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Phototherapy is certainly having a surge in popularity. You can now buy light-emitting tools designed to address complexion problems and aging signs to sore muscles and periodontal issues, recently introduced is an oral care tool outfitted with miniature red light sources, marketed by the company as “a major advance in at-home oral care.” Internationally, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. There are even infrared saunas available, where instead of hot coals (real or electric) heating the air, the infrared radiation heats your body itself. As claimed by enthusiasts, it’s like bathing in one of those LED-lit beauty masks, stimulating skin elasticity, relaxing muscles, alleviating inflammatory responses and persistent medical issues while protecting against dementia.

Understanding the Evidence

“It feels almost magical,” says Paul Chazot, who has researched light therapy for two decades. Of course, we know light influences biological functions. Sunlight enables vitamin D production, essential for skeletal strength, immune function, and muscular health. Sunlight regulates our circadian rhythms, too, stimulating neurotransmitter and hormone production during daytime, and winding down bodily functions for sleep as it fades into night. Sunlight-imitating lamps are a common remedy for people with seasonal affective disorder (Sad) to elevate spirits during colder months. So there’s no doubt we need light energy to function well.

Different Light Modalities

Although mood lamps generally utilize blue-spectrum frequencies, most other light therapy devices deploy red or infrared light. In rigorous scientific studies, including research on infrared’s impact on neural cells, finding the right frequency is key. Light is a form of electromagnetic radiation, spanning from low-energy radio waves to high-energy gamma radiation. Phototherapy, or light therapy employs mid-spectrum wavelengths, the highest energy of those being invisible ultraviolet, then visible light (all the colours we see in a rainbow) and then infrared (which we can see with night-vision goggles).

UV light has been used by medical dermatologists for many years to treat chronic skin conditions such as eczema, psoriasis and vitiligo. It modulates intracellular immune mechanisms, “and reduces inflammatory processes,” notes a dermatology expert. “Substantial research supports light therapy.” UVA penetrates skin more deeply than UVB, in contrast to LEDs in commercial products (usually producing colored light emissions) “tend to be a bit more superficial.”

Risk Assessment and Professional Supervision

UVB radiation effects, like erythema or pigmentation, are well known but in medical devices the light is delivered in a “narrow-band” form – signifying focused frequency bands – which decreases danger. “Treatment is monitored by medical staff, thus exposure is controlled,” says Ho. Essentially, the devices are tuned by qualified personnel, “to guarantee appropriate wavelength emission – unlike in tanning salons, where it’s a bit unregulated, and we don’t really know what wavelengths are being used.”

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 absorption and dermal rejuvenation, and stimulate collagen production – a key aspiration in anti-ageing effects. “The evidence is there,” comments the expert. “Although it’s not strong.” Regardless, amid the sea of devices now available, “it’s unclear if device outputs match study parameters. Optimal treatment times are unknown, how close the lights should be to the skin, if benefits outweigh potential risks. Many uncertainties remain.”

Targeted Uses and Expert Opinions

Initial blue-light devices addressed acne bacteria, a microbe associated with acne. The evidence for its efficacy isn’t strong enough for it to be routinely prescribed by doctors – despite the fact that, explains the specialist, “it’s often seen in medical spas or aesthetics practices.” Individuals include it in their skincare practices, he observes, however for consumer products, “we advise cautious experimentation and safety verification. Unless it’s a medical device, standards are somewhat unclear.”

Innovative Investigations and Molecular Effects

Meanwhile, in innovative scientific domains, Chazot has been experimenting with brain cells, revealing various pathways for light-enhanced cell function. “Virtually all experiments with specific wavelengths showed beneficial and safeguarding effects,” he states. Multiple claimed advantages have created skepticism toward light treatment – that claims seem exaggerated. But his research has thoroughly changed his mind in that respect.

The researcher primarily focuses on pharmaceutical solutions for brain disorders, but over 20 years ago, a physician creating light-based cold sore therapy requested his biological knowledge. “He developed equipment for cellular and insect experiments,” he explains. “I was pretty sceptical. It was an unusual wavelength of about 1070 nanometres, which most thought had no biological effect.”

The advantage it possessed, however, was its ability to transmit through aqueous environments, enabling deeper tissue penetration.

Mitochondrial Impact and Cognitive Support

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. “All human cells contain mitochondria, including the brain,” says Chazot, who concentrated on cerebral applications. “Research confirms improved brain blood flow with phototherapy, which is generally advantageous.”

Using 1070nm wavelength, mitochondria also produce a small amount of a molecule known as reactive oxygen species. In limited quantities these molecules, notes the scientist, “stimulates so-called chaperone proteins which look after your mitochondria, preserve cell function and eliminate damaged proteins.”

These processes show potential for neurological conditions: antioxidant, inflammation reduction, and pro-autophagy – self-digestion mechanisms eliminating harmful elements.

Present Investigation Status and Expert Assessments

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