizzy, overheated, or unwell.

THRML° products are designed to support prolonged exposure—but they do not eliminate the risks of heat stress.

How do I use the cooling inserts?

Freeze the inserts prior to use. Insert them into the designated pocket before entering the sauna. Remove and refreeze after use.

Do not use damaged inserts.

How should I wash my products?

Sauna Cap:

- Hand wash recommended

- Lay flat or hang dry

- Do not bleach or tumble dry

Cooling Brief:

- Machine wash cold

- Air dry recommended

- Do not bleach

- Do not use fabric softeners

Cooling Inserts:

- Wipe clean only

- Do not puncture or machine wash

Orders & Shipping

When will my order ship?

Orders are processed within 1–3 business days unless otherwise stated. You will receive tracking information once shipped.

Do you ship internationally?

If international shipping is available, duties and customs fees are the responsibility of the customer.

What if my package says delivered but I didn’t receive it?

Once marked delivered by the carrier, THRML° is not responsible for lost or stolen packages. Please contact the carrier directly.

Returns & Refunds

What is your return policy?

Returns must be requested within 30 days of delivery. Items must be unused, unworn, and in original packaging.

Due to hygiene standards, worn underwear cannot be returned.

Cooling inserts must be unused.

What if my item is defective?

Contact us within 7 days of delivery with photos and your order number. We will review and determine appropriate resolution.

Safety

Is sauna use safe for everyone?

Sauna use involves inherent risks including dehydration, overheating, and cardiovascular stress. Individuals with heart conditions, respiratory issues, or heat sensitivity should consult a healthcare professional prior to use.

THRML° products do not eliminate the risks of heat exposure.

Behind the Sauna Cap

Intentional high-heat exposure creates a measurable physiological response: skin temperature rises, sweating increases, cardiovascular demand elevates, and the body works continuously to regulate heat stress. But the intensity of that experience is not driven by core temperature alone — local thermal sensation matters, and the head is one of the most influential regions in how heat is perceived overall. Research on thermoregulation and regional comfort has shown that warming or cooling the head can disproportionately affect whole-body heat perception, which is what makes a sauna cap scientifically meaningful. Rather than interrupting the sauna experience, a merino wool sauna cap is designed to create a buffered microclimate around the scalp and hair, helping reduce the abruptness of direct dry heat exposure in one of the body’s most thermally sensitive areas. Merino wool is particularly relevant because it combines breathable insulation with excellent moisture-vapor buffering, meaning it can help regulate the environment around the head without trapping heat in the way less functional materials might. While clinical trials specifically on sauna caps remain limited, the physiology behind the category is well supported: by managing local heat transfer, humidity, and exposure at the scalp, a sauna cap is designed to support comfort, help shield hair and skin from intense direct heat, and preserve the integrity of the sauna session through more controlled thermal protection.

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Behind the Cooling Briefs

Male reproductive physiology depends heavily on temperature regulation, which is why the testes are positioned outside the body in the first place: normal spermatogenesis functions best below core body temperature, and even modest increases in scrotal heat can negatively influence sperm production, motility, and related reproductive markers. That relationship between temperature and male reproductive health is one of the most established findings in the literature, and it is further supported by studies showing that factors like prolonged sitting, tight clothing, and external heat exposure can all contribute to increased local thermal burden. Cooling briefs are built around that biological reality. Rather than making exaggerated claims, the strongest scientific case is that they serve as a targeted temperature-management system for a region where heat regulation matters. Human feasibility research has even shown that specialized cooling underwear can meaningfully reduce scrotal skin temperature in real-world conditions, reinforcing the idea that wearable cooling can alter the local thermal environment without disrupting daily function. So while no responsible product should claim to act as a fertility treatment on its own, the mechanism is clear and well grounded: by helping reduce localized heat accumulation in one of the body’s most temperature-sensitive regions, cooling briefs are designed to support a cooler, more controlled environment where thermoregulation, comfort, and reproductive biology intersect.