‘It seems like sorcery’: is light therapy truly capable of improving your skin, whitening your teeth, and strengthening your joints?

Phototherapy is clearly enjoying a surge in popularity. Consumers can purchase light-emitting tools designed to address complexion problems and aging signs to muscle pain and gum disease, the latest being a dental hygiene device equipped with miniature red light sources, promoted by the creators as “a significant discovery for domestic dental hygiene.” Internationally, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. Options include full-body infrared sauna sessions, where instead of hot coals (real or electric) heating the air, the thermal energy targets your tissues immediately. According to its devotees, it feels similar to a full-body light therapy session, stimulating skin elasticity, relaxing muscles, alleviating inflammatory responses and persistent medical issues as well as supporting brain health.

Research and Reservations

“It feels almost magical,” observes a neuroscience expert, who has researched light therapy for two decades. Of course, certain impacts of light on human physiology are proven. Sunlight helps us make vitamin D, crucial for strong bones, immune defense, and tissue repair. Natural light synchronizes our biological clocks, additionally, activating brain chemicals and hormonal responses in daylight, and signaling the body to slow down for nighttime. Sunlight-imitating lamps are a common remedy for people with seasonal affective disorder (Sad) to elevate spirits during colder months. Clearly, light energy is essential for optimal functioning.

Types of Light Therapy

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. In serious clinical research, like examinations of infrared influence on cerebral tissue, determining the precise frequency is essential. Light is a form of electromagnetic radiation, spanning from low-energy radio waves to short-wavelength gamma rays. Phototherapy, or light therapy utilizes intermediate light frequencies, 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 to treat chronic skin conditions such as eczema, psoriasis and vitiligo. It affects cellular immune responses, “and dampens down inflammation,” says a dermatology expert. “Considerable data validates phototherapy.” UVA penetrates skin more deeply than UVB, whereas the LEDs we see on consumer light-therapy devices (which generally deliver red, infrared or blue light) “generally affect surface layers.”

Safety Protocols and Medical Guidance

The side-effects of UVB exposure, 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, thus exposure is controlled,” says Ho. And crucially, the light sources are adjusted by technical experts, “to guarantee appropriate wavelength emission – different from beauty salons, where oversight might be limited, and emission spectra aren’t confirmed.”

Commercial Products and Research Limitations

Colored light diodes, he says, “aren’t typically employed clinically, though they might benefit some issues.” Red wavelength therapy, proponents claim, improve circulatory function, oxygen absorption and cell renewal in the skin, and promote collagen synthesis – a key aspiration in anti-ageing effects. “Studies are available,” says Ho. “Although it’s not strong.” Nevertheless, given the plethora of available tools, “we’re uncertain whether commercial devices replicate research conditions. Appropriate exposure periods aren’t established, proper positioning requirements, whether or not that will increase the risk versus the benefit. There are lots of questions.”

Targeted Uses and Expert Opinions

One of the earliest blue-light products targeted Cutibacterium acnes, a microbe associated with acne. The evidence for its efficacy isn’t strong enough for it to be routinely prescribed by doctors – although, notes the dermatologist, “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 just tell them to try it carefully and to make sure it has been assessed for safety. Without proper medical classification, oversight remains ambiguous.”

Cutting-Edge Studies and Biological Processes

Simultaneously, in a far-flung field of pioneering medical science, scientists have been studying cerebral tissue, discovering multiple mechanisms for infrared’s cellular benefits. “Pretty much everything I did with the light at that particular wavelength was positive and protective,” he reports. Multiple claimed advantages have created skepticism toward light treatment – that claims seem exaggerated. Yet, experimental evidence has transformed his viewpoint.

The scientist mainly develops medications for neurological conditions, though twenty years earlier, a physician creating light-based cold sore therapy requested his biological knowledge. “He developed equipment for cellular and insect experiments,” he says. “I was quite suspicious. The specific wavelength measured approximately 1070nm, which most thought had no biological effect.”

What it did have going for it, nevertheless, was that it travelled through water easily, allowing substantial bodily penetration.

Mitochondrial Effects and Brain Health

More evidence was emerging at the time that infrared light targeted the mitochondria in cells. These organelles generate cellular energy, producing fuel for biological processes. “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.”

Using 1070nm wavelength, energy organelles generate minimal reactive oxygen compounds. In limited quantities these molecules, says Chazot, “activates protective proteins that safeguard 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 waste removal – autophagy being the process the cell uses to clear unwanted damaging proteins.

Ongoing Study Progress and Specialist Evaluations

Upon examining current studies on light therapy for dementia, he says, approximately 400 participants enrolled in multiple trials, comprising his early research projects