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Phototherapy is clearly enjoying a wave of attention. There are now available light-emitting tools for everything from complexion problems and aging signs to muscle pain and gum disease, the latest being an oral care tool equipped with miniature red light sources, described by its makers as “a major advance in personal mouth health.” Globally, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. There are even infrared saunas available, 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, alleviating inflammatory responses and persistent medical issues and potentially guarding against cognitive decline.

Research and Reservations

“It sounds a bit like witchcraft,” observes Paul Chazot, professor in neuroscience at Durham University and a convert to the value of light therapy. Naturally, we know light influences biological functions. Sunlight enables vitamin D production, needed for bone health, immunity, muscles and more. Natural light synchronizes our biological clocks, as well, activating brain chemicals and hormonal responses in daylight, and preparing the body for rest as darkness falls. Daylight-simulating devices are a common remedy for people with seasonal affective disorder (Sad) to boost low mood in winter. So there’s no doubt we need light energy to function well.

Different Light Modalities

Although mood lamps generally utilize blue-spectrum frequencies, consumer light therapy products mostly feature red and infrared emissions. During advanced medical investigations, including research on infrared’s impact on neural cells, determining the precise frequency is essential. Light is a form of electromagnetic radiation, which runs the spectrum from the lowest-energy, longest wavelengths (radio waves) to high-energy gamma radiation. Therapeutic light application utilizes intermediate light frequencies, with ultraviolet representing the higher energy invisible light, then visible light (all the colours we see in a rainbow) and infrared light visible through night vision technology.

Ultraviolet treatment has been employed by skin specialists for decades to treat chronic skin conditions such as eczema, psoriasis and vitiligo. It affects cellular immune responses, “and dampens down inflammation,” says Dr Bernard Ho. “Considerable data validates phototherapy.” UVA reaches deeper skin layers compared to UVB, whereas the LEDs we see on consumer light-therapy devices (which generally deliver red, infrared or blue light) “typically have shallower penetration.”

Risk Assessment and Professional Supervision

UVB radiation effects, including sunburn or skin darkening, are well known but in medical devices the light is delivered in a “narrow-band” form – signifying focused frequency bands – that reduces potential hazards. “Therapy is overseen by qualified practitioners, thus exposure is controlled,” says Ho. Most importantly, the lightbulbs are calibrated by medical technicians, “to confirm suitable light frequency output – as opposed to commercial tanning facilities, where regulations may be lax, and wavelength accuracy isn’t verified.”

Consumer Devices and Evidence Gaps

Colored light diodes, he says, “aren’t really used in the medical sense, but could assist with specific concerns.” Red wavelength therapy, proponents claim, enhance blood flow, oxygen uptake and dermal rejuvenation, and activate collagen formation – a key aspiration in anti-ageing effects. “Research exists,” comments the expert. “But it’s not conclusive.” In any case, given the plethora of available tools, “it’s unclear if device outputs match study parameters. Appropriate exposure periods aren’t established, how close the lights should be to the skin, whether or not that will increase the risk versus the benefit. Numerous concerns persist.”

Treatment Areas and Specialist Views

Early blue-light applications focused on skin microbes, a microbe associated with acne. Scientific backing remains inadequate for regular prescription – although, notes the dermatologist, “it’s commonly used in cosmetic clinics.” Individuals include it in their skincare practices, he mentions, however for consumer products, “we recommend careful testing and security confirmation. If it’s not medically certified, the regulation is a bit grey.”

Innovative Investigations and Molecular Effects

At the same time, in advanced research areas, Chazot has been experimenting with brain cells, identifying a number of ways in which infrared can boost cellular health. “Pretty much everything I did with the light at that particular wavelength was positive and protective,” he says. The numerous reported benefits have generated doubt regarding phototherapy – that it’s too good to be true. But his research has thoroughly changed his mind in that respect.

The scientist mainly develops medications for neurological conditions, but over 20 years ago, a doctor developing photonic antiviral treatment consulted his scientific background. “He developed equipment for cellular and insect experiments,” he explains. “I remained doubtful. The specific wavelength measured approximately 1070nm, which most thought had no biological effect.”

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

Mitochondrial Effects and Brain Health

Growing data suggested infrared influenced energy-producing organelles. Mitochondria are the powerhouses of cells, creating power for cellular operations. “Mitochondria exist throughout the body, particularly in neural cells,” 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, energy organelles generate minimal reactive oxygen compounds. In limited quantities these molecules, notes the scientist, “activates protective proteins that safeguard mitochondria, protect cellular integrity and manage defective proteins.”

Such mechanisms indicate hope for cognitive disorders: antioxidant, anti-inflammatory, and waste removal – self-digestion mechanisms eliminating harmful elements.

Current Research Status and Professional Opinions

Upon examining current studies on light therapy for dementia, he says, several hundred individuals participated in various investigations, comprising his early research projects