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Light-based treatment is clearly enjoying a wave of attention. You can now buy glowing gadgets designed to address dermatological concerns and fine lines as well as aching tissues and periodontal issues, the latest being a dental hygiene device equipped with tiny red LEDs, marketed by the company as “a significant discovery in at-home oral care.” Worldwide, the sector valued at $1bn last year is expected to increase to $1.8bn within the next decade. You can even go and sit in an infrared sauna, which use infrared light to warm the body directly, the infrared radiation heats your body itself. As claimed by enthusiasts, it’s like bathing in one of those LED-lit beauty masks, boosting skin collagen, soothing sore muscles, alleviating inflammatory responses and chronic health conditions while protecting against dementia.

Research and Reservations

“It sounds a bit like witchcraft,” observes a neuroscience expert, a scientist who has studied phototherapy extensively. Of course, certain impacts of light on human physiology are proven. Sunlight enables vitamin D production, crucial for strong bones, immune defense, and tissue repair. Sunlight regulates our circadian rhythms, additionally, triggering the release of neurochemicals and hormones while we are awake, and signaling the body to slow down for nighttime. Artificial sun lamps are standard treatment for winter mood disorders to boost low mood in winter. Undoubtedly, light plays a vital role in human health.

Types of Light Therapy

While Sad lamps tend to use a mixture of light frequencies from the blue end of the spectrum, the majority of phototherapy tools use red or near-infrared wavelengths. In rigorous scientific studies, including research on infrared’s impact on neural cells, determining the precise frequency is essential. Photons represent electromagnetic waves, which runs the spectrum from the lowest-energy, longest wavelengths (radio waves) to the highest-energy (gamma waves). Light-based treatment uses wavelengths around the middle of this spectrum, including invisible ultraviolet radiation, then visible light (all the colours we see in a rainbow) and infrared light visible through night vision technology.

UV light has been used by medical dermatologists for many years to manage persistent skin disorders including eczema and psoriasis. It affects cellular immune responses, “and dampens down inflammation,” notes Dr Bernard Ho. “There’s lots of evidence for phototherapy.” UVA reaches deeper skin layers compared to UVB, whereas the LEDs we see on consumer light-therapy devices (typically emitting red, infrared or blue wavelengths) “generally affect surface layers.”

Safety Protocols and Medical Guidance

The side-effects of UVB exposure, including sunburn or skin darkening, are well known but in medical devices the light is delivered in a “narrow-band” form – signifying focused frequency bands – which minimises the risks. “Therapy is overseen by qualified practitioners, so the dosage is monitored,” says Ho. And crucially, the lightbulbs are calibrated by medical technicians, “to ensure that the wavelength that’s being delivered is fit for purpose – unlike in tanning salons, where it’s a bit unregulated, and we don’t really know what wavelengths are being used.”

Home Devices and Scientific Uncertainty

Red and blue LEDs, he says, “don’t have strong medical applications, but they may help with certain conditions.” Red light devices, some suggest, help boost blood circulation, oxygen uptake and skin cell regeneration, and activate collagen formation – a key aspiration in anti-ageing effects. “Research exists,” comments the expert. “Although it’s not strong.” In any case, with numerous products on the market, “we don’t know whether or not the lights emitted are reflective of the research that has been done. Optimal treatment times are unknown, proper positioning requirements, if benefits outweigh potential risks. Many uncertainties remain.”

Targeted Uses and Expert Opinions

One of the earliest blue-light products targeted Cutibacterium acnes, 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.” Some of his patients use it as part of their routine, he mentions, but if they’re buying a device for home use, “we advise cautious experimentation and safety verification. If it’s not medically certified, oversight remains ambiguous.”

Advanced Research and Cellular Mechanisms

At the same time, in advanced research areas, Chazot has been experimenting with brain cells, identifying a number of ways in which infrared can boost cellular health. “Pretty much everything I did with the light at that particular wavelength was positive and protective,” he says. It is partly these many and varied positive effects on cellular health that have driven skepticism about light therapy – that claims seem exaggerated. But his research has thoroughly changed his mind in that respect.

The researcher primarily focuses on pharmaceutical solutions for brain disorders, however two decades past, a GP who was developing an antiviral light treatment for cold sores sought his expertise as a biologist. “He designed tools for biological testing,” he says. “I was pretty sceptical. It was an unusual wavelength of about 1070 nanometres, which most thought had no biological effect.”

What it did have going for it, though, was that it travelled through water easily, allowing substantial bodily penetration.

Cellular Energy and Neurological Benefits

More evidence was emerging at the time that infrared light targeted the mitochondria in cells. These organelles generate cellular energy, producing fuel for biological processes. “Mitochondria exist throughout the body, even within brain tissue,” says Chazot, who prioritized neurological investigations. “Studies demonstrate enhanced cerebral circulation with light treatment, which is always very good.”

With 1070 treatment, mitochondria also produce a small amount of a molecule known as reactive oxygen species. In limited quantities these molecules, says Chazot, “activates protective proteins that safeguard mitochondria, protect cellular integrity and manage defective proteins.”

Such mechanisms indicate hope for cognitive disorders: antioxidant, anti-inflammatory, and cellular cleanup – autophagy being the process the cell uses to clear unwanted damaging proteins.

Current Research Status and Professional Opinions

Upon examining current studies on light therapy for dementia, he reports, several hundred individuals participated in various investigations, comprising his early research projects