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Light therapy is clearly enjoying a moment. There are now available glowing gadgets for everything from dermatological concerns and fine lines to muscle pain and gum disease, the latest being a dental hygiene device enhanced with miniature red light sources, described by its makers as “a breakthrough in at-home oral care.” Internationally, 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, your body is warmed directly by infrared light. Based on supporter testimonials, it feels similar to a full-body light therapy session, boosting skin collagen, soothing sore muscles, relieving inflammation and chronic health conditions as well as supporting brain health.

The Science and Skepticism

“It feels almost magical,” notes Paul Chazot, who has researched light therapy for two decades. Of course, we know light influences biological functions. Sunlight enables vitamin D production, needed for bone health, immunity, muscles and more. Light exposure controls our sleep-wake cycles, additionally, stimulating neurotransmitter and hormone production during daytime, and winding down bodily functions for sleep as it fades into night. Artificial sun lamps are standard treatment for winter mood disorders to combat seasonal emotional slumps. 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, the majority of phototherapy tools use red or near-infrared wavelengths. During advanced medical investigations, like examinations of infrared influence on cerebral tissue, 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 employs mid-spectrum wavelengths, the highest energy of those being invisible ultraviolet, then visible light (all the colours we see in a rainbow) and then infrared (which we can see with night-vision goggles).

Ultraviolet treatment has been employed by skin specialists for decades for addressing long-term dermatological issues like vitiligo. It works on the immune system within cells, “and suppresses swelling,” explains a skin specialist. “Considerable data validates phototherapy.” UVA penetrates skin more deeply than UVB, in contrast to LEDs in commercial products (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 recognized but medical equipment uses controlled narrow-band delivery – indicating limited wavelength spectrum – that reduces potential hazards. “Treatment is monitored by medical staff, meaning intensity is regulated,” notes the specialist. And crucially, the devices are tuned by qualified personnel, “to confirm suitable light frequency output – as opposed to commercial tanning facilities, where it’s a bit unregulated, and wavelength accuracy isn’t verified.”

Consumer Devices and Evidence Gaps

Red and blue light sources, he explains, “don’t have strong medical applications, though they might benefit some issues.” Red LEDs, it is proposed, enhance blood flow, oxygen absorption and cell renewal in the skin, and activate collagen formation – a primary objective in youth preservation. “Studies are available,” says Ho. “But it’s not conclusive.” Regardless, amid the sea of devices now available, “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, how close the lights should be to the skin, if benefits outweigh potential risks. Numerous concerns persist.”

Specific Applications and Professional Perspectives

Initial blue-light devices addressed acne bacteria, a microbe associated with acne. The evidence for its efficacy isn’t strong enough for it to be routinely prescribed by doctors – although, says Ho, “it’s commonly used in cosmetic clinics.” Certain patients incorporate it into their regimen, he observes, though when purchasing home devices, “we recommend careful testing and security confirmation. Without proper medical classification, standards are somewhat unclear.”

Advanced Research and Cellular Mechanisms

Simultaneously, in innovative scientific domains, scientists have been studying cerebral tissue, identifying a number of ways in which infrared can boost cellular health. “Virtually all experiments with specific wavelengths showed beneficial and safeguarding effects,” he reports. 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.

The scientist mainly develops medications for neurological conditions, but over 20 years ago, a physician creating light-based cold sore therapy requested his biological knowledge. “He designed tools for biological testing,” he says. “I was quite suspicious. The specific wavelength measured approximately 1070nm, that many assumed was biologically inert.”

The advantage it possessed, however, was its ability to transmit through aqueous environments, meaning it could penetrate the body more deeply.

Mitochondrial Effects and Brain Health

Additional research indicated infrared affected cellular mitochondria. Mitochondria produce ATP for cell function, producing fuel for biological processes. “Mitochondria exist throughout the body, even within brain tissue,” says Chazot, who prioritized neurological investigations. “It has been shown that in humans this light therapy increases blood flow into the brain, which is always very good.”

Using 1070nm wavelength, mitochondria also produce a small amount of a molecule known as reactive oxygen species. In limited quantities these molecules, explains the expert, “activates protective proteins that safeguard mitochondria, look after your cells and also deal with the unwanted proteins.”

These processes show potential for neurological conditions: oxidative protection, anti-inflammatory, and waste removal – 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 reports, approximately 400 participants enrolled in multiple trials, including his own initial clinical trials in the US