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Light-based treatment is certainly having a moment. You can now buy glowing gadgets for everything from dermatological concerns and fine lines as well as aching tissues and periodontal issues, recently introduced is a toothbrush outfitted with miniature red light sources, described by its makers as “a major advance in personal mouth health.” Globally, the sector valued at $1bn last year is expected to increase to $1.8bn within the next decade. Options include full-body infrared sauna sessions, where instead of hot coals (real or electric) heating the air, your body is warmed directly by infrared light. According to its devotees, it’s like bathing in one of those LED-lit beauty masks, stimulating skin elasticity, easing muscle tension, alleviating inflammatory responses and chronic health conditions while protecting against dementia.

Understanding the Evidence

“It sounds a bit like witchcraft,” observes a neuroscience expert, a scientist who has studied phototherapy extensively. Of course, we know light influences biological functions. Our bodies produce vitamin D through sun exposure, crucial for strong bones, immune defense, and tissue repair. Natural light synchronizes our biological clocks, too, activating brain chemicals and hormonal responses in daylight, and winding down bodily functions for sleep as it fades into night. Sunlight-imitating lamps frequently help individuals with seasonal depression to elevate spirits during colder months. So there’s no doubt we need light energy to function well.

Different Light Modalities

Whereas seasonal affective disorder devices typically employ blue-range light, most other light therapy devices deploy red or infrared light. During advanced medical investigations, including research on infrared’s impact on neural cells, finding the right frequency is key. Photons represent electromagnetic waves, which runs the spectrum from the lowest-energy, longest wavelengths (radio waves) to short-wavelength gamma rays. Phototherapy, or light therapy uses wavelengths around the middle of this spectrum, with ultraviolet representing the higher energy invisible light, followed by visible light encompassing rainbow colors and then infrared (which we can see with night-vision goggles).

Ultraviolet treatment has been employed by skin specialists for decades for addressing long-term dermatological issues like vitiligo. It affects cellular immune responses, “and suppresses swelling,” says Dr Bernard Ho. “There’s lots of evidence for phototherapy.” UVA penetrates skin more deeply than UVB, while the LEDs in consumer devices (which generally deliver red, infrared or blue light) “tend to be a bit more superficial.”

Safety Considerations and Medical Oversight

UVB radiation effects, 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 – which minimises the risks. “It’s supervised by a healthcare professional, meaning intensity is regulated,” explains the dermatologist. And crucially, the lightbulbs are calibrated by medical technicians, “to confirm suitable light frequency output – unlike in tanning salons, where oversight might be limited, and emission spectra aren’t confirmed.”

Home Devices and Scientific Uncertainty

Red and blue light sources, he says, “aren’t really used in the medical sense, though they might benefit some issues.” Red light devices, some suggest, help boost blood circulation, oxygen utilization and dermal rejuvenation, and promote collagen synthesis – a key aspiration in anti-ageing effects. “The evidence is there,” comments the expert. “Although it’s not strong.” Nevertheless, given the plethora of available tools, “it’s unclear if device outputs match study parameters. We don’t know the duration, proper positioning requirements, whether or not that will increase the risk versus the benefit. Numerous concerns persist.”

Treatment Areas and Specialist Views

Initial blue-light devices addressed acne bacteria, a microbe associated with acne. Scientific backing remains inadequate for regular prescription – despite the fact that, notes the dermatologist, “it’s often seen in medical spas or aesthetics practices.” 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. Unless it’s a medical device, oversight remains ambiguous.”

Advanced Research and Cellular Mechanisms

At the same time, in innovative scientific domains, 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. Multiple claimed advantages have created skepticism toward light treatment – that results appear unrealistic. However, scientific investigation has altered his perspective.

The researcher primarily focuses on pharmaceutical solutions for brain disorders, but over 20 years ago, a doctor developing photonic antiviral treatment consulted his scientific background. “He created some devices so that we could work with them with cells and with fruit flies,” he says. “I was quite suspicious. The specific wavelength measured approximately 1070nm, that nobody believed did anything biological.”

What it did have going for it, however, was that it travelled through water easily, enabling deeper tissue penetration.

Mitochondrial Effects and Brain Health

Growing data suggested infrared influenced energy-producing organelles. Mitochondria are the powerhouses of cells, producing fuel for biological processes. “All human cells contain mitochondria, particularly in neural cells,” says Chazot, who concentrated on cerebral applications. “Research confirms improved brain blood flow with phototherapy, which is consistently beneficial.”

With 1070 treatment, energy organelles generate minimal reactive oxygen compounds. At controlled levels these compounds, notes the scientist, “triggers guardian proteins that maintain organelle health, preserve cell function and eliminate damaged proteins.”

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

Current Research Status and Professional Opinions

Upon examining current studies on light therapy for dementia, he says, about 400 people were taking part in four studies, comprising his early research projects