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Light therapy is definitely experiencing a surge in popularity. Consumers can purchase light-emitting tools for everything from complexion problems and aging signs along with sore muscles and gum disease, the newest innovation is an oral care tool equipped with miniature red light sources, described by its makers as “a breakthrough 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, the thermal energy targets your tissues immediately. According to its devotees, it’s like bathing in one of those LED-lit beauty masks, stimulating skin elasticity, soothing sore muscles, relieving inflammation and chronic health conditions while protecting against dementia.

Understanding the Evidence

“It sounds a bit like witchcraft,” says Paul Chazot, who has researched light therapy for two decades. Naturally, some of light’s effects on our bodies are well established. Sunlight enables vitamin D production, essential for skeletal strength, immune function, and muscular health. Sunlight regulates our circadian rhythms, too, activating brain chemicals and hormonal responses in daylight, and signaling the body to slow down for nighttime. Artificial sun lamps are standard treatment for winter mood disorders to elevate spirits during colder months. Clearly, light energy is essential for optimal functioning.

Different Light Modalities

Although mood lamps generally utilize blue-spectrum frequencies, the majority of phototherapy tools use red or near-infrared wavelengths. In rigorous scientific studies, including research on infrared’s impact on neural cells, finding the right frequency is key. Photons represent electromagnetic waves, which runs the spectrum from the lowest-energy, longest wavelengths (radio waves) to the highest-energy (gamma waves). Phototherapy, or light therapy employs mid-spectrum wavelengths, including invisible ultraviolet radiation, then the visible spectrum we perceive as colors and then infrared (which we can see with night-vision goggles).

Dermatologists have utilized UV therapy for extensive periods to treat chronic skin conditions such as eczema, psoriasis and vitiligo. It works on the immune system within cells, “and dampens down inflammation,” explains Dr Bernard Ho. “Considerable data validates phototherapy.” UVA penetrates skin more deeply than UVB, in contrast to LEDs in commercial products (which generally deliver red, infrared or blue light) “typically have shallower penetration.”

Safety Protocols and Medical Guidance

Potential UVB consequences, including sunburn or skin darkening, are recognized but medical equipment uses controlled narrow-band delivery – meaning smaller wavelengths – which decreases danger. “Treatment is monitored by medical staff, thus exposure is controlled,” says Ho. And crucially, the devices are tuned by qualified personnel, “to guarantee appropriate wavelength emission – different from beauty salons, where regulations may be lax, and we don’t really know what wavelengths are being used.”

Home Devices and Scientific Uncertainty

Red and blue light sources, he explains, “don’t have strong medical applications, but could assist with specific concerns.” Red LEDs, it is proposed, improve circulatory function, oxygen utilization and skin cell regeneration, and activate collagen formation – a primary objective in youth preservation. “Studies are available,” says Ho. “But it’s not conclusive.” Regardless, given the plethora of available tools, “we’re uncertain whether commercial devices replicate research conditions. We don’t know the duration, proper positioning requirements, whether or not that will increase the risk versus the benefit. Many uncertainties remain.”

Treatment Areas and Specialist Views

One of the earliest blue-light products targeted Cutibacterium acnes, microorganisms connected to breakouts. Scientific backing remains inadequate for regular prescription – although, explains the specialist, “it’s frequently employed in beauty centers.” Individuals include it in their skincare practices, he observes, however for consumer products, “we advise cautious experimentation and safety verification. Without proper medical classification, oversight remains ambiguous.”

Advanced Research and Cellular Mechanisms

Meanwhile, in a far-flung field of pioneering medical science, researchers have been testing neural cells, revealing various pathways for light-enhanced cell function. “Virtually all experiments with specific wavelengths showed beneficial and safeguarding effects,” he reports. It is partly these many and varied positive effects on cellular health that have driven skepticism about light therapy – that claims seem exaggerated. Yet, experimental evidence has transformed his viewpoint.

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 created some devices so that we could work with them with cells and with fruit flies,” he explains. “I remained doubtful. The specific wavelength measured approximately 1070nm, which most thought had no biological effect.”

Its beneficial characteristic, nevertheless, was its ability to transmit through aqueous environments, enabling deeper tissue 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, creating power for cellular operations. “Mitochondria exist throughout the body, particularly in neural cells,” says Chazot, who prioritized neurological investigations. “Research confirms improved brain blood flow with phototherapy, which is consistently beneficial.”

With specific frequency application, cellular power plants create limited oxidative molecules. At controlled levels these compounds, notes the scientist, “stimulates so-called chaperone proteins which look after your mitochondria, protect cellular integrity and manage defective proteins.”

All of these mechanisms appear promising for treating a brain disease: free radical neutralization, inflammation reduction, and pro-autophagy – self-digestion mechanisms eliminating harmful elements.

Current Research Status and Professional Opinions

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