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Light therapy is certainly having a moment. Consumers can purchase illuminated devices designed to address dermatological concerns and fine lines to sore muscles and gum disease, the latest being an oral care tool outfitted with miniature red light sources, described by its makers as “a major advance in at-home oral care.” Worldwide, the industry reached $1 billion in 2024 and is forecast to expand to $1.8 billion 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. As claimed by enthusiasts, the experience resembles using an LED facial mask, boosting skin collagen, soothing sore muscles, reducing swelling and chronic health conditions while protecting against dementia.

Research and Reservations

“It appears somewhat mystical,” notes Paul Chazot, a scientist who has studied phototherapy extensively. Certainly, certain impacts of light on human physiology are proven. Sunlight enables vitamin D production, needed for bone health, immunity, muscles and more. Natural light synchronizes our biological clocks, too, triggering the release of neurochemicals and hormones while we are awake, and winding down bodily functions for sleep as it fades into night. Artificial sun lamps are standard treatment for winter mood disorders to boost low mood in winter. So there’s no doubt we need light energy to function well.

Various Phototherapy Approaches

Whereas seasonal affective disorder devices typically employ blue-range light, most other light therapy devices deploy red or infrared light. During advanced medical investigations, such as Chazot’s investigations into the effects of infrared on brain cells, finding the right frequency is key. Photons represent electromagnetic waves, spanning from low-energy radio waves to high-energy gamma radiation. Phototherapy, or light therapy uses wavelengths around the middle of this spectrum, the highest energy of those being invisible ultraviolet, followed by visible light encompassing rainbow colors and then infrared (which we can see with night-vision goggles).

Ultraviolet treatment has been employed by skin specialists for decades to manage persistent skin disorders including eczema and psoriasis. It modulates intracellular immune mechanisms, “and suppresses swelling,” explains Dr Bernard Ho. “Considerable data validates phototherapy.” UVA goes deeper into the skin than UVB, while the LEDs in consumer devices (which generally deliver red, infrared or blue light) “typically have shallower penetration.”

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 – indicating limited wavelength spectrum – which decreases danger. “It’s supervised by a healthcare professional, so the dosage is monitored,” says Ho. And crucially, the lightbulbs are calibrated by medical technicians, “to guarantee appropriate wavelength emission – different from beauty salons, where regulations may be lax, and we don’t really know what wavelengths are being used.”

Home Devices and Scientific Uncertainty

Red and blue LEDs, he explains, “don’t have strong medical applications, though they might benefit some issues.” Red LEDs, it is proposed, improve circulatory function, oxygen utilization and dermal rejuvenation, and stimulate collagen production – an important goal for anti-aging. “Studies are available,” comments the expert. “Although it’s not strong.” Regardless, 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. Optimal treatment times are unknown, how close the lights should be to the skin, the risk-benefit ratio. Numerous concerns persist.”

Treatment Areas and Specialist Views

Initial blue-light devices addressed acne bacteria, a microbe associated with acne. Scientific backing remains inadequate for regular prescription – despite the fact that, notes the dermatologist, “it’s often seen in medical spas or aesthetics practices.” Certain patients incorporate it into their regimen, he says, but if they’re buying a device for home use, “we advise cautious experimentation and safety verification. If it’s not medically certified, oversight remains ambiguous.”

Advanced Research and Cellular Mechanisms

Meanwhile, in advanced research areas, 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 states. The numerous reported benefits have generated doubt regarding phototherapy – that it’s too good to be true. However, scientific investigation has altered his perspective.

Chazot mostly works on developing drug treatments for neurodegenerative diseases, but over 20 years ago, a doctor developing photonic antiviral treatment consulted his scientific background. “He designed tools for biological testing,” he explains. “I was pretty sceptical. This particular frequency was around 1070 nanometers, that many assumed was biologically inert.”

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

Mitochondrial Effects and Brain Health

More evidence was emerging at the time that infrared light targeted the mitochondria in cells. Mitochondria are the powerhouses of cells, producing fuel for biological processes. “All human cells contain mitochondria, particularly in neural cells,” says Chazot, who, as a neuroscientist, decided to focus the research on brain cells. “Research confirms improved brain blood flow with phototherapy, which is generally advantageous.”

Using 1070nm wavelength, mitochondria also produce a small amount of a molecule known as reactive oxygen species. At controlled levels these compounds, says Chazot, “activates protective proteins that safeguard mitochondria, protect cellular integrity and manage defective proteins.”

All of these mechanisms appear promising for treating a brain disease: antioxidant, anti-inflammatory, and pro-autophagy – self-digestion mechanisms eliminating harmful elements.

Ongoing Study Progress and Specialist Evaluations

When recently reviewing 1070nm research for cognitive decline, he reports, approximately 400 participants enrolled in multiple trials, including his own initial clinical trials in the US