Can Shining Light on Your Head Make You Think Better?
The data strongly suggest yes. This systematic review of 35 human studies found that 83 percent reported positive improvements in cognitive function after transcranial photobiomodulation. All nine studies on participants with cognitive impairment or dementia showed improvements.
Red light therapy, also known as low-level laser therapy (LLLT) or photobiomodulation (PBM), uses specific wavelengths of red and near-infrared light to promote healing and reduce inflammation.
Transcranial photobiomodulation (tPBM) has been studied for over a decade as a possible cognitive intervention. This systematic review pulled together all available human studies to answer a straightforward question: does shining near-infrared light through the skull actually improve how the brain works?
What the Research Shows
The researchers searched PubMed, Scopus, and Web of Science from 1987 to May 2022. They identified 35 studies evaluating tPBM’s effects on learning and memory, attention, executive function, language, and global cognitive function. Of these 35 studies, 29 (82.9 percent) reported positive improvements after tPBM treatment. The results were particularly strong in people with existing cognitive problems. All nine studies that tested tPBM on participants with subjective memory complaints, mild cognitive impairment, or dementia showed cognitive improvements. Healthy adults also showed benefits, though the effects were more variable, suggesting that tPBM may provide the greatest benefit to brains that are underperforming relative to their potential.
Dr. Kumar’s Take
An 83 percent positive rate across 35 human studies is a strong signal. And the fact that every single study in cognitively impaired patients showed improvement tells me that this is not a marginal effect. Brains that are struggling seem to respond especially well to the energy boost that tPBM provides. For healthy adults, the benefits may be more subtle, but they are still measurable. I think about this in terms of brain optimization. If you can safely and painlessly give your brain more energy to work with, why would you not? The evidence supports it, the risks are essentially zero, and the potential upside for an aging population is enormous.
Who Benefits Most
The review reveals an important pattern: the more compromised the brain, the bigger the benefit from tPBM. People with mild cognitive impairment and early dementia showed the most consistent improvements. Healthy young adults showed benefits in specific cognitive tasks but with more variability. This makes biological sense. A brain that is already functioning well has less room for improvement, while a brain struggling with reduced energy production, inflammation, or poor blood flow has the most to gain from the metabolic boost that tPBM provides.
Practical Takeaways
- Transcranial photobiomodulation improved cognitive function in 83 percent of human studies reviewed.
- People with cognitive impairment or early dementia showed the most consistent improvements.
- Healthy adults also showed cognitive benefits, particularly in memory and attention tasks.
- tPBM is a safe, noninvasive intervention with no reported serious adverse effects.
FAQs
What cognitive abilities improved most with tPBM?
The studies reported improvements across multiple cognitive domains including learning, memory, attention, executive function, and global cognitive function. Memory improvements were among the most commonly reported benefits.
How long do the cognitive benefits of tPBM last?
The duration of benefits varied across studies. Some showed improvements lasting days to weeks after a single session, while others showed sustained benefits with ongoing treatment. Regular, consistent use appears to provide the most lasting improvements.
At what age should someone consider tPBM for cognitive health?
The review did not identify a specific age threshold. However, since the greatest benefits were seen in people with some degree of cognitive decline, it may be most valuable for older adults who are noticing changes in their memory or cognitive sharpness. There is no evidence of harm at any age.
Bottom Line
This systematic review of 35 human studies provides strong evidence that transcranial Red light therapy can improve cognitive function, particularly in people with existing cognitive impairment. With an 83 percent positive rate across studies, minimal side effects, and a clear biological mechanism, tPBM deserves serious consideration as a tool for supporting brain health.
