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Light therapy is certainly having a wave of attention. You can now buy light-emitting tools designed to address complexion problems and aging signs to muscle pain and periodontal issues, the newest innovation is a dental hygiene device enhanced with miniature red light sources, promoted by the creators as “a breakthrough in at-home oral care.” Globally, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. Options include full-body infrared sauna sessions, which use infrared light to warm the body directly, your body is warmed directly by infrared light. As claimed by enthusiasts, it feels similar to a full-body light therapy session, boosting skin collagen, easing muscle tension, reducing swelling and persistent medical issues and potentially guarding against cognitive decline.

Research and Reservations

“It feels almost magical,” observes Paul Chazot, who has researched light therapy for two decades. Certainly, certain impacts of light on human physiology are proven. Sunlight helps us make vitamin D, needed for bone health, immunity, muscles and more. Light exposure controls our sleep-wake cycles, additionally, triggering the release of neurochemicals and hormones while we are awake, and preparing the body for rest as darkness falls. Sunlight-imitating lamps are standard treatment for winter mood disorders to boost low mood in winter. Clearly, light energy is essential for optimal functioning.

Different Light Modalities

While Sad lamps tend to use a mixture of light frequencies from the blue end of the spectrum, most other light therapy devices deploy red or infrared light. In rigorous scientific studies, such as Chazot’s investigations into the effects of infrared on brain cells, identifying the optimal wavelength is crucial. Light is a form of electromagnetic radiation, spanning from low-energy radio waves to short-wavelength gamma rays. Light-based treatment utilizes intermediate light frequencies, with ultraviolet representing the higher energy invisible light, followed by visible light encompassing rainbow 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 works on the immune system within cells, “and dampens down inflammation,” notes a skin specialist. “Considerable data validates phototherapy.” UVA penetrates skin more deeply than UVB, while the LEDs in consumer devices (typically emitting red, infrared or blue wavelengths) “tend to be a bit more superficial.”

Safety Considerations and Medical Oversight

The side-effects of UVB exposure, like erythema or pigmentation, are recognized but medical equipment uses controlled narrow-band delivery – meaning smaller wavelengths – that reduces potential hazards. “Therapy is overseen by qualified practitioners, meaning intensity is regulated,” explains the dermatologist. Most importantly, 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.”

Consumer Devices and Evidence Gaps

Red and blue light sources, he notes, “don’t have strong medical applications, but could assist with specific concerns.” Red wavelength therapy, proponents claim, enhance blood flow, oxygen uptake and skin cell regeneration, and stimulate collagen production – an important goal for anti-aging. “Studies are available,” states the dermatologist. “Although it’s not strong.” Nevertheless, given the plethora of available tools, “we’re uncertain whether commercial devices replicate research conditions. Appropriate exposure periods aren’t established, ideal distance from skin surface, whether or not that will increase the risk versus the benefit. Numerous concerns persist.”

Targeted Uses and Expert Opinions

One of the earliest blue-light products targeted Cutibacterium acnes, bacteria linked to pimples. Scientific backing remains inadequate for regular prescription – although, explains the specialist, “it’s frequently employed in beauty centers.” Certain patients incorporate it into their regimen, he says, but if they’re buying a device for home use, “we advise cautious experimentation and safety verification. Without proper medical classification, standards are somewhat unclear.”

Cutting-Edge Studies and Biological Processes

Meanwhile, in advanced research areas, scientists have been studying cerebral tissue, revealing various pathways for light-enhanced cell function. “Pretty much everything I did with the light at that particular wavelength was positive and protective,” he says. It is partly these many and varied positive effects on cellular health that have driven skepticism about light therapy – that results appear unrealistic. However, scientific investigation has altered his perspective.

Chazot mostly works on developing drug treatments for neurodegenerative diseases, though twenty years earlier, 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. The specific wavelength measured approximately 1070nm, which most thought had no biological effect.”

Its beneficial characteristic, though, was its ability to transmit through aqueous environments, allowing substantial bodily penetration.

Cellular Energy and Neurological Benefits

More evidence was emerging at the time that infrared light targeted the mitochondria in cells. Mitochondria produce ATP for cell function, producing fuel for biological processes. “All human cells contain mitochondria, including the brain,” explains the neuroscientist, who, as a neuroscientist, decided to focus the research on brain cells. “Research confirms improved brain blood flow with phototherapy, which is generally advantageous.”

With specific frequency application, mitochondria also produce a small amount of a molecule known as reactive oxygen species. At controlled levels these compounds, says Chazot, “stimulates so-called chaperone proteins which look after your mitochondria, preserve cell function and eliminate damaged proteins.”

All of these mechanisms appear promising for treating a brain disease: antioxidant, anti-inflammatory, and cellular cleanup – autophagy being the process the cell uses to clear unwanted damaging proteins.

Present Investigation Status and Expert Assessments

Upon examining current studies on light therapy for dementia, he reports, approximately 400 participants enrolled in multiple trials, comprising his early research projects