Light therapy, particularly in the form of photobiomodulation (PBM) using near-infrared or red light, shows promising potential as a treatment approach for Alzheimer’s disease (AD), but it remains an emerging and experimental therapy with mixed evidence and ongoing research. It is not yet established as a standard or fully effective treatment, but several studies and trials suggest it may help improve brain function, reduce pathological protein buildup, and alleviate some symptoms associated with AD.
Photobiomodulation involves applying low-power light, often near-infrared light from LEDs or lasers, to the brain either transcranially or through other means. This light is thought to stimulate cellular processes, particularly by increasing the activity of cytochrome c oxidase in mitochondria, which enhances cellular energy production and oxygenation in brain tissue. This mechanism may help the brain repair itself and improve metabolic function, which is often impaired in Alzheimer’s disease[1].
One key rationale for PBM in AD is that it does not target a single pathological mechanism like amyloid-beta plaques or tau tangles but rather supports overall brain health and repair processes. This is important because many drug trials targeting specific AD mechanisms have failed, possibly due to the complexity of the disease and late intervention stages[1].
Animal studies have shown that PBM can inhibit the aggregation of amyloid-beta and improve its clearance, which may slow cognitive decline and memory impairment. PBM may also enhance the glymphatic system, a brain clearance pathway that removes waste products including misfolded proteins implicated in AD. By improving blood flow and cerebrospinal fluid dynamics, PBM could reduce toxic protein buildup and inflammation in the brain[3].
However, results from animal experiments have been inconsistent. Some studies report significant cognitive benefits and reduced pathology, while others find no effect. Large-scale clinical trials in humans are still lacking, so the efficacy and optimal parameters of PBM for AD remain uncertain[3][6].
Recent clinical research efforts include trials by companies like Vielight Inc, which is testing near-infrared light devices designed to stimulate brain repair in AD patients. These trials aim to determine whether PBM can improve cognitive function or slow disease progression in humans[1].
Another innovative approach involves combining light therapy with sound stimulation at specific frequencies (such as 40 Hertz) to activate brain circuits involved in memory and mood regulation. This non-invasive sensory stimulation has shown promise in preclinical studies and is currently being evaluated in clinical trials like the HOPE Study. The goal is to restore brain activity patterns disrupted in AD, potentially improving both cognitive symptoms and associated mood disorders such as anxiety and depression[4][5].
Research from the University of North Carolina has also demonstrated that light-based stimulation can selectively activate brain pathways controlling memory and mood in Alzheimer’s model mice, restoring these functions separately. This suggests that targeted light therapies could be developed to address multiple symptoms of AD beyond memory loss alone[2].
In summary, light therapy for Alzheimer’s disease is a promising but still experimental field. It offers a novel, non-pharmacological approach that may complement existing treatments by enhancing brain metabolism, reducing toxic protein accumulation, and improving neural circuit function. However, more rigorous clinical trials are needed to confirm its effectiveness, determine optimal treatment protocols, and understand long-term benefits and safety.
Sources:
[1] Michael Hamblin, PhD, Psychiatric Times, 2019
[2] UNC School of Medicine, Neuron, 2025
[3] Translational Neurodegeneration, 2025
[4] YouTube interview with Christian Howell, Cognito Therapeutics, 2025
[5] BrightFocus Foundation, 2025
[6] Journal of Alzheimer’s Disease, 2012
