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Light therapy is clearly enjoying a wave of attention. Consumers can purchase glowing gadgets targeting issues like skin conditions and wrinkles to muscle pain and periodontal issues, the latest being a dental hygiene device equipped with miniature red light sources, promoted by the creators as “a major advance for domestic dental hygiene.” Globally, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. Options include full-body infrared sauna sessions, which use infrared light to warm the body directly, your body is warmed directly by infrared light. As claimed by enthusiasts, the experience resembles using an LED facial mask, boosting skin collagen, soothing sore muscles, reducing swelling and long-term ailments while protecting against dementia.

Understanding the Evidence

“It appears somewhat mystical,” says Paul Chazot, who has researched light therapy for two decades. Certainly, certain impacts of light on human physiology are proven. Sunlight enables vitamin D production, essential for skeletal strength, immune function, and muscular health. Natural light synchronizes our biological clocks, too, stimulating neurotransmitter and hormone production during daytime, and signaling the body to slow down for nighttime. Sunlight-imitating lamps are standard treatment for winter mood disorders to boost low mood in winter. Clearly, light energy is essential for optimal functioning.

Various Phototherapy Approaches

Although mood lamps generally utilize blue-spectrum frequencies, the majority of phototherapy tools use red or near-infrared wavelengths. During advanced medical investigations, such as Chazot’s investigations into the effects of infrared on brain cells, identifying the optimal wavelength is crucial. Light is a form of electromagnetic radiation, spanning from low-energy radio waves to short-wavelength gamma rays. Light-based treatment uses wavelengths around the middle of this spectrum, the highest energy of those being invisible ultraviolet, followed by visible light encompassing rainbow colors and infrared light visible through night vision technology.

Dermatologists have utilized UV therapy for extensive periods to treat chronic skin conditions such as eczema, psoriasis and vitiligo. It works on the immune system within cells, “and suppresses swelling,” explains a skin specialist. “Substantial research supports light therapy.” UVA penetrates skin more deeply than UVB, whereas the LEDs we see on consumer light-therapy devices (typically emitting red, infrared or blue wavelengths) “generally affect surface layers.”

Risk Assessment and Professional Supervision

UVB radiation effects, such as burning or tanning, are understood but clinical devices employ restricted wavelength ranges – meaning smaller wavelengths – which decreases danger. “It’s supervised by a healthcare professional, so the dosage is monitored,” says Ho. And crucially, the devices are tuned by qualified personnel, “to confirm suitable light frequency output – different from beauty salons, where regulations may be lax, and wavelength accuracy isn’t verified.”

Home Devices and Scientific Uncertainty

Colored light diodes, he notes, “don’t have strong medical applications, though they might benefit some issues.” Red wavelength therapy, proponents claim, help boost blood circulation, oxygen absorption and dermal rejuvenation, and stimulate collagen production – a primary objective in youth preservation. “The evidence is there,” says Ho. “But it’s not conclusive.” Nevertheless, with numerous products on the market, “we don’t know whether or not the lights emitted are reflective of the research that has been done. Appropriate exposure periods aren’t established, proper positioning requirements, whether or not that will increase the risk versus the benefit. Many uncertainties remain.”

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 – although, says Ho, “it’s commonly used in cosmetic clinics.” Individuals include it in their skincare practices, he says, but if they’re buying a device for home use, “we advise cautious experimentation and safety verification. Without proper medical classification, standards are somewhat unclear.”

Cutting-Edge Studies and Biological Processes

Meanwhile, in a far-flung field of pioneering medical science, Chazot has been experimenting with brain cells, discovering multiple mechanisms for infrared’s cellular benefits. “Nearly every test with precise light frequencies demonstrated advantageous outcomes,” he reports. It is partly these many and varied positive effects on cellular health that have driven skepticism about light therapy – that it’s too good to be true. But his research has thoroughly changed his mind in that respect.

The researcher primarily focuses on pharmaceutical solutions for brain disorders, however two decades past, 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 recalls. “I remained doubtful. It was an unusual wavelength of about 1070 nanometres, which most thought had no biological effect.”

The advantage it possessed, however, was its efficient water penetration, meaning it could penetrate the body more deeply.

Mitochondrial Impact and Cognitive Support

Additional research indicated infrared affected cellular mitochondria. Mitochondria produce ATP for cell function, generating energy for them to function. “Mitochondria exist throughout the body, even within brain tissue,” says Chazot, 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 consistently beneficial.”

With specific frequency application, energy organelles generate minimal reactive oxygen compounds. At controlled levels these compounds, says Chazot, “stimulates so-called chaperone proteins which look after your mitochondria, preserve cell function and eliminate damaged proteins.”

Such mechanisms indicate hope for cognitive disorders: free radical neutralization, anti-inflammatory, and pro-autophagy – autophagy being the process the cell uses to clear unwanted damaging proteins.

Current Research Status and Professional Opinions

Upon examining current studies on light therapy for dementia, he states, about 400 people were taking part in four studies, incorporating his preliminary American studies