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Phototherapy is clearly enjoying a wave of attention. There are now available light-emitting tools targeting issues like dermatological concerns and fine lines along with aching tissues and periodontal issues, recently introduced is a toothbrush outfitted with small red light diodes, promoted by the creators as “a significant discovery for domestic dental hygiene.” Globally, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. There are even infrared saunas available, where instead of hot coals (real or electric) heating the air, your body is warmed directly by infrared light. According to its devotees, the experience resembles using an LED facial mask, boosting skin collagen, easing muscle tension, reducing swelling and chronic health conditions while protecting against dementia.

Research and Reservations

“It sounds a bit like witchcraft,” says a Durham University professor, professor in neuroscience at Durham University and a convert to the value of light therapy. Certainly, we know light influences biological functions. Our bodies produce vitamin D through sun exposure, needed for bone health, immunity, muscles and more. Natural light synchronizes our biological clocks, too, stimulating neurotransmitter and hormone production during daytime, and signaling the body to slow down for nighttime. Daylight-simulating devices are a common remedy for people with seasonal affective disorder (Sad) to combat seasonal emotional slumps. So there’s no doubt we need light energy to function well.

Types of Light Therapy

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. During advanced medical investigations, like examinations of infrared influence on cerebral tissue, determining the precise frequency is essential. Light constitutes electromagnetic energy, which runs the spectrum from the lowest-energy, longest wavelengths (radio waves) to high-energy gamma radiation. Therapeutic light application utilizes intermediate light frequencies, the highest energy of those being invisible ultraviolet, then the visible spectrum we perceive as colors and finally infrared detectable with special equipment.

Ultraviolet treatment has been employed by skin specialists for decades to manage persistent skin disorders including eczema and psoriasis. It affects cellular immune responses, “and dampens down inflammation,” notes a skin specialist. “Considerable data validates phototherapy.” UVA goes deeper into the skin than UVB, in contrast to LEDs in commercial products (usually producing colored light emissions) “tend to be a bit more superficial.”

Safety Considerations and Medical Oversight

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 – indicating limited wavelength spectrum – that reduces potential hazards. “It’s supervised by a healthcare professional, thus exposure is controlled,” says Ho. Essentially, the light sources are adjusted by technical experts, “to ensure that the wavelength that’s being delivered is fit for purpose – different from beauty salons, where regulations may be lax, and emission spectra aren’t confirmed.”

Home Devices and Scientific Uncertainty

Red and blue LEDs, he says, “don’t have strong medical applications, but could assist with specific concerns.” Red wavelength therapy, proponents claim, help boost blood circulation, oxygen utilization and dermal rejuvenation, and promote collagen synthesis – an important goal for anti-aging. “Studies are available,” says Ho. “However, it’s limited.” Regardless, 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, ideal distance from skin surface, if benefits outweigh potential risks. Numerous concerns persist.”

Targeted Uses and Expert Opinions

One of the earliest blue-light products targeted Cutibacterium acnes, 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 often seen in medical spas or aesthetics practices.” 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. If it’s not medically certified, standards are somewhat unclear.”

Innovative Investigations and Molecular Effects

At the same time, in advanced research areas, researchers have been testing neural cells, identifying a number of ways in which infrared can boost cellular health. “Nearly every test with precise light frequencies demonstrated advantageous outcomes,” he says. The numerous reported benefits have generated doubt regarding phototherapy – that claims seem exaggerated. Yet, experimental evidence has transformed his viewpoint.

The scientist mainly develops medications for neurological conditions, though twenty years earlier, a physician creating light-based cold sore therapy requested his biological knowledge. “He designed tools for biological testing,” he says. “I was pretty sceptical. This particular frequency was around 1070 nanometers, that many assumed was biologically inert.”

What it did have going for it, though, was that it travelled through water easily, meaning it could penetrate the body more deeply.

Mitochondrial Impact and Cognitive Support

Additional research indicated infrared affected cellular mitochondria. Mitochondria are the powerhouses of cells, creating power for cellular operations. “All human cells contain mitochondria, particularly in neural cells,” 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 always very good.”

Using 1070nm wavelength, mitochondria also produce a small amount of a molecule known as reactive oxygen species. At controlled levels these compounds, notes the scientist, “triggers guardian proteins that maintain organelle health, 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 representing cellular waste disposal.

Ongoing Study Progress and Specialist Evaluations

When recently reviewing 1070nm research for cognitive decline, he says, several hundred individuals participated in various investigations, including his own initial clinical trials in the US