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Light therapy is clearly enjoying a surge in popularity. You can now buy illuminated devices targeting issues like dermatological concerns and fine lines to sore muscles and oral inflammation, the latest being a dental hygiene device enhanced with miniature red light sources, described by its makers as “a breakthrough in personal mouth health.” Internationally, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. You can even go and sit in an infrared sauna, that employ light waves rather than traditional heat sources, the infrared radiation heats your body itself. As claimed by enthusiasts, the experience resembles using an LED facial mask, stimulating skin elasticity, easing muscle tension, alleviating inflammatory responses and persistent medical issues and potentially guarding against cognitive decline.

Understanding the Evidence

“It feels almost magical,” notes a neuroscience expert, who has researched light therapy for two decades. Naturally, some of light’s effects on our bodies are well established. Sunlight helps us make vitamin D, crucial for strong bones, immune defense, and tissue repair. Natural light synchronizes our biological clocks, additionally, stimulating neurotransmitter and hormone production during daytime, and winding down bodily functions for sleep as it fades into night. Sunlight-imitating lamps are a common remedy for people with seasonal affective disorder (Sad) to boost low mood in winter. Undoubtedly, light plays a vital role in human health.

Various Phototherapy Approaches

While Sad lamps tend to use a mixture of light frequencies from the blue end of the spectrum, 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, determining the precise frequency is essential. Light constitutes electromagnetic energy, which runs the spectrum from the lowest-energy, longest wavelengths (radio waves) to high-energy gamma radiation. Phototherapy, or light therapy utilizes intermediate light frequencies, including invisible ultraviolet radiation, followed by visible light encompassing rainbow colors and infrared light visible through night vision technology.

Ultraviolet treatment has been employed by skin specialists for decades to treat chronic skin conditions such as eczema, psoriasis and vitiligo. It modulates intracellular immune mechanisms, “and dampens down inflammation,” says a dermatology expert. “Substantial research supports light therapy.” UVA reaches deeper skin layers compared to UVB, whereas the LEDs we see on consumer light-therapy devices (typically emitting red, infrared or blue wavelengths) “tend to be a bit more superficial.”

Safety Protocols and Medical Guidance

The side-effects of UVB exposure, such as burning or tanning, are understood but clinical devices employ restricted wavelength ranges – signifying focused frequency bands – which minimises the risks. “Therapy is overseen by qualified practitioners, thus exposure is controlled,” says Ho. And crucially, the devices are tuned by qualified personnel, “to guarantee appropriate wavelength emission – unlike in tanning salons, where regulations may be lax, and emission spectra aren’t confirmed.”

Commercial Products and Research Limitations

Colored light diodes, he says, “aren’t typically employed clinically, but could assist with specific concerns.” Red light devices, some suggest, enhance blood flow, oxygen uptake and skin cell regeneration, and stimulate collagen production – a key aspiration in anti-ageing effects. “The evidence is there,” says Ho. “Although it’s not strong.” Regardless, given the plethora of available tools, “we don’t know whether or not the lights emitted are reflective of the research that has been done. We don’t know the duration, ideal distance from skin surface, whether or not that will increase the risk versus the benefit. There are lots of questions.”

Specific Applications and Professional Perspectives

One of the earliest blue-light products targeted Cutibacterium acnes, a microbe associated with acne. Scientific backing remains inadequate for regular prescription – even though, explains the specialist, “it’s often seen in medical spas or aesthetics practices.” Individuals include it in their skincare practices, he observes, but if they’re buying a device for home use, “we recommend careful testing and security confirmation. Unless it’s a medical device, oversight remains ambiguous.”

Advanced Research and Cellular Mechanisms

At the same time, in a far-flung field of pioneering medical science, Chazot has been experimenting with brain cells, revealing various pathways for light-enhanced cell function. “Nearly every test with precise light frequencies demonstrated advantageous outcomes,” 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. Yet, experimental evidence has transformed his viewpoint.

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 says. “I was quite suspicious. The specific wavelength measured approximately 1070nm, that many assumed was biologically inert.”

Its beneficial characteristic, however, was its ability to transmit through aqueous environments, allowing substantial bodily penetration.

Cellular Energy and Neurological Benefits

Growing data suggested infrared influenced energy-producing organelles. Mitochondria are the powerhouses of cells, generating energy for them to function. “All human cells contain mitochondria, including the brain,” explains the neuroscientist, who, as a neuroscientist, decided to focus the research on brain cells. “Studies demonstrate enhanced cerebral circulation with light treatment, which is consistently beneficial.”

Using 1070nm wavelength, cellular power plants create limited oxidative molecules. In low doses this substance, says Chazot, “triggers guardian proteins that maintain organelle health, protect cellular integrity and manage defective proteins.”

Such mechanisms indicate hope for cognitive disorders: antioxidant, swelling control, and waste removal – autophagy representing cellular waste disposal.

Ongoing Study Progress and Specialist Evaluations

When recently reviewing 1070nm research for cognitive decline, he states, several hundred individuals participated in various investigations, including his own initial clinical trials in the US