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Phototherapy is definitely experiencing a surge in popularity. Consumers can purchase glowing gadgets for everything from dermatological concerns and fine lines to sore muscles and periodontal issues, the newest innovation is a toothbrush equipped with tiny red LEDs, described by its makers as “a major advance in personal mouth health.” Globally, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. There are even infrared saunas available, that employ light waves rather than traditional heat sources, the infrared radiation heats your body itself. Based on supporter testimonials, it feels similar to a full-body light therapy session, stimulating skin elasticity, relaxing muscles, reducing swelling and chronic health conditions as well as supporting brain health.

Research and Reservations

“It appears somewhat mystical,” observes a neuroscience expert, a scientist who has studied phototherapy extensively. Naturally, certain impacts of light on human physiology are proven. Sunlight enables vitamin D production, crucial for strong bones, immune defense, and tissue repair. Natural light synchronizes our biological clocks, as well, stimulating neurotransmitter and hormone production during daytime, and preparing the body for rest as darkness falls. Daylight-simulating devices are a common remedy for people with seasonal affective disorder (Sad) to combat seasonal emotional slumps. So there’s no doubt we need light energy to function well.

Types of Light Therapy

Whereas seasonal affective disorder devices typically employ blue-range light, consumer light therapy products mostly feature red and infrared emissions. In rigorous scientific studies, like examinations of infrared influence on cerebral tissue, finding the right frequency is key. Light constitutes electromagnetic energy, 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, the highest energy of those being invisible ultraviolet, 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 for addressing long-term dermatological issues like vitiligo. It modulates intracellular immune mechanisms, “and dampens down inflammation,” explains a skin specialist. “There’s lots of evidence for phototherapy.” UVA goes deeper into the skin than UVB, in contrast to LEDs in commercial products (typically emitting red, infrared or blue wavelengths) “tend to be a bit more superficial.”

Risk Assessment and Professional Supervision

The side-effects of UVB exposure, such as burning or tanning, are well known but in medical devices the light is delivered in a “narrow-band” form – indicating limited wavelength spectrum – that reduces potential hazards. “Therapy is overseen by qualified practitioners, so the dosage is monitored,” says Ho. And crucially, the lightbulbs are calibrated by medical technicians, “to guarantee appropriate wavelength emission – as opposed to commercial tanning facilities, where regulations may be lax, and emission spectra aren’t confirmed.”

Consumer Devices and Evidence Gaps

Colored light diodes, he notes, “aren’t really used in the medical sense, though they might benefit some issues.” Red wavelength therapy, proponents claim, help boost blood circulation, oxygen absorption and skin cell regeneration, and activate collagen formation – a primary objective in youth preservation. “Research exists,” says Ho. “But it’s not conclusive.” Nevertheless, given the plethora of available tools, “we’re uncertain whether commercial devices replicate research conditions. Appropriate exposure periods aren’t established, proper positioning requirements, the risk-benefit ratio. Many uncertainties remain.”

Specific Applications and Professional Perspectives

One of the earliest blue-light products targeted Cutibacterium acnes, a microbe associated with acne. Scientific backing remains inadequate for regular prescription – although, explains the specialist, “it’s frequently employed in beauty centers.” Individuals include it in their skincare practices, he observes, but if they’re buying a device for home use, “we just tell them to try it carefully and to make sure it has been assessed for safety. Without proper medical classification, the regulation is a bit grey.”

Advanced Research and Cellular Mechanisms

Simultaneously, in innovative scientific domains, Chazot has been experimenting with brain cells, discovering multiple mechanisms for infrared’s cellular benefits. “Pretty much everything I did with the light at that particular wavelength was positive and protective,” he reports. It is partly these many and varied positive effects on cellular health that have driven skepticism about light therapy – that claims seem exaggerated. However, scientific investigation has altered his perspective.

The researcher primarily focuses on pharmaceutical solutions for brain disorders, but over 20 years ago, a GP who was developing an antiviral light treatment for cold sores sought his expertise as a biologist. “He developed equipment for cellular and insect experiments,” he explains. “I remained doubtful. This particular frequency was around 1070 nanometers, that many assumed was biologically inert.”

Its beneficial characteristic, however, was its efficient water penetration, enabling deeper tissue penetration.

Mitochondrial Effects and Brain Health

Additional research indicated infrared affected cellular mitochondria. Mitochondria produce ATP for cell function, generating energy for them to function. “Mitochondria exist throughout the body, particularly in neural cells,” explains the neuroscientist, who prioritized neurological investigations. “It has been shown that in humans this light therapy increases blood flow into the brain, which is generally advantageous.”

Using 1070nm wavelength, mitochondria also produce a small amount of a molecule known as reactive oxygen species. At controlled levels these compounds, explains the expert, “activates protective proteins that safeguard mitochondria, protect cellular integrity and manage defective proteins.”

All of these mechanisms appear promising for treating a brain disease: oxidative protection, swelling control, and cellular cleanup – autophagy representing cellular waste disposal.

Present Investigation Status and Expert Assessments

The last time Chazot checked the literature on using the 1070 wavelength on human dementia patients, he says, several hundred individuals participated in various investigations, comprising his early research projects