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Phototherapy is certainly having a surge in popularity. You can now buy glowing gadgets designed to address skin conditions and wrinkles along with aching tissues and gum disease, the latest being a dental hygiene device equipped with small red light diodes, marketed by the company as “a breakthrough in personal mouth health.” Internationally, the industry reached $1 billion in 2024 and is forecast to expand to $1.8 billion by 2035. Options include full-body infrared sauna sessions, where instead of hot coals (real or electric) heating the air, the infrared radiation heats your body itself. According to its devotees, the experience resembles using an LED facial mask, enhancing collagen production, soothing sore muscles, relieving inflammation and long-term ailments as well as supporting brain health.

The Science and Skepticism

“It appears somewhat mystical,” observes a neuroscience expert, who has researched light therapy for two decades. Naturally, certain impacts of light on human physiology are proven. Sunlight helps us make vitamin D, crucial for strong bones, immune defense, and tissue repair. Natural light synchronizes our biological clocks, too, stimulating neurotransmitter and hormone production during daytime, and winding down bodily functions for sleep as it fades into night. Artificial sun lamps are standard treatment for winter mood disorders to boost low mood in winter. So there’s no doubt we need light energy to function well.

Different Light Modalities

Whereas seasonal affective disorder devices typically employ blue-range light, consumer light therapy products mostly feature red and infrared emissions. In rigorous scientific studies, such as Chazot’s investigations into the effects of infrared on brain cells, finding the right frequency is key. Light constitutes electromagnetic energy, extending from long-wavelength radiation to short-wavelength gamma rays. Therapeutic light application utilizes intermediate light frequencies, with ultraviolet representing the higher energy invisible light, followed by visible light encompassing rainbow colors and then infrared (which we can see with night-vision goggles).

UV light has been used by medical dermatologists for many years for addressing long-term dermatological issues like vitiligo. It works on the immune system within cells, “and suppresses swelling,” notes a dermatology expert. “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 (usually producing colored light emissions) “tend to be a bit more superficial.”

Risk Assessment and Professional Supervision

Potential UVB consequences, including sunburn or skin darkening, are understood but clinical devices employ restricted wavelength ranges – indicating limited wavelength spectrum – which decreases danger. “Therapy is overseen by qualified practitioners, meaning intensity is regulated,” notes the specialist. And crucially, the devices are tuned by qualified personnel, “to ensure that the wavelength that’s being delivered is fit for purpose – as opposed to commercial tanning facilities, where regulations may be lax, and we don’t really know what wavelengths are being used.”

Consumer Devices and Evidence Gaps

Red and blue LEDs, he explains, “aren’t typically employed clinically, though they might benefit some issues.” Red light devices, some suggest, enhance blood flow, oxygen uptake and cell renewal in the skin, and activate collagen formation – an important goal for anti-aging. “The evidence is there,” states the dermatologist. “Although it’s not strong.” Regardless, with numerous products on the market, “we’re uncertain whether commercial devices replicate research conditions. Optimal treatment times are unknown, proper positioning requirements, if benefits outweigh potential risks. Numerous concerns persist.”

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 – even though, says Ho, “it’s commonly used in cosmetic clinics.” Individuals include it in their skincare practices, he says, though when purchasing home devices, “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

At the same time, in innovative scientific domains, researchers have been testing neural cells, revealing various pathways for light-enhanced cell function. “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 results appear unrealistic. However, scientific investigation has altered his perspective.

Chazot mostly works on developing drug treatments for neurodegenerative diseases, though twenty years earlier, a doctor developing photonic antiviral treatment consulted his scientific background. “He developed equipment for cellular and insect experiments,” he explains. “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.

Mitochondrial Impact and Cognitive Support

Growing data suggested infrared influenced energy-producing organelles. These organelles generate cellular energy, producing fuel for biological processes. “All human cells contain mitochondria, including the brain,” notes the researcher, who, as a neuroscientist, decided to focus the research on brain cells. “It has been shown that in humans this light therapy increases blood flow into the brain, which is always very good.”

Using 1070nm wavelength, energy organelles generate minimal reactive oxygen compounds. In low doses this substance, notes the scientist, “triggers guardian proteins that maintain organelle health, preserve cell function and eliminate damaged proteins.”

Such mechanisms indicate hope for cognitive disorders: oxidative protection, swelling control, and waste removal – autophagy being the process the cell uses to clear unwanted damaging proteins.

Ongoing Study Progress and Specialist Evaluations

Upon examining current studies on light therapy for dementia, he reports, approximately 400 participants enrolled in multiple trials, comprising his early research projects