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Light therapy is certainly having a moment. You can now buy illuminated devices for everything from complexion problems and aging signs to aching tissues and gum disease, recently introduced is a toothbrush enhanced with small red light diodes, described by its makers as “a major advance in at-home oral care.” Worldwide, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. You can even go and sit in an infrared sauna, which use infrared light to warm the body directly, the thermal energy targets your tissues immediately. As claimed by enthusiasts, it feels similar to a full-body light therapy session, boosting skin collagen, soothing sore muscles, relieving inflammation and chronic health conditions and potentially guarding against cognitive decline.

Understanding the Evidence

“It sounds a bit like witchcraft,” notes Paul Chazot, who has researched light therapy for two decades. Certainly, certain impacts of light on human physiology are proven. Our bodies produce vitamin D through sun exposure, needed for bone health, immunity, muscles and more. Natural light synchronizes our biological clocks, as well, stimulating neurotransmitter and hormone production during daytime, and preparing the body for rest as darkness falls. Sunlight-imitating lamps are a common remedy for people with seasonal affective disorder (Sad) to elevate spirits during colder months. Clearly, light energy is essential for optimal functioning.

Various Phototherapy Approaches

Whereas seasonal affective disorder devices typically employ blue-range light, consumer light therapy products mostly feature red and infrared emissions. During advanced medical investigations, like examinations of infrared influence on cerebral tissue, determining the precise frequency is essential. Light is a form of electromagnetic radiation, spanning from low-energy radio waves to high-energy gamma radiation. Light-based treatment employs mid-spectrum wavelengths, with ultraviolet representing the higher energy invisible light, followed by visible light encompassing rainbow colors and then infrared (which we can see with night-vision goggles).

UV light has been used by medical dermatologists for many years for addressing long-term dermatological issues like vitiligo. It affects cellular immune responses, “and dampens down inflammation,” says a skin specialist. “Considerable data validates phototherapy.” UVA reaches deeper skin layers compared to UVB, while the LEDs in consumer devices (usually producing colored light emissions) “tend to be a bit more superficial.”

Risk Assessment and Professional Supervision

Potential UVB consequences, like erythema or pigmentation, are recognized but medical equipment uses controlled narrow-band delivery – indicating limited wavelength spectrum – which decreases danger. “It’s supervised by a healthcare professional, thus exposure is controlled,” explains the dermatologist. Essentially, 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 we don’t really know what wavelengths are being used.”

Home Devices and Scientific Uncertainty

Red and blue LEDs, he says, “don’t have strong medical applications, but could assist with specific concerns.” Red LEDs, it is proposed, improve circulatory function, oxygen absorption and dermal rejuvenation, and promote collagen synthesis – a key aspiration in anti-ageing effects. “Studies are available,” states the dermatologist. “However, it’s limited.” Nevertheless, with numerous products on the market, “it’s unclear if device outputs match study parameters. Appropriate exposure periods aren’t established, ideal distance from skin surface, whether or not that will increase the risk versus the benefit. Numerous concerns persist.”

Treatment Areas and Specialist Views

Initial blue-light devices addressed acne bacteria, microorganisms connected to breakouts. The evidence for its efficacy isn’t strong enough for it to be routinely prescribed by doctors – although, notes the dermatologist, “it’s commonly used in cosmetic clinics.” 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, standards are somewhat unclear.”

Advanced Research and Cellular Mechanisms

Meanwhile, in advanced research areas, scientists have been studying cerebral tissue, discovering multiple mechanisms for infrared’s cellular benefits. “Virtually all experiments with specific wavelengths showed beneficial and safeguarding effects,” he states. 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 doctor developing photonic antiviral treatment consulted his scientific background. “He created some devices so that we could work with them with cells and with fruit flies,” he explains. “I was pretty sceptical. This particular frequency was around 1070 nanometers, that many assumed was biologically inert.”

What it did have going for it, nevertheless, was its ability to transmit through aqueous environments, enabling deeper tissue penetration.

Mitochondrial Effects and Brain Health

Additional research indicated infrared affected cellular mitochondria. Mitochondria produce ATP for cell function, creating power for cellular operations. “Mitochondria exist throughout the body, particularly in neural cells,” explains the neuroscientist, who, as a neuroscientist, decided to focus the research on brain cells. “Research confirms improved brain blood flow with phototherapy, which is always very good.”

With 1070 treatment, cellular power plants create limited oxidative molecules. At controlled levels these compounds, explains the expert, “triggers guardian proteins that maintain organelle health, preserve cell function and eliminate damaged proteins.”

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