Can Light Therapy Help Memory and Cognitive Decline? What Early Trials in Dementia and MCI Show
This page summarizes published research for general education. It isn't medical advice and doesn't replace guidance from your doctor.
Photobiomodulation — the same mechanism behind red and near-infrared light therapy for pain and skin — has also been tested directly on the brain, aimed at slowing or improving age-related cognitive decline. The idea is that infrared light penetrating the skull can support mitochondrial function in brain cells the way it does in skin and muscle.
What the research looked at
A 2017 case series treated five patients with mild-to-moderately-severe dementia (including possible Alzheimer's disease) using a combination of transcranial and intranasal near-infrared light (810 nm), delivered at home over 12 weeks, targeting brain regions involved in memory.
A more recent 2025 pilot randomized controlled trial tested a similar transcranial photobiomodulation approach in 20 patients with mild cognitive impairment — 10 receiving active treatment, 10 a sham control — using daily home-based sessions and measuring memory, general cognition, and processing speed.
What they found
In the 2017 case series, the dementia patients showed improved scores on cognitive assessments over the treatment period, alongside better sleep and fewer angry outbursts reported by caregivers — though with no control group, some of that could reflect other factors.
The 2025 pilot RCT, which did include a sham control, found the active treatment group had better recognition memory, higher general cognition scores, and faster processing speed than the sham group, with treatment compliance above 98% in both arms.
What this means in practice
This is genuinely early-stage research — a five-person case series and a twenty-person pilot trial are not enough to draw firm conclusions, and neither is a substitute for standard dementia care. What's notable is that a sham-controlled trial replicated the direction of the original case series' findings, which is what justifies the larger trials now underway. If you or a family member is exploring this, treat it as an area to watch and discuss with a neurologist — not yet an established treatment.
Sources
- Significant Improvement in Cognition in Mild to Moderately Severe Dementia Cases Treated with Transcranial Plus Intranasal Photobiomodulation: Case Series Report - Photomedicine and Laser Surgery, 2017
- Transcranial Photobiomodulation (tPBM) for Mild Cognitive Impairment (MCI): Key Findings from a Pilot Randomized Clinical Trial (RCT) - Alzheimer's & Dementia, 2025
Related research
Can Hydrogen Water Help Mild Cognitive Impairment? What a 1-Year Trial Found
A randomized, double-blind, placebo-controlled trial in Current Alzheimer Research found 1 year of hydrogen water did not significantly improve cognitive scores overall, though a small subgroup showed a possible benefit.
1 study cited
Can Light Therapy Help After a Traumatic Brain Injury? What an Early Safety Trial Found
A randomized clinical trial in JAMA Network Open found transcranial light therapy was safe and produced measurable changes in brain imaging after moderate traumatic brain injury — an early but promising signal.
1 study cited
Can Regular Sauna Use Lower Your Risk of Stroke? A 15-Year Finnish Study
A prospective cohort study in Neurology tracking 1,628 adults for nearly 15 years found those who used the sauna 4-7 times a week had a 61% lower risk of stroke than once-a-week users.
1 study cited
