‘It sounds like witchcraft’: can light therapy really give you better skin, cleaner teeth, stronger joints?

Phototherapy is clearly enjoying a surge in popularity. There are now available illuminated devices targeting issues like complexion problems and aging signs as well as sore muscles and oral inflammation, recently introduced is a dental hygiene device equipped with tiny red LEDs, marketed by the company as “a major advance in personal mouth health.” Worldwide, 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, your body is warmed directly by infrared light. According to its devotees, it feels similar to a full-body light therapy session, stimulating skin elasticity, relaxing muscles, reducing swelling and long-term ailments as well as supporting brain health.

The Science and Skepticism

“It appears somewhat mystical,” says a Durham University professor, professor in neuroscience at Durham University and a convert to the value of light therapy. Of course, certain impacts of light on human physiology are proven. Our bodies produce vitamin D through sun exposure, essential for skeletal strength, immune function, and muscular health. Sunlight regulates our circadian rhythms, as well, stimulating neurotransmitter and hormone production during daytime, and preparing the body for rest as darkness falls. Sunlight-imitating lamps are a common remedy for people with seasonal affective disorder (Sad) to combat seasonal emotional slumps. 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, consumer light therapy products mostly feature red and infrared emissions. During advanced medical investigations, like examinations of infrared influence on cerebral tissue, finding the right frequency is key. Photons represent electromagnetic waves, extending from long-wavelength radiation to high-energy gamma radiation. Light-based treatment employs mid-spectrum wavelengths, including invisible ultraviolet radiation, then the visible spectrum we perceive as colors and finally infrared detectable with special equipment.

Dermatologists have utilized UV therapy for extensive periods to manage persistent skin disorders including eczema and psoriasis. It works on the immune system within cells, “and reduces inflammatory processes,” notes a dermatology expert. “Considerable data validates phototherapy.” UVA goes deeper into the skin than UVB, in contrast to LEDs in commercial products (usually producing colored light emissions) “generally affect surface layers.”

Safety Considerations and Medical Oversight

UVB radiation effects, like erythema or pigmentation, are understood but clinical devices employ restricted wavelength ranges – indicating limited wavelength spectrum – which decreases danger. “Treatment is monitored by medical staff, thus exposure is controlled,” says Ho. And crucially, the light sources are adjusted by technical experts, “to guarantee appropriate wavelength emission – unlike in tanning salons, where oversight might be limited, and we don’t really know what wavelengths are being used.”

Commercial Products and Research Limitations

Colored light diodes, he explains, “don’t have strong medical applications, but they may help with certain conditions.” Red wavelength therapy, proponents claim, help boost blood circulation, oxygen uptake and skin cell regeneration, and promote collagen synthesis – an important goal for anti-aging. “Research exists,” comments the expert. “However, it’s limited.” In any case, 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. 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.”

Treatment Areas and Specialist Views

One of the earliest blue-light products targeted Cutibacterium acnes, bacteria linked to pimples. Scientific backing remains inadequate for regular prescription – even though, explains the specialist, “it’s commonly used in cosmetic clinics.” Some of his patients use it as part of their routine, he observes, however for consumer products, “we recommend careful testing and security confirmation. If it’s not medically certified, oversight remains ambiguous.”

Advanced Research and Cellular Mechanisms

Meanwhile, in a far-flung field of pioneering medical science, Chazot has been experimenting with brain cells, 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 reports. The numerous reported benefits have generated doubt regarding phototherapy – 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, however two decades past, a GP who was developing an antiviral light treatment for cold sores sought his expertise as a biologist. “He developed equipment for cellular and insect experiments,” he says. “I was pretty sceptical. The specific wavelength measured approximately 1070nm, that nobody believed did anything biological.”

Its beneficial characteristic, however, was that it travelled through water easily, enabling deeper tissue penetration.

Mitochondrial Effects and Brain Health

More evidence was emerging at the time that infrared light targeted the mitochondria in cells. Mitochondria produce ATP for cell function, generating energy for them to function. “All human cells contain mitochondria, including the brain,” says Chazot, who, as a neuroscientist, decided to focus the research on brain cells. “It has been shown that in humans this light therapy increases blood flow into the brain, which is generally advantageous.”

With specific frequency application, energy organelles generate minimal reactive oxygen compounds. In low doses this substance, 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: free radical neutralization, anti-inflammatory, and cellular cleanup – autophagy being the process the cell uses to clear unwanted damaging proteins.

Current Research Status and Professional Opinions

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