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Light therapy is clearly enjoying a moment. There are now available light-emitting tools for everything from dermatological concerns and fine lines to aching tissues and oral inflammation, recently introduced is an oral care tool enhanced with small red light diodes, described by its makers as “a significant discovery for domestic dental hygiene.” Globally, the sector valued at $1bn last year is expected to increase to $1.8bn within the next decade. You can even go and sit in an infrared sauna, where instead of hot coals (real or electric) heating the air, the infrared radiation heats your body itself. Based on supporter testimonials, the experience resembles using an LED facial mask, enhancing collagen production, relaxing muscles, reducing swelling and chronic health conditions and potentially guarding against cognitive decline.

The Science and Skepticism

“It sounds a bit like witchcraft,” notes a Durham University professor, who has researched light therapy for two decades. Of course, we know light influences biological functions. Sunlight helps us make vitamin D, needed for bone health, immunity, muscles and more. Natural light synchronizes our biological clocks, additionally, stimulating neurotransmitter and hormone production during daytime, and signaling the body to slow down for nighttime. Daylight-simulating devices frequently help individuals with seasonal depression to boost low mood in winter. Clearly, light energy is essential for optimal functioning.

Different Light Modalities

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. During advanced medical investigations, including research on infrared’s impact on neural cells, finding the right frequency is key. Photons represent electromagnetic waves, 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, the highest energy of those being invisible ultraviolet, 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 to treat chronic skin conditions such as eczema, psoriasis and vitiligo. It works on the immune system within cells, “and dampens down inflammation,” notes a skin specialist. “There’s lots of evidence for phototherapy.” UVA penetrates skin more deeply than UVB, while the LEDs in consumer devices (which generally deliver red, infrared or blue light) “generally affect surface layers.”

Safety Considerations and Medical Oversight

UVB radiation effects, such as burning or tanning, are well known but in medical devices the light is delivered in a “narrow-band” form – signifying focused frequency bands – which minimises the risks. “Treatment is monitored by medical staff, thus exposure is controlled,” explains the dermatologist. And crucially, the devices are tuned by qualified personnel, “to guarantee appropriate wavelength emission – unlike in tanning salons, where regulations may be lax, and we don’t really know what wavelengths are being used.”

Consumer Devices and Evidence Gaps

Colored light diodes, he notes, “don’t have strong medical applications, though they might benefit some issues.” Red LEDs, it is proposed, help boost blood circulation, oxygen absorption and skin cell regeneration, and promote collagen synthesis – a primary objective in youth preservation. “Research exists,” states the dermatologist. “But it’s not conclusive.” In any case, 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. Many uncertainties remain.”

Targeted Uses and Expert Opinions

Early blue-light applications focused on skin microbes, microorganisms connected to breakouts. Scientific backing remains inadequate for regular prescription – although, explains the specialist, “it’s frequently employed in beauty centers.” Some of his patients use it as part of their routine, he observes, however for consumer products, “we recommend careful testing and security confirmation. If it’s not medically certified, oversight remains ambiguous.”

Innovative Investigations and Molecular Effects

Meanwhile, in innovative scientific domains, researchers have been testing neural cells, identifying a number of ways in which infrared can boost cellular health. “Virtually all experiments with specific wavelengths showed beneficial and safeguarding effects,” he says. The numerous reported benefits have generated doubt regarding phototherapy – that results appear unrealistic. But his research has thoroughly changed his mind in that respect.

The researcher primarily focuses on pharmaceutical solutions for brain disorders, but over 20 years ago, a doctor developing photonic antiviral treatment consulted his scientific background. “He developed equipment for cellular and insect experiments,” he says. “I remained doubtful. The specific wavelength measured approximately 1070nm, that many assumed was biologically inert.”

What it did have going for it, though, was its ability to transmit through aqueous environments, allowing substantial bodily penetration.

Mitochondrial Effects and Brain Health

Additional research indicated infrared affected cellular mitochondria. Mitochondria produce ATP for cell function, generating energy for them to function. “All human cells contain mitochondria, even within brain tissue,” says Chazot, who, as a neuroscientist, decided to focus the research on brain cells. “Research confirms improved brain blood flow with phototherapy, which is consistently beneficial.”

With specific frequency application, mitochondria also produce a small amount of a molecule known as reactive oxygen species. In low doses this substance, explains the expert, “triggers guardian proteins that maintain organelle health, preserve cell function and eliminate damaged proteins.”

Such mechanisms indicate hope for cognitive disorders: oxidative protection, anti-inflammatory, and pro-autophagy – self-digestion mechanisms eliminating harmful elements.

Present Investigation Status and Expert Assessments

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