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

Light therapy is certainly having a wave of attention. Consumers can purchase light-emitting tools for everything from dermatological concerns and fine lines to sore muscles and oral inflammation, the newest innovation is a toothbrush equipped with tiny red LEDs, marketed by the company as “a significant discovery in personal mouth health.” Globally, the industry reached $1 billion in 2024 and is forecast to expand to $1.8 billion by 2035. Options include full-body infrared sauna sessions, which use infrared light to warm the body directly, the thermal energy targets your tissues immediately. According to its devotees, the experience resembles using an LED facial mask, enhancing collagen production, easing muscle tension, relieving inflammation and long-term ailments while protecting against dementia.

Understanding the Evidence

“It sounds a bit like witchcraft,” says a neuroscience expert, who has researched light therapy for two decades. Certainly, some of light’s effects on our bodies are well established. Our bodies produce vitamin D through sun exposure, needed for bone health, immunity, muscles and more. Light exposure controls our sleep-wake cycles, too, stimulating neurotransmitter and hormone production during daytime, and preparing the body for rest as darkness falls. Daylight-simulating devices frequently help individuals with seasonal depression to boost low mood in winter. Undoubtedly, light plays a vital role in human health.

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 rigorous scientific studies, such as Chazot’s investigations into the effects of infrared on brain cells, identifying the optimal wavelength is crucial. Light is a form of electromagnetic radiation, spanning from low-energy radio waves to the highest-energy (gamma waves). Phototherapy, or light therapy employs mid-spectrum wavelengths, the highest energy of those being invisible ultraviolet, then the visible spectrum we perceive as colors 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 suppresses swelling,” says Dr Bernard Ho. “Considerable data validates phototherapy.” UVA goes deeper into the skin than UVB, whereas the LEDs we see on consumer light-therapy devices (usually producing colored light emissions) “generally affect surface layers.”

Safety Considerations and Medical Oversight

Potential UVB consequences, like erythema or pigmentation, are understood but clinical devices employ restricted wavelength ranges – signifying focused frequency bands – that reduces potential hazards. “Treatment is monitored by medical staff, meaning intensity is regulated,” says Ho. Most importantly, the lightbulbs are calibrated by medical technicians, “to guarantee appropriate wavelength emission – different from beauty salons, where regulations may be lax, and wavelength accuracy isn’t verified.”

Commercial Products and Research Limitations

Red and blue LEDs, he explains, “aren’t typically employed clinically, but they may help with certain conditions.” Red wavelength therapy, proponents claim, help boost blood circulation, oxygen absorption and skin cell regeneration, and promote collagen synthesis – a primary objective in youth preservation. “Studies are available,” comments the expert. “But it’s not conclusive.” In any case, amid the sea of devices now available, “we’re uncertain whether commercial devices replicate research conditions. Optimal treatment times are unknown, proper positioning requirements, the risk-benefit ratio. Numerous concerns persist.”

Targeted Uses and Expert Opinions

Initial blue-light devices addressed acne bacteria, bacteria linked to pimples. 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 advise cautious experimentation and safety verification. Unless it’s a medical device, oversight remains ambiguous.”

Advanced Research and Cellular Mechanisms

At the same time, in advanced research areas, researchers have been testing neural cells, revealing various pathways for light-enhanced cell function. “Nearly every test with precise light frequencies demonstrated advantageous outcomes,” 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.

Chazot mostly works on developing drug treatments for neurodegenerative diseases, though twenty years earlier, a physician creating light-based cold sore therapy requested his biological knowledge. “He designed tools for biological testing,” he says. “I was pretty sceptical. The specific wavelength measured approximately 1070nm, that nobody believed did anything biological.”

What it did have going for it, though, was that it travelled through water easily, allowing substantial bodily 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, producing fuel for biological processes. “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, mitochondria also produce a small amount of a molecule known as reactive oxygen species. In low doses this substance, explains the expert, “triggers guardian proteins that maintain organelle health, protect cellular integrity and manage defective proteins.”

Such mechanisms indicate hope for cognitive disorders: antioxidant, swelling control, and cellular cleanup – autophagy representing cellular waste disposal.

Present Investigation Status and Expert Assessments

Upon examining current studies on light therapy for dementia, he reports, about 400 people were taking part in four studies, including his own initial clinical trials in the US