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Light-based treatment is clearly enjoying a surge in popularity. Consumers can purchase light-emitting tools designed to address dermatological concerns and fine lines to aching tissues and gum disease, the newest innovation is a dental hygiene device outfitted with tiny red LEDs, marketed by the company as “a significant discovery in at-home oral care.” 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, which use infrared light to warm the body directly, the thermal energy targets your tissues immediately. According to its devotees, it feels similar to a full-body light therapy session, boosting skin collagen, easing muscle tension, relieving inflammation and persistent medical issues while protecting against dementia.

Understanding the Evidence

“It feels almost magical,” observes a neuroscience expert, who has researched light therapy for two decades. Naturally, we know light influences biological functions. Sunlight enables vitamin D production, essential for skeletal strength, immune function, and muscular health. Natural light synchronizes our biological clocks, additionally, 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. Clearly, light energy is essential for optimal functioning.

Different Light Modalities

While Sad lamps tend to use a mixture of light frequencies from the blue end of the spectrum, the majority of phototherapy tools use red or near-infrared wavelengths. During advanced medical investigations, including research on infrared’s impact on neural cells, identifying the optimal wavelength is crucial. Light is a form of electromagnetic radiation, extending from long-wavelength radiation to high-energy gamma radiation. Phototherapy, or light therapy utilizes intermediate light frequencies, the highest energy of those being invisible ultraviolet, then visible light (all the colours we see in a rainbow) and finally infrared detectable with special equipment.

UV light has been used by medical dermatologists for many years to manage persistent skin disorders including eczema and psoriasis. It works on the immune system within cells, “and reduces inflammatory processes,” explains a skin specialist. “There’s lots of evidence for phototherapy.” UVA goes deeper into the skin than UVB, in contrast to LEDs in commercial products (typically emitting red, infrared or blue wavelengths) “tend to be a bit more superficial.”

Safety Considerations and Medical Oversight

UVB radiation effects, like erythema or pigmentation, are understood but clinical devices employ restricted wavelength ranges – indicating limited wavelength spectrum – which decreases danger. “Therapy is overseen by qualified practitioners, so the dosage is monitored,” says Ho. Essentially, the devices are tuned by qualified personnel, “to guarantee appropriate wavelength emission – unlike in tanning salons, where regulations may be lax, and wavelength accuracy isn’t verified.”

Commercial Products and Research Limitations

Red and blue LEDs, he explains, “aren’t really used in the medical sense, but they may help with certain conditions.” Red LEDs, it is proposed, enhance blood flow, oxygen uptake and cell renewal in the skin, and promote collagen synthesis – a key aspiration in anti-ageing effects. “Studies are available,” comments the expert. “However, it’s limited.” Regardless, given the plethora of available tools, “we’re uncertain whether commercial devices replicate research conditions. We don’t know the duration, proper positioning requirements, the risk-benefit ratio. Many uncertainties remain.”

Specific Applications and Professional Perspectives

Initial blue-light devices addressed acne bacteria, bacteria linked to pimples. Scientific backing remains inadequate for regular prescription – although, says Ho, “it’s often seen in medical spas or aesthetics practices.” Individuals include it in their skincare practices, he observes, though when purchasing home devices, “we advise cautious experimentation and safety verification. If it’s not medically certified, oversight remains ambiguous.”

Cutting-Edge Studies and Biological Processes

Meanwhile, in a far-flung field of pioneering medical science, scientists have been studying cerebral tissue, identifying a number of ways in which infrared can boost cellular health. “Pretty much everything I did with the light at that particular wavelength was positive and protective,” he says. 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.

Chazot mostly works on developing drug treatments for neurodegenerative diseases, but over 20 years ago, a physician creating light-based cold sore therapy requested his biological knowledge. “He developed equipment for cellular and insect experiments,” he recalls. “I remained doubtful. It was an unusual wavelength of about 1070 nanometres, that nobody believed did anything biological.”

The advantage it possessed, nevertheless, was that it travelled through water easily, allowing substantial bodily penetration.

Cellular Energy and Neurological Benefits

Additional research indicated infrared affected cellular mitochondria. Mitochondria are the powerhouses of cells, producing fuel for biological processes. “All human cells contain mitochondria, including the brain,” says Chazot, who, as a neuroscientist, decided to focus the research on brain cells. “Studies demonstrate enhanced cerebral circulation with light treatment, which is generally advantageous.”

Using 1070nm wavelength, cellular power plants create limited oxidative molecules. In limited quantities these molecules, explains the expert, “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: antioxidant, anti-inflammatory, and cellular cleanup – autophagy being the process the cell uses to clear unwanted damaging proteins.

Ongoing Study Progress and Specialist Evaluations

The last time Chazot checked the literature on using the 1070 wavelength on human dementia patients, he says, about 400 people were taking part in four studies, including his own initial clinical trials in the US