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Light therapy is certainly having a surge in popularity. You can now buy illuminated devices targeting issues like dermatological concerns and fine lines to aching tissues and oral inflammation, the latest being a dental hygiene device equipped with tiny red LEDs, marketed by the company as “a breakthrough for domestic dental hygiene.” Globally, 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 infrared radiation heats your body itself. According to its devotees, it’s like bathing in one of those LED-lit beauty masks, enhancing collagen production, relaxing muscles, relieving inflammation and persistent medical issues as well as supporting brain health.

The Science and Skepticism

“It feels almost magical,” says Paul Chazot, a scientist who has studied phototherapy extensively. Naturally, some of light’s effects on our bodies are well established. Sunlight helps us make vitamin D, needed for bone health, immunity, muscles and more. Light exposure controls our sleep-wake cycles, additionally, activating brain chemicals and hormonal responses in daylight, and winding down bodily functions for sleep as it fades into night. Artificial sun lamps are standard treatment for winter mood disorders to elevate spirits during colder months. Undoubtedly, light plays a vital role in human health.

Various Phototherapy Approaches

Although mood lamps generally utilize blue-spectrum frequencies, most other light therapy devices deploy red or infrared light. In rigorous scientific studies, like examinations of infrared influence on cerebral tissue, finding the right frequency is key. Photons represent electromagnetic waves, which runs the spectrum from the lowest-energy, longest wavelengths (radio waves) to short-wavelength gamma rays. Therapeutic light application employs mid-spectrum wavelengths, with ultraviolet representing the higher energy invisible light, then the visible spectrum we perceive as colors and infrared light visible through night vision technology.

UV light has been used by medical dermatologists for many years to treat chronic skin conditions such as eczema, psoriasis and vitiligo. It modulates intracellular immune mechanisms, “and reduces inflammatory processes,” explains Dr Bernard Ho. “Substantial research supports light therapy.” UVA goes deeper into the skin than UVB, whereas the LEDs we see on consumer light-therapy devices (typically emitting red, infrared or blue wavelengths) “generally affect surface layers.”

Risk Assessment and Professional Supervision

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 – that reduces potential hazards. “It’s supervised by a healthcare professional, thus exposure is controlled,” notes the specialist. Most importantly, the lightbulbs are calibrated by medical technicians, “to ensure that the wavelength that’s being delivered is fit for purpose – unlike in tanning salons, where it’s a bit unregulated, and we don’t really know what wavelengths are being used.”

Consumer Devices and Evidence Gaps

Colored light diodes, he notes, “aren’t really used in the medical sense, though they might benefit some issues.” Red wavelength therapy, proponents claim, help boost blood circulation, oxygen utilization and cell renewal in the skin, and stimulate collagen production – an important goal for anti-aging. “Studies are available,” states the dermatologist. “But it’s not conclusive.” Regardless, amid the sea of devices now available, “we’re uncertain whether commercial devices replicate research conditions. Optimal treatment times are unknown, proper positioning requirements, the risk-benefit ratio. Many uncertainties remain.”

Treatment Areas and Specialist Views

Early blue-light applications focused on skin microbes, microorganisms connected to breakouts. Scientific backing remains inadequate for regular prescription – even though, says Ho, “it’s frequently employed in beauty centers.” Individuals include it in their skincare practices, he observes, however for consumer products, “we advise cautious experimentation and safety verification. Unless it’s a medical device, the regulation is a bit grey.”

Cutting-Edge Studies and Biological Processes

Meanwhile, in innovative scientific domains, researchers have been testing neural cells, revealing various pathways for light-enhanced cell function. “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. Yet, experimental evidence has transformed his viewpoint.

The researcher primarily focuses on pharmaceutical solutions for brain disorders, however two decades past, a physician creating light-based cold sore therapy requested his biological knowledge. “He developed equipment for cellular and insect experiments,” he recalls. “I was quite suspicious. 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.

Cellular Energy and Neurological Benefits

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. “Every cell in your body has mitochondria, including the brain,” explains the neuroscientist, who prioritized neurological investigations. “Research confirms improved brain blood flow with phototherapy, which is consistently beneficial.”

Using 1070nm wavelength, cellular power plants create limited oxidative molecules. In low doses this substance, says Chazot, “stimulates so-called chaperone proteins which look after your mitochondria, protect cellular integrity and manage defective proteins.”

All of these mechanisms appear promising for treating a brain disease: oxidative protection, swelling control, and pro-autophagy – autophagy representing cellular waste disposal.

Ongoing Study Progress and Specialist Evaluations

The last time Chazot checked the literature on using the 1070 wavelength on human dementia patients, he states, several hundred individuals participated in various investigations, comprising his early research projects