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Phototherapy is certainly having a wave of attention. There are now available light-emitting tools for everything from skin conditions and wrinkles to sore muscles and oral inflammation, recently introduced is a toothbrush enhanced with small red light diodes, promoted by the creators as “a major advance for domestic dental hygiene.” Internationally, 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. Based on supporter testimonials, it’s like bathing in one of those LED-lit beauty masks, stimulating skin elasticity, easing muscle tension, reducing swelling and chronic health conditions while protecting against dementia.

Understanding the Evidence

“It appears somewhat mystical,” notes Paul Chazot, who has researched light therapy for two decades. Of course, certain impacts of light on human physiology are proven. Sunlight enables vitamin D production, needed for bone health, immunity, muscles and more. Light exposure controls our sleep-wake cycles, too, stimulating neurotransmitter and hormone production during daytime, and preparing the body for rest as darkness falls. Daylight-simulating devices are a common remedy for people with seasonal affective disorder (Sad) to elevate spirits during colder months. So there’s no doubt we need light energy to function well.

Types of Light Therapy

Although mood lamps generally utilize blue-spectrum frequencies, the majority of phototherapy tools use red or near-infrared wavelengths. In serious clinical research, including research on infrared’s impact on neural cells, determining the precise frequency is essential. 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, followed by visible light encompassing rainbow colors and infrared light visible through night vision technology.

Ultraviolet treatment has been employed by skin specialists for decades to treat chronic skin conditions such as eczema, psoriasis and vitiligo. It affects cellular immune responses, “and reduces inflammatory processes,” notes a dermatology expert. “There’s lots of evidence for phototherapy.” UVA reaches deeper skin layers compared to UVB, whereas the LEDs we see on consumer light-therapy devices (typically emitting red, infrared or blue wavelengths) “typically have shallower penetration.”

Safety Protocols and Medical Guidance

The side-effects of UVB exposure, like erythema or pigmentation, are well known but in medical devices the light is delivered in a “narrow-band” form – signifying focused frequency bands – which decreases danger. “Treatment is monitored by medical staff, meaning intensity is regulated,” says Ho. And crucially, the devices are tuned by qualified personnel, “to ensure that the wavelength that’s being delivered is fit for purpose – 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 light sources, he explains, “don’t have strong medical applications, but could assist with specific concerns.” Red LEDs, it is proposed, help boost blood circulation, oxygen uptake and dermal rejuvenation, and promote collagen synthesis – a key aspiration in anti-ageing effects. “Studies are available,” comments the expert. “Although it’s not strong.” Nevertheless, 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.”

Targeted Uses and Expert Opinions

Early blue-light applications focused on skin microbes, a microbe associated with acne. The evidence for its efficacy isn’t strong enough for it to be routinely prescribed by doctors – despite the fact that, says Ho, “it’s commonly used in cosmetic clinics.” Certain patients incorporate it into their regimen, he mentions, but if they’re buying a device for home use, “we just tell them to try it carefully and to make sure it has been assessed for safety. Without proper medical classification, the regulation is a bit grey.”

Innovative Investigations and Molecular Effects

Meanwhile, in advanced research areas, researchers have been testing neural cells, 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 researcher primarily focuses on pharmaceutical solutions for brain disorders, though twenty years earlier, 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 nobody believed did anything biological.”

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

Mitochondrial Effects and Brain Health

Growing data suggested infrared influenced energy-producing organelles. Mitochondria produce ATP for cell function, producing fuel for biological processes. “All human cells contain mitochondria, particularly in neural cells,” says Chazot, who prioritized neurological investigations. “Studies demonstrate enhanced cerebral circulation with light treatment, which is consistently beneficial.”

Using 1070nm wavelength, cellular power plants create limited oxidative molecules. In limited quantities these molecules, notes the scientist, “activates protective proteins that safeguard mitochondria, preserve cell function and eliminate damaged proteins.”

Such mechanisms indicate hope for cognitive disorders: free radical neutralization, inflammation reduction, and pro-autophagy – autophagy being the process the cell uses to clear unwanted damaging proteins.

Present Investigation Status and Expert Assessments

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