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Light therapy is clearly enjoying a surge in popularity. Consumers can purchase glowing gadgets designed to address skin conditions and wrinkles to sore muscles and oral inflammation, the latest being an oral care tool equipped with small red light diodes, described by its makers as “a significant discovery 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, the infrared radiation heats your body itself. According to its devotees, it’s like bathing in one of those LED-lit beauty masks, boosting skin collagen, soothing sore muscles, reducing swelling and chronic health conditions while protecting against dementia.

The Science and Skepticism

“It sounds a bit like witchcraft,” notes a neuroscience expert, who has researched light therapy for two decades. Of course, we know light influences biological functions. Sunlight helps us make vitamin D, needed for bone health, immunity, muscles and more. Natural light synchronizes our biological clocks, additionally, activating brain chemicals and hormonal responses in daylight, and preparing the body for rest as darkness falls. Artificial sun lamps are standard treatment for winter mood disorders to boost low mood in winter. Clearly, light energy is essential for optimal functioning.

Various Phototherapy Approaches

While Sad lamps tend to use a mixture of light frequencies from the blue end of the spectrum, consumer light therapy products mostly feature red and infrared emissions. In rigorous scientific studies, including research on infrared’s impact on neural cells, determining the precise frequency is essential. Light is a form of electromagnetic radiation, spanning from low-energy radio waves to short-wavelength gamma rays. Therapeutic light application employs mid-spectrum wavelengths, 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 for addressing long-term dermatological issues like vitiligo. It affects cellular immune responses, “and dampens down inflammation,” says a skin specialist. “There’s lots of evidence for phototherapy.” UVA penetrates skin more deeply than UVB, whereas the LEDs we see on consumer light-therapy devices (typically emitting red, infrared or blue wavelengths) “generally affect surface layers.”

Safety Protocols and Medical Guidance

UVB radiation effects, like erythema or pigmentation, 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, thus exposure is controlled,” says Ho. And crucially, the light sources are adjusted by technical experts, “to confirm suitable light frequency output – different from beauty salons, where oversight might be limited, and we don’t really know what wavelengths are being used.”

Commercial Products and Research Limitations

Red and blue LEDs, he notes, “don’t have strong medical applications, though they might benefit some issues.” Red wavelength therapy, proponents claim, help boost blood circulation, oxygen utilization and skin cell regeneration, and promote collagen synthesis – a key aspiration in anti-ageing effects. “The evidence is there,” comments the expert. “Although it’s not strong.” Regardless, given the plethora of available tools, “we’re uncertain whether commercial devices replicate research conditions. We don’t know the duration, ideal distance from skin surface, the risk-benefit ratio. Many uncertainties remain.”

Targeted Uses and Expert Opinions

Initial blue-light devices addressed acne bacteria, microorganisms connected to breakouts. Research support isn’t sufficient for standard medical recommendation – even though, says Ho, “it’s often seen in medical spas or aesthetics practices.” Some of his patients use it as part of their routine, he observes, though when purchasing home devices, “we recommend careful testing and security confirmation. Without proper medical classification, the regulation is a bit grey.”

Cutting-Edge Studies and Biological Processes

Simultaneously, in innovative scientific domains, Chazot has been experimenting with brain cells, discovering multiple mechanisms for infrared’s cellular benefits. “Pretty much everything I did with the light at that particular wavelength was positive and protective,” he reports. The numerous reported benefits have generated doubt regarding phototherapy – that results appear unrealistic. But his research has thoroughly changed his mind in that respect.

The scientist mainly develops medications for neurological conditions, however two decades past, a GP who was developing an antiviral light treatment for cold sores sought his expertise as a biologist. “He designed tools for biological testing,” he explains. “I was quite suspicious. This particular frequency was around 1070 nanometers, that many assumed was biologically inert.”

Its beneficial characteristic, though, was its ability to transmit through aqueous environments, enabling deeper tissue penetration.

Mitochondrial Impact and Cognitive Support

Additional research indicated infrared affected cellular mitochondria. These organelles generate cellular energy, generating energy for them to function. “All human cells contain mitochondria, including the brain,” says Chazot, who, as a neuroscientist, decided to focus the research on brain cells. “It has been shown that in humans this light therapy increases blood flow into the brain, which is consistently beneficial.”

With 1070 treatment, mitochondria also produce a small amount of a molecule known as reactive oxygen species. In low doses this substance, says Chazot, “activates protective proteins that safeguard mitochondria, look after your cells and also deal with the unwanted proteins.”

Such mechanisms indicate hope for cognitive disorders: antioxidant, swelling control, and waste removal – autophagy being the process the cell uses to clear unwanted damaging proteins.

Ongoing Study Progress and Specialist Evaluations

Upon examining current studies on light therapy for dementia, he says, several hundred individuals participated in various investigations, including his own initial clinical trials in the US