Infrared sauna benefits: what's actually proven (and what isn't)

We sell infrared saunas, so you'd expect this page to tell you they cure everything. It won't. The infrared sauna industry has a bad habit of borrowing science from somewhere else — or inventing it — and we think you make a better buying decision (and enjoy your sauna more) knowing exactly what the evidence says.

So here's the honest version, sorted into three piles: well-supported, promising but thinner than the ads suggest, and marketing.

First, what infrared actually does

A traditional sauna heats a room to 80–100°C and the air heats you. An infrared cabin uses panels that emit infrared light — wavelengths your body absorbs directly as heat — so you sweat thoroughly at a much gentler 45–60°C air temperature. Same fundamental input in both cases: heat stress, the thing your body responds to. That matters for reading the science, as you'll see.

Well-supported

Relaxation and stress relief. The most consistent finding across sauna research of every type, and the reason most owners actually use the thing daily. Sitting in warmth with your phone in another room does what it has always done. Cleveland Clinic's review of infrared saunas lands in the same place: relaxation is the benefit with the strongest footing (Cleveland Clinic).

A real cardiovascular workout-lite response. Heat raises your heart rate and opens blood vessels much like moderate exercise does. A randomised trial published in 2021 compared infrared sauna sessions with moderate-intensity exercise and found broadly comparable acute cardiovascular responses (Complementary Therapies in Medicine, 2021). That's a session-by-session effect, not a substitute for exercise — but it's genuine physiology, not marketing.

Sleep onset. The warm-then-cool pattern after an evening session mirrors the natural body-temperature drop that helps trigger sleep. Evidence is moderate rather than overwhelming, but the mechanism is well understood and it's one of the most commonly reported real-world benefits.

Muscle recovery after exercise. Small studies in athletes suggest far-infrared sessions can reduce perceived muscle soreness after training. The studies are small, but the direction is consistent and the mechanism (increased blood flow to muscle) is plausible. It's why the home-gym crowd are the category's fastest-growing buyers.

Promising, but thinner than the ads suggest

Long-term heart health. You'll see retailers cite famous Finnish studies showing regular sauna users have markedly lower cardiovascular mortality (JAMA Internal Medicine, 2015). Two honesty flags: those cohorts used traditional Finnish saunas, not infrared — and association isn't causation. The infrared-specific evidence that does exist is interesting: Japanese "Waon therapy" — repeated far-infrared sauna sessions — has shown benefits for patients with chronic heart failure in small clinical studies, and a 2025 review covered infrared heat in peripheral arterial disease (Frontiers in Cardiovascular Medicine). Genuinely promising; not yet proven for healthy home users.

Pain relief. Small trials in conditions like fibromyalgia and rheumatoid arthritis report reduced pain from regular infrared sessions. Participants generally felt better — but the studies are small, mostly without strong control groups. If you have a pain condition, it may well help you feel better; it is not a treatment, and nobody should sell it to you as one.

Skin and circulation. Warmth increases skin blood flow, and many users report their skin looks better with regular use. Formal evidence is thin. Pleasant side effect; don't buy a sauna for it.

Marketing

"Detox." Sweat is water, salt and trace amounts of other compounds. The organs that actually remove toxins from your body are your liver and kidneys, and sweating does not meaningfully assist them — this has been examined and debunked at length (Science-Based Medicine, National Geographic). A sauna will make you sweat gloriously. It will not detox you, because you were never full of toxins that sweat could remove.

Weight loss. You'll lose weight on the scales immediately after a session — it's water, and it returns with your next glass. The calorie burn from sitting in heat is real but modest (an elevated heart rate for half an hour), nowhere near the "600–1,400 calories" figures that float around US marketing. If a retailer leads with weight loss, read everything else they say more carefully.

Cure-all claims. Anything promising to treat, reverse or cure a named disease has left the evidence entirely. Walk away — from the claim, and probably the seller.

The sensible cautions

Drink water before and after; you'll sweat more than you think at 50°C. Skip the alcohol beforehand. If you're pregnant, have a heart condition or low blood pressure, or take medication that affects blood pressure or sweating, have a word with your GP before starting regular sessions — the same advice the NHS gives for any deliberate heat exposure. And a first session of 10–15 minutes beats a heroic 45-minute debut.

The honest summary

Buy an infrared sauna for the things it demonstrably does: a genuinely relaxing daily heat session at a comfortable temperature, easier evenings into sleep, a gentle cardiovascular nudge, and faster-feeling recovery after training — all for pennies per session, from a cabin that plugs into a normal 13A socket. Don't buy one to detox, and don't buy one to lose weight — from us or anyone else.

Our Kajo range — full-spectrum, Canadian hemlock, from £1,395 with 0% finance — was built (and priced) on exactly this kind of straight talk. Questions? WhatsApp us — honest answers, no pressure.

This article is general information, not medical advice. If you have a health condition, speak to your GP before starting regular sauna use.