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Light therapy is definitely experiencing a moment. You can now buy light-emitting tools for everything from dermatological concerns and fine lines to muscle pain and gum disease, recently introduced is a toothbrush enhanced with tiny red LEDs, marketed by the company as “a significant discovery in at-home oral care.” 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 feels similar to a full-body light therapy session, stimulating skin elasticity, soothing sore muscles, relieving inflammation and long-term ailments while protecting against dementia.

The Science and Skepticism

“It sounds a bit like witchcraft,” notes a neuroscience expert, professor in neuroscience at Durham University and a convert to the value of light therapy. Naturally, we know light influences biological functions. Sunlight helps us make vitamin D, essential for skeletal strength, immune function, and muscular health. Light exposure controls our sleep-wake cycles, as well, triggering the release of neurochemicals and hormones while we are awake, and winding down bodily functions for sleep as it fades into night. Artificial sun lamps are standard treatment for winter mood disorders to boost low mood in winter. Undoubtedly, light plays a vital role in human health.

Various Phototherapy Approaches

Although mood lamps generally utilize blue-spectrum frequencies, the majority of phototherapy tools use red or near-infrared wavelengths. In rigorous scientific studies, such as Chazot’s investigations into the effects of infrared on brain cells, determining the precise frequency is essential. Photons represent electromagnetic waves, extending from long-wavelength radiation to high-energy gamma radiation. Light-based treatment employs mid-spectrum wavelengths, the highest energy of those being invisible ultraviolet, then the visible spectrum we perceive as 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 Dr Bernard Ho. “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) “typically have shallower penetration.”

Safety Protocols and Medical Guidance

The side-effects of UVB exposure, such as burning or tanning, are well known but in medical devices the light is delivered in a “narrow-band” form – signifying focused frequency bands – which minimises the risks. “Therapy is overseen by qualified practitioners, so the dosage is monitored,” explains the dermatologist. And crucially, the devices are tuned by qualified personnel, “to guarantee appropriate wavelength emission – as opposed to commercial tanning facilities, where oversight might be limited, and emission spectra aren’t confirmed.”

Consumer Devices and Evidence Gaps

Red and blue LEDs, he notes, “aren’t really used in the medical sense, but they may help with certain conditions.” Red LEDs, it is proposed, improve circulatory function, oxygen utilization and cell renewal in the skin, and activate collagen formation – a key aspiration in anti-ageing effects. “Studies are available,” comments the expert. “However, it’s limited.” 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. Optimal treatment times are unknown, proper positioning requirements, whether or not that will increase the risk versus the benefit. Many uncertainties remain.”

Targeted Uses and Expert Opinions

Early blue-light applications focused on skin microbes, microorganisms connected to breakouts. Scientific backing remains inadequate for regular prescription – although, explains the specialist, “it’s frequently employed in beauty centers.” Individuals include it in their skincare practices, he says, but if they’re buying a device for home use, “we recommend careful testing and security confirmation. If it’s not medically certified, standards are somewhat unclear.”

Advanced Research and Cellular Mechanisms

At the same time, in advanced research areas, scientists have been studying cerebral tissue, revealing various pathways for light-enhanced cell function. “Virtually all experiments with specific wavelengths showed beneficial and safeguarding effects,” he says. It is partly these many and varied positive effects on cellular health that have driven skepticism about light therapy – that it’s too good to be true. Yet, experimental evidence has transformed his viewpoint.

Chazot mostly works on developing drug treatments for neurodegenerative diseases, however two decades past, a physician creating light-based cold sore therapy requested his biological knowledge. “He designed tools for biological testing,” he explains. “I remained doubtful. It was an unusual wavelength of about 1070 nanometres, that many assumed was biologically inert.”

Its beneficial characteristic, however, was that it travelled through water easily, meaning it could penetrate the body more deeply.

Cellular Energy and Neurological Benefits

Growing data suggested infrared influenced energy-producing organelles. These organelles generate cellular energy, generating energy for them to function. “Every cell in your body has mitochondria, particularly in neural cells,” says Chazot, who concentrated on cerebral applications. “It has been shown that in humans this light therapy increases blood flow into the brain, which is consistently beneficial.”

With specific frequency application, energy organelles generate minimal reactive oxygen compounds. At controlled levels these compounds, notes the scientist, “activates protective proteins that safeguard mitochondria, look after your cells and also deal with the unwanted proteins.”

Such mechanisms indicate hope for cognitive disorders: antioxidant, inflammation reduction, and pro-autophagy – self-digestion mechanisms eliminating harmful elements.

Ongoing Study Progress and Specialist Evaluations

When recently reviewing 1070nm research for cognitive decline, he reports, about 400 people were taking part in four studies, incorporating his preliminary American studies