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Light-based treatment is clearly enjoying a moment. You can now buy illuminated devices for everything from skin conditions and wrinkles as well as aching tissues and periodontal issues, the newest innovation is a dental hygiene device equipped with small red light diodes, promoted by the creators 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. You can even go and sit in an infrared sauna, where instead of hot coals (real or electric) heating the air, the thermal energy targets your tissues immediately. According to its devotees, it’s like bathing in one of those LED-lit beauty masks, boosting skin collagen, relaxing muscles, reducing swelling and long-term ailments as well as supporting brain health.

The Science and Skepticism

“It sounds a bit like witchcraft,” says a Durham University professor, a scientist who has studied phototherapy extensively. Of course, some of light’s effects on our bodies are well established. Our bodies produce vitamin D through sun exposure, crucial for strong bones, immune defense, and tissue repair. Light exposure controls our sleep-wake cycles, too, 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 combat seasonal emotional slumps. So there’s no doubt we need light energy to function well.

Different Light Modalities

Whereas seasonal affective disorder devices typically employ blue-range light, consumer light therapy products mostly feature red and infrared emissions. In serious clinical research, such as Chazot’s investigations into the effects of infrared on brain cells, identifying the optimal wavelength is crucial. Photons represent electromagnetic waves, extending from long-wavelength radiation to short-wavelength gamma rays. Therapeutic light application employs mid-spectrum wavelengths, with ultraviolet representing the higher energy invisible light, then visible light (all the colours we see in a rainbow) and finally infrared detectable with special equipment.

Ultraviolet treatment has been employed by skin specialists for decades for addressing long-term dermatological issues like vitiligo. It modulates intracellular immune mechanisms, “and reduces inflammatory processes,” says Dr Bernard Ho. “Considerable data validates phototherapy.” UVA penetrates skin more deeply than UVB, whereas the LEDs we see on consumer light-therapy devices (usually producing colored light emissions) “generally affect surface layers.”

Safety Protocols and Medical Guidance

The side-effects of UVB exposure, including sunburn or skin darkening, are well known but in medical devices the light is delivered in a “narrow-band” form – indicating limited wavelength spectrum – which minimises the risks. “Treatment is monitored by medical staff, meaning intensity is regulated,” explains the dermatologist. And crucially, the light sources are adjusted by technical experts, “to ensure that the wavelength that’s being delivered is fit for purpose – different from beauty salons, where regulations may be lax, and wavelength accuracy isn’t verified.”

Home Devices and Scientific Uncertainty

Colored light diodes, he explains, “aren’t typically employed clinically, but they may help with certain conditions.” Red LEDs, it is proposed, help boost blood circulation, oxygen utilization and dermal rejuvenation, and stimulate collagen production – a key aspiration in anti-ageing effects. “The evidence is there,” says Ho. “But it’s not conclusive.” Nevertheless, amid the sea of devices now available, “we’re uncertain whether commercial devices replicate research conditions. We don’t know the duration, how close the lights should be to the skin, the risk-benefit ratio. Many uncertainties remain.”

Specific Applications and Professional Perspectives

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 often seen in medical spas or aesthetics practices.” Certain patients incorporate it into their regimen, he observes, however for consumer products, “we recommend careful testing and security confirmation. Unless it’s a medical device, standards are somewhat unclear.”

Advanced Research and Cellular Mechanisms

Meanwhile, in advanced research areas, Chazot has been experimenting with brain cells, identifying a number of ways in which infrared can boost cellular health. “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 claims seem exaggerated. Yet, experimental evidence has transformed his viewpoint.

The researcher primarily focuses on pharmaceutical solutions for brain disorders, though twenty years earlier, a physician creating light-based cold sore therapy requested his biological knowledge. “He designed tools for biological testing,” he recalls. “I remained doubtful. This particular frequency was around 1070 nanometers, that many assumed was biologically inert.”

Its beneficial characteristic, though, was that it travelled through water easily, enabling deeper tissue penetration.

Mitochondrial Impact and Cognitive Support

Additional research indicated infrared affected cellular mitochondria. Mitochondria are the powerhouses of cells, producing fuel for biological processes. “Mitochondria exist throughout the body, particularly in neural cells,” explains the neuroscientist, who concentrated on cerebral applications. “Research confirms improved brain blood flow with phototherapy, which is generally advantageous.”

With specific frequency application, energy organelles generate minimal reactive oxygen compounds. In limited quantities these molecules, notes the scientist, “triggers guardian proteins that maintain organelle health, preserve cell function and eliminate damaged proteins.”

All of these mechanisms appear promising for treating a brain disease: free radical neutralization, inflammation reduction, and pro-autophagy – autophagy representing cellular waste disposal.

Present Investigation Status and Expert Assessments

When recently reviewing 1070nm research for cognitive decline, he says, about 400 people were taking part in four studies, comprising his early research projects