Saunas have been having a moment and it’s not just because the temperature has dropped. Though popular in Europe, they've never quite caught on in the same way here in Blighty. Typically seen as an add-on at the gym or a little mindful wellness extra, we’re now seeing sauna culture come into its own.

Driven by the rise in cold water swimming, the wellness boom and a desire for healthier socialising options, the British Sauna Society reported that the number of public saunas in the UK doubled between 2023 and 2024, and they expect 2025 end of year figures to show that they have doubled again.

It’s not just traditional Nordic cabins—futuristic infrared pods have become all the rage as users extol the many benefits of heat therapy, and claims that range from detoxification and lymphatic flow to collagen stimulation and barrier strengthening. But while the post-sauna glow is undeniable, the science behind it is far more nuanced than social media suggests.

We asked EV Expert, Aesthetician and Ace Skin Health Clinic Founder, Corina Mihalache to talk us through what heat really does to the skin, the difference between sauna types and who should be approaching this trend with caution.

Heat exposure explained

According to Mihalache, the body responds to heat in a very specific way. “When skin is exposed to high heat, a fascinating cascade of physiological responses is triggered," she explains. "The body's immediate priority is thermoregulation; blood vessels dilate to bring more blood to the skin's surface for cooling. This increased circulation delivers oxygen and nutrients to skin cells while removing metabolic waste products.”

This is what triggers that coveted sauna glow: as your oxygen-rich blood rises to the surface, a temporary brightness descends upon your complexion. Next, “the heat activates heat shock proteins, which serve as cellular protectors, helping to repair damaged proteins and support overall skin resilience,” adds Mihalache.

Sweat glands begin to work harder too, and as sweat and sebum warm and liquefy, surface debris like dead skin, sebum, dirt and dust lift more easily post cleansing. This is one of the reasons that skin looks smoother and fresher immediately after a sauna.

Traditional sauna vs infrared

Both forms of sauna create heat stress, but in different ways. Traditional Nordic saunas heat the air, and reach anywhere between 65-110 degrees. The heat surrounds the body, creating intense sweating and a strong cardiovascular response. Infrared saunas work at lower temperatures, typically 49-60 degrees as they use light to heat the body directly rather than the air. The infrared light penetrates the skin and tissues, and because the human body is about 70 per cent water, it efficiently absorbs this energy and directly raises your core body temperature.

“For the skin specifically, traditional saunas create more surface-level heat stress and intense sweating, while infrared saunas provide gentler, more penetrating warmth. This makes infrared rooms easier to tolerate, particularly for sensitive skin, because the sweat response builds more gradually,” Mihalache explains. Does this make one inherently better? “The end result is similar, but the method and comfort level differ,” she adds.

She points out that infrared heat penetrates deeper, which is where some of the more ambitious claims originate. “Infrared saunas may have an edge when it comes to deeper tissue penetration, potentially stimulating fibroblast activity and collagen production more effectively,” says Mihalache. Some studies even point to improvements in wound healing and reduced inflammation at a cellular level, which could have a positive influence on how our skin looks and behaves.

The science

While there are studies to back up some benefit claims, there are others that need tempering. Improved circulation is one of the strongest, as vasodilation (the widening of blood vessels) is measurable and delivers nutrients to the skin far more efficiently. However, lymphatic flow improves only indirectly, as it’s movement—not heat—that drives the lymphatic system, although relaxation of the surrounding muscles may help.

Detoxification is where things slip into myth territory. “Although we excrete some toxins through sweat, the liver and kidneys carry out most detoxification,” stresses Mihalache.

As for collagen stimulation, heat shock proteins do play a role in cellular repair, but the results are modest, meaning anyone hoping for a sauna-induced lifting effect will be disappointed. Mihalache is clear: “Saunas aren’t collagen boosting, anti-ageing treatments and they certainly don’t replace facial treatments.”

The downside 

Increased heat has a downside as far as the skin is concerned. “It temporarily compromises the skin barrier by increasing transepidermal water loss, depleting moisture and weakening lipids. If you don’t hydrate properly afterwards, you’ll likely notice a tight, raw, sensitised feeling,” explains Mihalache. In other words, the glow is genuine and can be lasting, but only if you replenish the water lost internally by way of downing some extra glasses of the water and electrolytes, as well as externally with humectant and ceramide-rich moisturisers.

Vasodilation can also be an issue for anyone with rosacea, melasma, eczema, dermatitis or highly reactive skin as saunas can trigger flushing, itchiness, inflammation or pigment activity,” warns Mihalache. Inflammatory acne is also a concern, as heat can intensify inflammation and increase sebum production.

It's also worth noting that for melanin-rich skin, “an extra layer of caution is necessary. Excessive or prolonged heat can trigger inflammation or post-inflammatory pigmentation, so it is important to keep sessions shorter and cooler, and to ensure consistent use of SPF and barrier repair afterwards,” adds Mihalache.

Are saunas skin saviours?

While saunas are having a moment and the benefits are real, they’re just not miraculous. When used mindfully and paired with proper hydration and barrier repair, saunas can support circulation, enhance radiance and complement a broader health routine. But when it comes to the skin, evidence suggests that they’re not a necessity and can do more harm than good.

As Mihalache reminds us, “more is not always better. Sauna sessions should support your skin, not stress it.” Make it part of your wellness routine if you have no contraindications, but spend no more than 10 minutes getting your sweat on. And don’t forget to always cleanse or rinse your face and body immediately after your session, to avoid the negative impact dry sweat can have on the skin.