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Phototherapy is certainly having a moment. Consumers can purchase light-emitting tools targeting issues like complexion problems and aging signs to muscle pain and oral inflammation, the latest being an oral care tool enhanced with miniature red light sources, marketed by the company as “a breakthrough for domestic dental hygiene.” Worldwide, the industry reached $1 billion in 2024 and is forecast to expand to $1.8 billion by 2035. You can even go and sit in an infrared sauna, which use infrared light to warm the body directly, your body is warmed directly by infrared light. As claimed by enthusiasts, it’s like bathing in one of those LED-lit beauty masks, boosting skin collagen, soothing sore muscles, reducing swelling and persistent medical issues and potentially guarding against cognitive decline.

Understanding the Evidence

“It appears somewhat mystical,” observes a Durham University professor, professor in neuroscience at Durham University and a convert to the value of light therapy. Certainly, certain impacts of light on human physiology are proven. Sunlight enables vitamin D production, needed for bone health, immunity, muscles and more. Natural light synchronizes our biological clocks, as well, triggering the release of neurochemicals and hormones while we are awake, and signaling the body to slow down for nighttime. Daylight-simulating devices are standard treatment for winter mood disorders to combat seasonal emotional slumps. Undoubtedly, light plays a vital role in human health.

Various Phototherapy Approaches

Although mood lamps generally utilize blue-spectrum frequencies, consumer light therapy products mostly feature red and infrared emissions. In serious clinical research, including research on infrared’s impact on neural cells, identifying the optimal wavelength is crucial. Light constitutes electromagnetic energy, which runs the spectrum from the lowest-energy, longest wavelengths (radio waves) to high-energy gamma radiation. Light-based treatment employs mid-spectrum wavelengths, with ultraviolet representing the higher energy invisible light, then the visible spectrum we perceive as colors and finally infrared detectable with special equipment.

UV light has been used by medical dermatologists for many years for addressing long-term dermatological issues like vitiligo. It affects cellular immune responses, “and suppresses swelling,” notes Dr Bernard Ho. “There’s lots of evidence for phototherapy.” UVA reaches deeper skin layers compared to UVB, in contrast to LEDs in commercial products (which generally deliver red, infrared or blue light) “generally affect surface layers.”

Risk Assessment and Professional Supervision

UVB radiation effects, including sunburn or skin darkening, are recognized but medical equipment uses controlled narrow-band delivery – indicating limited wavelength spectrum – that reduces potential hazards. “It’s supervised by a healthcare professional, thus exposure is controlled,” explains the dermatologist. Essentially, the lightbulbs are calibrated by medical technicians, “to guarantee appropriate wavelength emission – as opposed to commercial tanning facilities, where oversight might be limited, and we don’t really know what wavelengths are being used.”

Commercial Products and Research Limitations

Red and blue LEDs, 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 skin cell regeneration, and stimulate collagen production – an important goal for anti-aging. “Research exists,” states the dermatologist. “Although it’s not strong.” Nevertheless, given the plethora of available tools, “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, the risk-benefit ratio. Many uncertainties remain.”

Specific Applications and Professional Perspectives

Early blue-light applications focused on skin microbes, bacteria linked to pimples. Scientific backing remains inadequate for regular prescription – although, says Ho, “it’s often seen in medical spas or aesthetics practices.” Some of his patients use it as part of their routine, he observes, however for consumer products, “we just tell them to try it carefully and to make sure it has been assessed for safety. Unless it’s a medical device, the regulation is a bit grey.”

Advanced Research and Cellular Mechanisms

Simultaneously, in advanced research areas, 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 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.

Chazot mostly works on developing drug treatments for neurodegenerative diseases, however two decades past, a doctor developing photonic antiviral treatment consulted his scientific background. “He developed equipment for cellular and insect experiments,” he says. “I remained doubtful. This particular frequency was around 1070 nanometers, that many assumed was biologically inert.”

What it did have going for it, however, was its ability to transmit through aqueous environments, allowing substantial bodily penetration.

Mitochondrial Effects and Brain Health

More evidence was emerging at the time that infrared light targeted the mitochondria in cells. Mitochondria produce ATP for cell function, generating energy for them to function. “Every cell in your body has mitochondria, even within brain tissue,” notes the researcher, who prioritized neurological investigations. “Research confirms improved brain blood flow with phototherapy, which is consistently beneficial.”

Using 1070nm wavelength, energy organelles generate minimal reactive oxygen compounds. In limited quantities these molecules, explains the expert, “stimulates so-called chaperone proteins which look after your mitochondria, preserve cell function and eliminate damaged proteins.”

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

Current Research Status and Professional Opinions

The last time Chazot checked the literature on using the 1070 wavelength on human dementia patients, he reports, approximately 400 participants enrolled in multiple trials, including his own initial clinical trials in the US