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Phototherapy is certainly having a moment. You can now buy illuminated devices targeting issues like dermatological concerns and fine lines to aching tissues and gum disease, recently introduced is an oral care tool enhanced with tiny red LEDs, described by its makers as “a significant discovery 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, where instead of hot coals (real or electric) heating the air, your body is warmed directly by infrared light. Based on supporter testimonials, it feels similar to a full-body light therapy session, boosting skin collagen, relaxing muscles, relieving inflammation and chronic health conditions and potentially guarding against cognitive decline.

Understanding the Evidence

“It appears somewhat mystical,” says a Durham University professor, who has researched light therapy for two decades. Certainly, some of light’s effects on our bodies are well established. Our bodies produce vitamin D through sun exposure, essential for skeletal strength, immune function, and muscular health. Natural light synchronizes our biological clocks, additionally, stimulating neurotransmitter and hormone production during daytime, and preparing the body for rest as darkness falls. Daylight-simulating devices are a common remedy for people with seasonal affective disorder (Sad) to elevate spirits during colder months. Undoubtedly, light plays a vital role in human health.

Types of Light Therapy

Although mood lamps generally utilize blue-spectrum frequencies, the majority of phototherapy tools use red or near-infrared wavelengths. During advanced medical investigations, including research on infrared’s impact on neural cells, identifying the optimal wavelength is crucial. Light is a form of electromagnetic radiation, spanning from low-energy radio waves to the highest-energy (gamma waves). Therapeutic light application uses wavelengths around the middle of this spectrum, with ultraviolet representing the higher energy invisible light, then the visible spectrum we perceive as 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 affects cellular immune responses, “and suppresses swelling,” notes a skin specialist. “Substantial research supports light therapy.” UVA penetrates skin more deeply than UVB, in contrast to LEDs in commercial products (which generally deliver red, infrared or blue light) “generally affect surface layers.”

Safety Protocols and Medical Guidance

UVB radiation effects, including sunburn or skin darkening, are recognized but medical equipment uses controlled narrow-band delivery – indicating limited wavelength spectrum – which minimises the risks. “Treatment is monitored by medical staff, meaning intensity is regulated,” notes the specialist. And crucially, the light sources are adjusted by technical experts, “to confirm suitable light frequency output – unlike in tanning salons, where it’s a bit unregulated, and emission spectra aren’t confirmed.”

Commercial Products and Research Limitations

Colored light diodes, he notes, “aren’t typically employed clinically, though they might benefit some issues.” Red LEDs, it is proposed, help boost blood circulation, oxygen uptake and dermal rejuvenation, and promote collagen synthesis – a primary objective in youth preservation. “The evidence is there,” says Ho. “However, it’s limited.” Nevertheless, given the plethora of available tools, “it’s unclear if device outputs match study parameters. Appropriate exposure periods aren’t established, ideal distance from skin surface, whether or not that will increase the risk versus the benefit. Many uncertainties remain.”

Specific Applications and Professional Perspectives

Initial blue-light devices addressed acne bacteria, bacteria linked to pimples. Research support isn’t sufficient for standard medical recommendation – despite the fact that, explains the specialist, “it’s often seen in medical spas or aesthetics practices.” Certain patients incorporate it into their regimen, he says, however for consumer products, “we recommend careful testing and security confirmation. If it’s not medically certified, the regulation is a bit grey.”

Advanced Research and Cellular Mechanisms

At the same time, in innovative scientific domains, scientists have been studying cerebral tissue, revealing various pathways for light-enhanced cell function. “Virtually all experiments with specific wavelengths showed beneficial and safeguarding effects,” he reports. 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, though twenty years earlier, 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 was quite suspicious. The specific wavelength measured approximately 1070nm, that nobody believed did anything biological.”

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

Cellular Energy and Neurological Benefits

Growing data suggested infrared influenced energy-producing organelles. Mitochondria produce ATP for cell function, creating power for cellular operations. “All human cells contain mitochondria, particularly in neural cells,” explains the neuroscientist, who concentrated on cerebral applications. “It has been shown that in humans this light therapy increases blood flow into the brain, which is consistently beneficial.”

Using 1070nm wavelength, energy organelles generate minimal reactive oxygen compounds. In limited quantities these molecules, says Chazot, “activates protective proteins that safeguard mitochondria, preserve cell function and eliminate damaged proteins.”

All of these mechanisms appear promising for treating a brain disease: antioxidant, swelling control, and waste removal – self-digestion mechanisms eliminating harmful elements.

Current Research Status and Professional Opinions

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