At The Light Salon, meanwhile, friends Ms Laura Ferguson, a former spa director, and Ms Hannah Measures, a one-time creative producer, have erected a temple to red light and were several years ahead of the full-on boom we’re currently going through.

“Laura first came across red-light therapy back in 2006 and she was hooked (professionally and personally), the moment she discovered its benefits,” Measures says. “However, back then LED equipment was expensive, relatively unknown and available exclusively in clinics. We wanted to democratise the space, bringing light treatment to the masses.”

The result: the UK’s first LED bar in 2015. From its locations across London, The Light Salon clients can combine a session under their patented LED panel devices with peels, microneedling, microcurrents and more. Regulars include those looking to treat rosacea, melasma and eczema – or simply to prolong their youthful glow.

We know what you’re thinking: it all seems a little too good to be true, doesn’t it? How can it be that the same light rays that you’d find in, say, a thermal-imaging camera or a barcode scanner could also hold the key to your best skin ever? As it happens, the medical evidence to back it up is pretty solid (The Light Salon’s website even offers a list of clinical studies). In scientific terms, red and infrared light penetrate the body deeper than any other wavelength, stimulating the mitochondria and in turn accelerating cell regeneration and repair.

“Think of LED treatments as a rejuvenating boost to your skin cells,” says Dr Jenny Doyle, a leading cosmetic doctor at The Clinic in Holland Park. “When your skin is exposed to specific wavelengths of light, it’s like giving the cells a gentle nudge to work more efficiently.”

At The Clinic, patients looking to for long-term improvement in their skin health are placed under a medical-grade device consisting of multiple LED panels that has gone through “extensive clinical testing”. In fact, Doyle says, it’s the exact same piece of kit that’s used to treat wounds and skin conditions in the National Health Service.

And skincare is just the start, really. The latest use of red light at The Light Salon is for restimulating hair growth. “Just as LED can bring dull skin to life and give you back your glow, it can also re-invigorate lacklustre hair and restore a healthy shine,” Ferguson says. “There are four phases in the hair growth cycle. The first is anagen, the growth phase, when the hair bulb is active, and the blood supply is strong. About 90 per cent of your hair follicles are in the anagen phase and can stay that way for two to eight years. Our goal is to maintain the anagen growth phase and a healthy hair cycle by creating the best possible conditions on your scalp.

“We’re increasingly treating clients suffering from hair loss, traction alopecia and breakage resulting from stress, hormones, ageing and hair treatments. The red 633nm and near infrared 830nm wavelengths we use work by increasing the blood flow in the scalp, stimulating the hair follicles, and improving their metabolism, encouraging re-growth and minimising hair loss.”

In-clinic, treatment is typically combined with a course of microneedling to supercharge results, and before-and-after pics show noticeable improvements in thickness.

You can also size up that red-light magic and harness it for a full-body experience. In major cities, infrared-light saunas are popping up, where clients can dip in to wind down, recover post-workout or give their skin health a boost. Compared to traditional saunas, infrared versions don’t heat the air, only the body, and operate at much lower temperatures, meaning they can be used for much longer sessions for maximal benefits.

At the 11 Howard Hotel in New York, leading red-light purveyor HigherDOSE has set up an “infrared wellness spa”, use of which it says will “detox heavy metals from your body, promote healthy sleep cycles, promote a healthy glow for your skin, reduce muscle tension and help you burn calories”, all while boosting happy hormones (the Dose stands for dopamine, oxytocin, serotonin and endorphins).

In London, meanwhile, you’ll find them at the likes of cutting-edge health emporium 180 Studios, the glossy KXU gym in Chelsea and family-friendly members’ club Cloud Twelve.

Dr Jonathan Leary is the brains behind Remedy Place, the “world’s first social wellness club”, with outposts in LA and New York. For him, there was no question of not offering infrared therapy alongside the hyperbaric oxygen chambers, vitamin drips, acupuncture and ice baths. “Every treatment in the club is there because I personally use it, and because I have been using them on patients for the past eight years. It was super important for me to do my own clinical evidence to know first-hand what works.

“With that being said, having an infrared sauna in Remedy Place clubs was also crucial because of its numerous health benefits and alignment with the club’s focus on holistic wellness. These saunas can help alleviate stress, reduce muscle tension, boost the immune system and enhance skin health,” he says. “At the end of the day, try it and see how it makes you feel. The benefits will speak for themselves.”

For some, though, booking into an infrared salon or spa for a weekly fix isn’t sufficient contact time. They need those magical red beams available to them on tap. Fortunately, there’s no shortage of options here: The Light Salon offers devices of all sizes you can strap on to various body parts (including a bib for the chest and a collar for the neck). Dr Dennis Gross Skincare, too, is one of the pioneers of the at-home mask, including one specifically targeted to the eye area. (Most dermatologists I speak to recommend ensuring whichever device you pick is medically approved and clinically tested if you’re looking for noticeable results.)

Meanwhile, higher-powered panels (typically around the size of a small TV) are an increasingly popular choice for the red-light acolytes looking for maximal output, with the very best ones setting you back the price of a pair of TOM FORD shoes.

If means and space allow, you can even install your very own at-home red-light sauna in your home, as a host of A-list wellness obsessives (most notably Ms Gwyneth Paltrow) are increasingly doing. Alternatively, for a more convenient option, you can cop yourself an infrared sauna blanket, which offers much of the same benefits of a standing sauna in an easy, on-the-go format.

“Initially I wanted to set up an infrared sauna studio,” says Ms Bianca Bridges, who runs a sauna-blanket brand called Sweathouse. “As I learnt more about them, I found myself recommending them to everyone I knew.”

However, lockdowns encouraged her to pivot into blankets, which offer all skin, medical and mental health benefits, while letting users multitask. “I use mine approximately three times a week, usually while watching Netflix,” Bridges says. “It’s like a workout in itself, but it also enhances my joint and muscle recovery after the gym.”

Both the anecdotal and medical evidence is overwhelmingly positive with red-light therapy – which is to say if you were thinking of getting on board, you can be pretty confident that you’ll reap some rewards. But, before you get sucked in, know that it is also possible to overdo it.

“Generally, using the infrared sauna two to three times per week is a common recommendation for most people to experience its benefits effectively, but it’s essential to listen to your body and adjust the frequency according to how you feel,” Leary says. “Prolonged or excessive sauna sessions can lead to dehydration, heat-related illnesses or electrolyte imbalances ­– especially if you’re not adequately hydrating before, during and after the session.

Equally, for what it’s worth, no amount of red-light therapy will ever compete with the combined benefits a healthy diet, consistent sleep, regular exercise and a solid skincare routine. In terms that us menswear folk understand, think of it as a luxurious nice-to-have accessory that elevates your outfit to the next level, rather than the jeans-and-T-shirt itself.