Light therapy is clearly enjoying a surge in popularity. There are now available light-emitting tools targeting issues like skin conditions and wrinkles to sore muscles and oral inflammation, the newest innovation is an oral care tool outfitted with tiny red LEDs, described by its makers as “a breakthrough for domestic dental hygiene.” Worldwide, 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, that employ light waves rather than traditional heat sources, the thermal energy targets your tissues immediately. Based on supporter testimonials, the experience resembles using an LED facial mask, enhancing collagen production, easing muscle tension, relieving inflammation and long-term ailments as well as supporting brain health.
“It sounds a bit like witchcraft,” says Paul Chazot, a scientist who has studied phototherapy extensively. Of course, certain impacts of light on human physiology are proven. Sunlight enables vitamin D production, crucial for strong bones, immune defense, and tissue repair. Sunlight regulates our circadian rhythms, additionally, activating brain chemicals and hormonal responses in daylight, and signaling the body to slow down for nighttime. Sunlight-imitating lamps frequently help individuals with seasonal depression to boost low mood in winter. Clearly, light energy is essential for optimal functioning.
Whereas seasonal affective disorder devices typically employ blue-range light, 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. Light is a form of electromagnetic radiation, which runs the spectrum from the lowest-energy, longest wavelengths (radio waves) to short-wavelength gamma rays. Light-based treatment employs mid-spectrum wavelengths, with ultraviolet representing the higher energy invisible light, then the visible spectrum we perceive as colors 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,” notes a dermatology expert. “There’s lots of evidence for phototherapy.” UVA penetrates skin more deeply than UVB, while the LEDs in consumer devices (usually producing colored light emissions) “tend to be a bit more superficial.”
Potential UVB consequences, including sunburn or skin darkening, are recognized but medical equipment uses controlled narrow-band delivery – meaning smaller wavelengths – which decreases danger. “Treatment is monitored by medical staff, thus exposure is controlled,” notes the specialist. Essentially, the light sources are adjusted by technical experts, “to guarantee appropriate wavelength emission – different from beauty salons, where it’s a bit unregulated, and we don’t really know what wavelengths are being used.”
Red and blue LEDs, he says, “aren’t really used in the medical sense, but could assist with specific concerns.” Red wavelength therapy, proponents claim, enhance blood flow, oxygen utilization and cell renewal in the skin, and promote collagen synthesis – a key aspiration in anti-ageing effects. “Studies are available,” says Ho. “But it’s not conclusive.” Regardless, with numerous products on the market, “we don’t know whether or not the lights emitted are reflective of the research that has been done. Optimal treatment times are unknown, how close the lights should be to the skin, if benefits outweigh potential risks. Many uncertainties remain.”
Early blue-light applications focused on skin microbes, microorganisms connected to breakouts. Research support isn’t sufficient for standard medical recommendation – although, explains the specialist, “it’s commonly used in cosmetic clinics.” Certain patients incorporate it into their regimen, he mentions, however for consumer products, “we just tell them to try it carefully and to make sure it has been assessed for safety. Unless it’s a medical device, the regulation is a bit grey.”
At the same time, in advanced research areas, scientists have been studying cerebral tissue, identifying a number of ways in which infrared can boost cellular health. “Nearly every test with precise light frequencies demonstrated advantageous outcomes,” 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. But his research has thoroughly changed his mind in that respect.
Chazot mostly works on developing drug treatments for neurodegenerative diseases, but over 20 years ago, a GP who was developing an antiviral light treatment for cold sores sought his expertise as a biologist. “He created some devices so that we could work with them with cells and with fruit flies,” he explains. “I remained doubtful. It was an unusual wavelength of about 1070 nanometres, that many assumed was biologically inert.”
The advantage it possessed, nevertheless, was its ability to transmit through aqueous environments, meaning it could penetrate the body more deeply.
More evidence was emerging at the time that infrared light targeted the mitochondria in cells. These organelles generate cellular energy, producing fuel for biological processes. “All human cells contain mitochondria, including the brain,” notes the researcher, who, as a neuroscientist, decided to focus the research on brain cells. “Studies demonstrate enhanced cerebral circulation with light treatment, which is always very good.”
Using 1070nm wavelength, mitochondria also produce a small amount of a molecule known as reactive oxygen species. In low doses this substance, notes the scientist, “activates protective proteins that safeguard mitochondria, look after your cells and also deal with the unwanted proteins.”
All of these mechanisms appear promising for treating a brain disease: antioxidant, swelling control, and pro-autophagy – autophagy being the process the cell uses to clear unwanted damaging proteins.
When recently reviewing 1070nm research for cognitive decline, he reports, about 400 people were taking part in four studies, including his own initial clinical trials in the US
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