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Light-based treatment is certainly having a surge in popularity. You can now buy glowing gadgets targeting issues like complexion problems and aging signs to aching tissues and gum disease, the latest being a toothbrush equipped with small red light diodes, marketed by the company as “a breakthrough in at-home oral care.” Internationally, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. You can even go and sit in an infrared sauna, that employ light waves rather than traditional heat sources, your body is warmed directly by infrared light. As claimed by enthusiasts, it feels similar to a full-body light therapy session, stimulating skin elasticity, soothing sore muscles, reducing swelling and chronic health conditions and potentially guarding against cognitive decline.

Understanding the Evidence

“It appears somewhat mystical,” says Paul Chazot, who has researched light therapy for two decades. Of course, we know light influences biological functions. Sunlight enables vitamin D production, essential for skeletal strength, immune function, and muscular health. Sunlight regulates our circadian rhythms, additionally, triggering the release of neurochemicals and hormones while we are awake, and preparing the body for rest as darkness falls. Daylight-simulating devices are a common remedy for people with seasonal affective disorder (Sad) to elevate spirits during colder months. So there’s no doubt we need light energy to function well.

Different Light Modalities

Although mood lamps generally utilize blue-spectrum frequencies, most other light therapy devices deploy red or infrared light. During advanced medical investigations, like examinations of infrared influence on cerebral tissue, finding the right frequency is key. Light is a form of electromagnetic radiation, extending from long-wavelength radiation to the highest-energy (gamma waves). Light-based treatment uses wavelengths around the middle of this spectrum, with ultraviolet representing the higher energy invisible light, then the visible spectrum we perceive as colors and then infrared (which we can see with night-vision goggles).

Ultraviolet treatment has been employed by skin specialists for decades to manage persistent skin disorders including eczema and psoriasis. It affects cellular immune responses, “and suppresses swelling,” explains a dermatology expert. “Substantial research supports light therapy.” UVA penetrates skin more deeply than UVB, whereas the LEDs we see on consumer light-therapy devices (typically emitting red, infrared or blue wavelengths) “typically have shallower penetration.”

Risk Assessment and Professional Supervision

The side-effects of UVB exposure, including sunburn or skin darkening, are recognized but medical equipment uses controlled narrow-band delivery – meaning smaller wavelengths – that reduces potential hazards. “Treatment is monitored by medical staff, thus exposure is controlled,” explains the dermatologist. Essentially, the light sources are adjusted by technical experts, “to ensure that the wavelength that’s being delivered is fit for purpose – unlike in tanning salons, where it’s a bit unregulated, and emission spectra aren’t confirmed.”

Commercial Products and Research Limitations

Colored light diodes, he notes, “aren’t typically employed clinically, but they may help with certain conditions.” Red wavelength therapy, proponents claim, help boost blood circulation, oxygen uptake and dermal rejuvenation, and stimulate collagen production – a key aspiration in anti-ageing effects. “Studies are available,” comments the expert. “However, it’s limited.” In any case, amid the sea of devices now available, “it’s unclear if device outputs match study parameters. Appropriate exposure periods aren’t established, proper positioning requirements, the risk-benefit ratio. Numerous concerns persist.”

Treatment Areas and Specialist Views

Early blue-light applications focused on skin microbes, a microbe associated with acne. The evidence for its efficacy isn’t strong enough for it to be routinely prescribed by doctors – although, notes the dermatologist, “it’s frequently employed in beauty centers.” Individuals include it in their skincare practices, he says, however for consumer products, “we recommend careful testing and security confirmation. If it’s not medically certified, oversight remains ambiguous.”

Cutting-Edge Studies and Biological Processes

At the same time, in a far-flung field of pioneering medical science, Chazot has been experimenting with brain cells, revealing various pathways for light-enhanced cell function. “Nearly every test with precise light frequencies demonstrated advantageous outcomes,” he reports. It is partly these many and varied positive effects on cellular health that have driven skepticism about light therapy – that it’s too good to be true. Yet, experimental evidence has transformed his viewpoint.

The scientist mainly develops medications for neurological conditions, though twenty years earlier, a GP who was developing an antiviral light treatment for cold sores sought his expertise as a biologist. “He created some devices so that we could work with them with cells and with fruit flies,” he explains. “I was pretty sceptical. It was an unusual wavelength of about 1070 nanometres, that many assumed was biologically inert.”

Its beneficial characteristic, though, was its ability to transmit through aqueous environments, allowing substantial bodily penetration.

Mitochondrial Effects and Brain Health

Additional research indicated infrared affected cellular mitochondria. Mitochondria produce ATP for cell function, producing fuel for biological processes. “Mitochondria exist throughout the body, particularly in neural cells,” notes the researcher, who concentrated on cerebral applications. “It has been shown that in humans this light therapy increases blood flow into the brain, which is generally advantageous.”

With specific frequency application, cellular power plants create limited oxidative molecules. In low doses this substance, explains the expert, “stimulates so-called chaperone proteins which look after your mitochondria, preserve cell function and eliminate damaged proteins.”

All of these mechanisms appear promising for treating a brain disease: antioxidant, anti-inflammatory, and cellular cleanup – autophagy representing cellular waste disposal.

Current Research Status and Professional Opinions

The last time Chazot checked the literature on using the 1070 wavelength on human dementia patients, he says, approximately 400 participants enrolled in multiple trials, comprising his early research projects