Red and near-infrared light therapy is moving from wellness trend to legitimate medical research, with emerging evidence suggesting it may protect brain tissue after injury and slow neurological decline. What started as an unconventional suggestion in a hospital room is now attracting serious scientific attention, with clinical trials exploring whether specific wavelengths of light can preserve neurons and improve outcomes in conditions like Parkinson's disease and stroke recovery.

How Does Light Actually Affect Brain Cells?

The mechanism behind photobiomodulation, the scientific term for using red and near-infrared light to influence cellular processes, centers on mitochondria, the energy-producing structures inside cells. When red or near-infrared wavelengths (roughly 600 to 1,100 nanometers) penetrate tissue, they interact with mitochondria and increase the production of ATP, the molecule that powers cellular functions. This boost in cellular energy may help protect neurons from damage and support tissue repair.

Red light therapy also appears to reduce inflammation and oxidative stress, two processes that contribute to neurological damage. In animal models of Parkinson's disease, photobiomodulation applied to the head preserved dopamine-producing neurons deep in the brain, the cells whose loss drives the disorder's progression. Researchers have observed benefits lasting for weeks after treatment in these models.

What Do Early Human Studies Show About Stroke and Brain Injury?

The most compelling real-world example comes from dermatologist David Ozog at Henry Ford Health in Michigan. In 2021, his 18-year-old son suffered a massive stroke while on vacation in the Bahamas and was airlifted for emergency surgery. While his son lay partially paralyzed in a hospital bed, a colleague at Harvard Medical School called with an unconventional suggestion: red and near-infrared light therapy based on early research with the U.S. Department of Defense.

"Early results hinted that red and near-infrared light applied to the head might protect neural tissue after brain injury," explained the Harvard colleague's research findings to Ozog, who then ordered several panels of light-emitting diodes and began using them on his son in the hospital.

David Ozog, Dermatologist at Henry Ford Health

Today, Ozog's son is walking and back in university. While Ozog cannot definitively prove the light therapy made the difference, he believes it helped. He has since become a strong advocate for the approach, noting that what seemed fringe just a few years ago is now edging toward mainstream medicine.

Which Neurological Conditions Show the Most Promise?

Beyond stroke recovery, researchers are exploring photobiomodulation for several neurological conditions. Clinical trials report improvements in peripheral neuropathy, retinal degeneration, and certain neurological disorders. For some indications, expert groups now recommend red-light regimens as part of standard care.

The most striking early results involve Parkinson's disease. In mouse models, photobiomodulation preserved dopamine-producing neurons and showed benefits lasting weeks after treatment. Early human trials are currently underway using optical fibers that deliver light close to the diseased cells. Unpublished results from researchers at the University of Grenoble Alpes suggest that transcranial light "makes an older brain look more like a younger brain," according to neuroscientist John Mitrofanis.

"The holy grail of neuroscience research is finding an effective neuroprotective treatment that protects the cells from dying," stated John Mitrofanis, a neuroscientist at the University of Grenoble Alpes in France.

John Mitrofanis, Neuroscientist at the University of Grenoble Alpes

What Are the Key Challenges Researchers Still Face?

• Optimal Parameters: Scientists have not yet determined the ideal wavelengths, intensities, treatment timing, delivery methods, and pulse rates for different neurological conditions, making standardized protocols difficult to establish.
• Skull Penetration: Getting enough photons through the human skull to produce meaningful effects on deep brain structures remains a significant technical challenge, with some devices potentially too powerful for over-the-counter use.
• Individual Variation: It remains unclear whether a person's age or skin color should determine the light dose they receive, and whether treatment responses vary across populations.
• Clinical Evidence: While animal models show promise, large-scale human trials are still limited, and more research is needed to confirm benefits and establish safety profiles across different patient groups.

Brian Pryor, chief executive at BWtek Medical, a medical-device company developing transcranial light devices, noted that his team found higher photon doses have greater impacts on the brain. However, devices with such strong outputs "may be too powerful to sell over the counter," he explained.

Why Is This Happening Now?

The timing of this research surge reflects a broader shift in how scientists view light's role in human health. Humans are exposed to less red and near-infrared light than ever before, spending more time indoors away from the sun. Energy-conservation efforts have also narrowed the spectrum of indoor lighting, eliminating many red and near-infrared wavelengths that our bodies evolved to receive.

"We're literally being starved of something that, biologically, we've evolved to receive," said David Ozog, noting the modern reduction in natural red-light exposure.

David Ozog, Dermatologist at Henry Ford Health

The scientific foundation for photobiomodulation is not entirely new. The 1903 Nobel Prize in Physiology or Medicine recognized concentrated light as a treatment for skin tuberculosis. Modern photobiomodulation research emerged in the 1960s after Hungarian scientists accidentally discovered that low-level red light stimulated hair growth in rodents. Interest accelerated in the 1990s when NASA scientists experimenting with red LEDs to grow plants in space noticed that small cuts on their hands healed unusually quickly under the lights.

What's the Current Market and Clinical Status?

Red-light devices are increasingly appearing in dermatology offices, wellness centers, locker rooms, and homes. According to some projections, the global market will surpass $1 billion by 2030, propelled by companies promising benefits for everything from aging skin to attention deficit hyperactivity disorder. However, experts warn that considerable hype surrounds the therapy, and not all at-home devices have been thoroughly, independently tested.

Despite the hype, legitimate clinical progress is being made. In 2025, Ozog joined more than 20 specialists in a major consensus review that concluded the therapy was safe and effective for several types of ulcers, peripheral neuropathy, acute radiation dermatitis, and androgenic alopecia, a type of pattern hair loss. The U.S. Food and Drug Administration approved a red-light device for dry age-related macular degeneration. Since 2020, red-light therapy in the mouth has been included in clinical guidelines for preventing and treating cancer-therapy-related oral mucositis, painful mouth ulcers that can limit treatment and disrupt nutritional intake.

Several transcranial devices are being developed that could offer more practical delivery of photons to treat a variety of psychiatric and neurological diseases. More clinical trials are planned or currently underway, with researchers working to clarify which conditions benefit most and how to optimize treatment protocols for maximum safety and effectiveness.