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Phototherapy is clearly enjoying a wave of attention. There are now available illuminated devices designed to address skin conditions and wrinkles to sore muscles and gum disease, the newest innovation is a dental hygiene device equipped with miniature red light sources, marketed by the company as “a breakthrough in personal mouth health.” Worldwide, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. There are even infrared saunas available, where instead of hot coals (real or electric) heating the air, your body is warmed directly by infrared light. As claimed by enthusiasts, it feels similar to a full-body light therapy session, boosting skin collagen, easing muscle tension, alleviating inflammatory responses and chronic health conditions while protecting against dementia.

The Science and Skepticism

“It feels almost magical,” says a neuroscience expert, a scientist who has studied phototherapy extensively. Of course, we know light influences biological functions. Our bodies produce vitamin D through sun exposure, crucial for strong bones, immune defense, and tissue repair. Sunlight regulates our circadian rhythms, as well, activating brain chemicals and hormonal responses in daylight, and preparing the body for rest as darkness falls. Sunlight-imitating lamps 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.

Various Phototherapy Approaches

While Sad lamps tend to use a mixture of light frequencies from the blue end of the spectrum, 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 is a form of electromagnetic radiation, extending from long-wavelength radiation to high-energy gamma radiation. Therapeutic light application employs mid-spectrum wavelengths, the highest energy of those being invisible ultraviolet, then the visible spectrum we perceive as colors and finally infrared detectable with special equipment.

Dermatologists have utilized UV therapy for extensive periods for addressing long-term dermatological issues like vitiligo. It modulates intracellular immune mechanisms, “and reduces inflammatory processes,” explains Dr Bernard Ho. “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) “typically have shallower penetration.”

Safety Protocols and Medical Guidance

Potential UVB consequences, 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 – which decreases danger. “It’s supervised by a healthcare professional, thus exposure is controlled,” says Ho. Most importantly, 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 emission spectra aren’t confirmed.”

Home Devices and Scientific Uncertainty

Red and blue light sources, he notes, “aren’t really used in the medical sense, but they may help with certain conditions.” Red light devices, some suggest, improve circulatory function, oxygen uptake and skin cell regeneration, and activate collagen formation – an important goal for anti-aging. “Research exists,” states the dermatologist. “However, it’s limited.” Regardless, given the plethora of available tools, “we’re uncertain whether commercial devices replicate research conditions. Appropriate exposure periods aren’t established, proper positioning requirements, if benefits outweigh potential risks. There are lots of questions.”

Treatment Areas and Specialist Views

One of the earliest blue-light products targeted Cutibacterium acnes, a microbe associated with acne. Research support isn’t sufficient for standard medical recommendation – despite the fact that, explains the specialist, “it’s commonly used in cosmetic clinics.” Individuals include it in their skincare practices, he says, however for consumer products, “we just tell them to try it carefully and to make sure it has been assessed for safety. Without proper medical classification, oversight remains ambiguous.”

Advanced Research and Cellular Mechanisms

At the same time, in advanced research areas, scientists have been studying cerebral tissue, 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. The numerous reported benefits have generated doubt regarding phototherapy – 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 GP who was developing an antiviral light treatment for cold sores sought his expertise as a biologist. “He designed tools for biological testing,” he explains. “I remained doubtful. It was an unusual wavelength of about 1070 nanometres, that nobody believed did anything biological.”

The advantage it possessed, however, 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. Mitochondria produce ATP for cell function, generating energy for them to function. “All human cells contain mitochondria, particularly in neural cells,” explains the neuroscientist, who concentrated on cerebral applications. “Research confirms improved brain blood flow with phototherapy, which is always very good.”

With 1070 treatment, energy organelles generate minimal reactive oxygen compounds. At controlled levels these compounds, says Chazot, “triggers guardian proteins that maintain organelle health, protect cellular integrity and manage defective proteins.”

These processes show potential for neurological conditions: free radical neutralization, inflammation reduction, and waste removal – autophagy representing cellular waste disposal.

Current Research Status and Professional Opinions

The last time Chazot checked the literature on using the 1070 wavelength on human dementia patients, he says, about 400 people were taking part in four studies, including his own initial clinical trials in the US