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Phototherapy is certainly having a surge in popularity. Consumers can purchase illuminated devices targeting issues like dermatological concerns and fine lines as well as sore muscles and periodontal issues, recently introduced is a toothbrush enhanced with tiny red LEDs, marketed by the company as “a major advance in personal mouth health.” 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, where instead of hot coals (real or electric) heating the air, 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, easing muscle tension, relieving inflammation and chronic health conditions and potentially guarding against cognitive decline.

Understanding the Evidence

“It sounds a bit like witchcraft,” notes a Durham University professor, who has researched light therapy for two decades. Of course, some of light’s effects on our bodies are well established. Sunlight helps us make vitamin D, needed for bone health, immunity, muscles and more. Sunlight regulates our circadian rhythms, as well, triggering the release of neurochemicals and hormones while we are awake, and winding down bodily functions for sleep as it fades into night. Sunlight-imitating lamps are standard treatment for winter mood disorders 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, most other light therapy devices deploy red or infrared light. In serious clinical research, including research on infrared’s impact on neural cells, finding the right frequency is key. Photons represent electromagnetic waves, spanning from low-energy radio waves to the highest-energy (gamma waves). Light-based treatment uses wavelengths around the middle of this spectrum, including invisible ultraviolet radiation, then the visible spectrum we perceive as colors and finally infrared detectable with special equipment.

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 reduces inflammatory processes,” explains a skin specialist. “Substantial research supports light therapy.” UVA reaches deeper skin layers compared to UVB, in contrast to LEDs in commercial products (usually producing colored light emissions) “tend to be a bit more superficial.”

Safety Considerations and Medical Oversight

The side-effects of UVB exposure, such as burning or tanning, are understood but clinical devices employ restricted wavelength ranges – indicating limited wavelength spectrum – that reduces potential hazards. “It’s supervised by a healthcare professional, thus exposure is controlled,” explains the dermatologist. And crucially, the lightbulbs are calibrated by medical technicians, “to guarantee appropriate wavelength emission – different from beauty salons, where oversight might be limited, and we don’t really know what wavelengths are being used.”

Commercial Products and Research Limitations

Colored light diodes, he notes, “aren’t really used in the medical sense, but they may help with certain conditions.” Red LEDs, it is proposed, improve circulatory function, oxygen utilization and skin cell regeneration, and promote collagen synthesis – a key aspiration in anti-ageing effects. “Studies are available,” states the dermatologist. “But it’s not conclusive.” Regardless, given the plethora of available tools, “it’s unclear if device outputs match study parameters. We don’t know the duration, how close the lights should be to the skin, if benefits outweigh potential risks. There are lots of questions.”

Specific Applications and Professional Perspectives

Early blue-light applications focused on skin microbes, bacteria linked to pimples. The evidence for its efficacy isn’t strong enough for it to be routinely prescribed by doctors – even though, explains the specialist, “it’s commonly used in cosmetic clinics.” Individuals include it in their skincare practices, he mentions, though when purchasing home devices, “we advise cautious experimentation and safety verification. Unless it’s a medical device, standards are somewhat unclear.”

Advanced Research and Cellular Mechanisms

Meanwhile, in innovative scientific domains, Chazot has been experimenting with brain cells, discovering multiple mechanisms for infrared’s cellular benefits. “Virtually all experiments with specific wavelengths showed beneficial and safeguarding effects,” he states. 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.

Chazot mostly works on developing drug treatments for neurodegenerative diseases, however two decades past, a physician creating light-based cold sore therapy requested his biological knowledge. “He developed equipment for cellular and insect experiments,” he says. “I was quite suspicious. This particular frequency was around 1070 nanometers, that many assumed was biologically inert.”

The advantage it possessed, however, was that it travelled through water easily, allowing substantial bodily penetration.

Mitochondrial Effects and Brain Health

Growing data suggested infrared influenced energy-producing organelles. These organelles generate cellular energy, producing fuel for biological processes. “Every cell in your body has mitochondria, even within brain tissue,” says Chazot, who prioritized neurological investigations. “It has been shown that in humans this light therapy increases blood flow into the brain, which is always very good.”

With specific frequency application, cellular power plants create limited oxidative molecules. At controlled levels these compounds, 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: free radical neutralization, swelling control, and waste removal – autophagy representing cellular waste disposal.

Present Investigation Status and Expert Assessments

Upon examining current studies on light therapy for dementia, he states, about 400 people were taking part in four studies, comprising his early research projects