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Light therapy is certainly having a moment. There are now available glowing gadgets targeting issues like complexion problems and aging signs to muscle pain and periodontal issues, the newest innovation is a toothbrush enhanced with miniature red light sources, promoted by the creators as “a breakthrough in personal mouth health.” Worldwide, the industry reached $1 billion in 2024 and is forecast to expand to $1.8 billion by 2035. There are even infrared saunas available, where instead of hot coals (real or electric) heating the air, the thermal energy targets your tissues immediately. Based on supporter testimonials, the experience resembles using an LED facial mask, stimulating skin elasticity, soothing sore muscles, relieving inflammation and persistent medical issues and potentially guarding against cognitive decline.

Understanding the Evidence

“It appears somewhat mystical,” observes Paul Chazot, professor in neuroscience at Durham University and a convert to the value of light therapy. Certainly, some of light’s effects on our bodies are well established. Sunlight enables vitamin D production, needed for bone health, immunity, muscles and more. Sunlight regulates our circadian rhythms, as well, activating brain chemicals and hormonal responses in daylight, and winding down bodily functions for sleep as it fades into night. Daylight-simulating devices are a common remedy for people with seasonal affective disorder (Sad) to boost low mood in winter. Undoubtedly, light plays a vital role in human health.

Types of Light Therapy

Although mood lamps generally utilize blue-spectrum frequencies, most other light therapy devices deploy red or infrared light. During advanced medical investigations, such as Chazot’s investigations into the effects of infrared on brain cells, identifying the optimal wavelength is crucial. Photons represent electromagnetic waves, extending from long-wavelength radiation to short-wavelength gamma rays. Therapeutic light application utilizes intermediate light frequencies, the highest energy of those being invisible ultraviolet, followed by visible light encompassing rainbow colors and then infrared (which we can see with night-vision goggles).

Dermatologists have utilized UV therapy for extensive periods for addressing long-term dermatological issues like vitiligo. It modulates intracellular immune mechanisms, “and reduces inflammatory processes,” says a skin specialist. “Considerable data validates 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) “tend to be a bit more superficial.”

Risk Assessment and Professional Supervision

The side-effects of UVB exposure, including sunburn or skin darkening, are well known but in medical devices the light is delivered in a “narrow-band” form – indicating limited wavelength spectrum – that reduces potential hazards. “Treatment is monitored by medical staff, so the dosage is monitored,” notes the specialist. And crucially, the lightbulbs are calibrated by medical technicians, “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.”

Consumer Devices and Evidence Gaps

Red and blue light sources, he notes, “aren’t really used in the medical sense, though they might benefit some issues.” Red wavelength therapy, proponents claim, improve circulatory function, oxygen absorption and skin cell regeneration, and stimulate collagen production – an important goal for anti-aging. “Studies are available,” states the dermatologist. “But it’s not conclusive.” Nevertheless, with numerous products on the market, “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.”

Treatment Areas and Specialist Views

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 – even though, explains the specialist, “it’s frequently employed in beauty centers.” Some of his patients use it as part of their routine, he mentions, though when purchasing home devices, “we recommend careful testing and security confirmation. Without proper medical classification, the regulation is a bit grey.”

Advanced Research and Cellular Mechanisms

At the same time, in a far-flung field of pioneering medical science, 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 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.

The scientist mainly develops medications for neurological conditions, however two decades past, a physician creating light-based cold sore therapy requested his biological knowledge. “He developed equipment for cellular and insect experiments,” he explains. “I remained doubtful. It was an unusual wavelength of about 1070 nanometres, which most thought had no biological effect.”

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

Mitochondrial Effects and Brain Health

More evidence was emerging at the time that infrared light targeted the mitochondria in cells. Mitochondria are the powerhouses of cells, generating energy for them to function. “Mitochondria exist throughout the body, particularly in neural cells,” says Chazot, who, as a neuroscientist, decided to focus the research on brain cells. “Research confirms improved brain blood flow with phototherapy, which is consistently beneficial.”

Using 1070nm wavelength, energy organelles generate minimal reactive oxygen compounds. In low doses this substance, says Chazot, “triggers guardian proteins that maintain organelle health, protect cellular integrity and manage defective proteins.”

All of these mechanisms appear promising for treating a brain disease: free radical neutralization, inflammation reduction, and pro-autophagy – self-digestion mechanisms eliminating harmful elements.

Current Research Status and Professional Opinions

The last time Chazot checked the literature on using the 1070 wavelength on human dementia patients, he says, several hundred individuals participated in various investigations, comprising his early research projects