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Light therapy is clearly enjoying a surge in popularity. Consumers can purchase light-emitting tools targeting issues like complexion problems and aging signs to muscle pain and oral inflammation, the latest being a toothbrush enhanced with tiny red LEDs, marketed by the company as “a major advance in at-home oral care.” Worldwide, the market was worth $1bn in 2024 and is projected to grow to $1.8bn by 2035. Options include full-body infrared sauna sessions, which use infrared light to warm the body directly, the infrared radiation heats your body itself. Based on supporter testimonials, it feels similar to a full-body light therapy session, enhancing collagen production, soothing sore muscles, reducing swelling and long-term ailments while protecting against dementia.

Understanding the Evidence

“It feels almost magical,” says Paul Chazot, professor in neuroscience at Durham University and a convert to the value of light therapy. Of course, we know light influences biological functions. Sunlight helps us make vitamin D, crucial for strong bones, immune defense, and tissue repair. Sunlight regulates our circadian rhythms, additionally, activating brain chemicals and hormonal responses in daylight, and winding down bodily functions for sleep as it fades into night. Artificial sun lamps are a common remedy for people with seasonal affective disorder (Sad) to combat seasonal emotional slumps. So there’s no doubt we need light energy to function well.

Types of Light Therapy

While Sad lamps tend to use a mixture of light frequencies from the blue end of the spectrum, the majority of phototherapy tools use red or near-infrared wavelengths. During advanced medical investigations, such as Chazot’s investigations into the effects of infrared on brain cells, determining the precise frequency is essential. Light constitutes electromagnetic energy, spanning from low-energy radio waves to high-energy gamma radiation. Phototherapy, or light therapy employs mid-spectrum wavelengths, with ultraviolet representing the higher energy invisible light, then visible light (all the colours we see in a rainbow) 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 suppresses swelling,” says a dermatology expert. “Considerable data validates phototherapy.” UVA penetrates skin more deeply than UVB, while the LEDs in consumer devices (usually producing colored light emissions) “typically have shallower penetration.”

Safety Protocols and Medical Guidance

The side-effects of UVB exposure, such as burning or tanning, are understood but clinical devices employ restricted wavelength ranges – indicating limited wavelength spectrum – that reduces potential hazards. “Therapy is overseen by qualified practitioners, so the dosage is monitored,” explains the dermatologist. Most importantly, the devices are tuned by qualified personnel, “to confirm suitable light frequency output – different from beauty 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 notes, “aren’t typically employed clinically, but they may help with certain conditions.” Red wavelength therapy, proponents claim, enhance blood flow, oxygen uptake and dermal rejuvenation, and promote collagen synthesis – a primary objective in youth preservation. “Research exists,” states the dermatologist. “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. Optimal treatment times are unknown, proper positioning requirements, if benefits outweigh potential risks. Many uncertainties remain.”

Specific Applications and Professional Perspectives

One of the earliest blue-light products targeted Cutibacterium acnes, a microbe associated with acne. Scientific backing remains inadequate for regular prescription – although, says Ho, “it’s often seen in medical spas or aesthetics practices.” Individuals include it in their skincare practices, he mentions, however for consumer products, “we advise cautious experimentation and safety verification. If it’s not medically certified, the regulation is a bit grey.”

Advanced Research and Cellular Mechanisms

Simultaneously, in advanced research areas, Chazot has been experimenting with brain cells, 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. It is partly these many and varied positive effects on cellular health that have driven skepticism about light therapy – that results appear unrealistic. But his research has thoroughly changed his mind in that respect.

The scientist mainly develops medications for neurological conditions, but over 20 years ago, a physician creating light-based cold sore therapy requested his biological knowledge. “He designed tools for biological testing,” he recalls. “I remained doubtful. It was an unusual wavelength of about 1070 nanometres, that many assumed was biologically inert.”

What it did have going for it, nevertheless, was its efficient water penetration, meaning it could penetrate the body more deeply.

Cellular Energy and Neurological Benefits

Growing data suggested infrared influenced energy-producing organelles. Mitochondria produce ATP for cell function, generating energy for them to function. “Mitochondria exist throughout the body, particularly in neural cells,” notes the researcher, who concentrated on cerebral applications. “Studies demonstrate enhanced cerebral circulation with light treatment, which is consistently beneficial.”

Using 1070nm wavelength, mitochondria also produce a small amount of a molecule known as reactive oxygen species. At controlled levels these compounds, notes the scientist, “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: oxidative protection, swelling control, and waste removal – autophagy being the process the cell uses to clear unwanted damaging proteins.

Ongoing Study Progress and Specialist Evaluations

When recently reviewing 1070nm research for cognitive decline, he reports, several hundred individuals participated in various investigations, comprising his early research projects