LIGHT THERAPY RESEARCH · ALZHEIMER'S DISEASE

What the research says about light therapy and Alzheimer's disease

Photobiomodulation uses specific light wavelengths to support cellular function. It's a big focus in current Alzheimer's research. Here's what the studies are finding.

LIGHT THERAPY RESEARCH · ALZHEIMER'S 

What the research says about light therapy and Alzheimer's disease

Summary of published research – Not medical advice.

THE CONDITION

Understanding Alzheimer's

Alzheimer's is a progressive neurodegenerative disease. It's the most common cause of dementia.

 

It often begins with small signs. You might forget recent conversations. You may struggle to find familiar words. Sometimes, you can get lost in places you know well. Over time, memory loss deepens. Reasoning, judgment, and the ability to do everyday tasks decline.

 

At the cellular level, Alzheimer's is marked by two main proteins: beta-amyloid plaques and tau tangles. Chronic brain inflammation and neuron loss build up in areas linked to memory and learning.

 

The cellular changes begin decades before symptoms show up.

Alzheimer's is a progressive neurodegenerative disease. It's the most common cause of dementia.

 

It often begins with small signs. You might forget recent conversations. You may struggle to find familiar words.

 

Over time, memory loss deepens. Reasoning, judgment, and the ability to do everyday tasks decline.

And researchers are increasingly convinced they don't start in the brain alone.

THE BIOLOGY OF ALZHEIMER'S

Two processes researchers keep coming back to

Mitochondrial dysfunction

Mitochondria are the energy producers inside every cell. In Alzheimer's, they don't make enough ATP — the fuel cells run on. Without enough energy, neurons in memory regions start to falter and die.

 

Pajares et al., 2020

Chronic neuroinflammation

Microglia are the brain's immune cells. In Alzheimer's, microglia get stuck in an active state. They release inflammatory signals that damage neurons. Over years, that chronic inflammation drives the disease forward as much as the protein buildup does.

Heneka et al., 2015

At the cellular level, Alzheimer's is marked by two main proteins: beta-amyloid plaques and tau tangles.

 

Chronic brain inflammation and neuron loss build up in areas linked to memory and learning.

But researchers are increasingly convinced they don't start in the brain alone.

the biology of ALZHEIMER'S

Two processes researchers keep coming back to

Mitochondrial dysfunction

Mitochondria are the energy producers inside every cell. In Alzheimer's, they don't make enough ATP — the fuel cells run on. Without enough energy, neurons in memory regions start to falter and die.

Pajares et al., 2020

Chronic neuroinflammation

Microglia are the brain's immune cells. In Alzheimer's, microglia get stuck in an active state. They release inflammatory signals that damage neurons. Over years, that chronic inflammation drives the disease forward as much as the protein buildup does.

Heneka et al., 2015

LATEST RESEARCH FOCUS

The inflammation loop between gut and brain

Alzheimer's research is shifting. Newer thinking says the disease isn't only about brain plaques. It's also about a cycle of inflammation that starts outside the brain and moves in.

The microbiome looks different

People with Alzheimer's show altered gut microbial diversity compared to healthy controls — a pattern researchers can detect in stool analysis.

Inflammation crosses the barrier

People with Alzheimer's show altered gut microbial diversity compared to healthy controls — a pattern researchers can detect in stool analysis.

The dual-target approach

Recent trials test treatments that target the brain and gut together — based on the idea that addressing only one leaves the inflammation loop intact.

The implication: the inflammation cycle has to be interrupted at both ends. Treating only the brain leaves the source untouched.

Blivet et al., J Integr Neurosci, 2024 · Heneka et al., Lancet Neurology, 2015

HUMAN RCT

Brain-gut PBM in mild-to-moderate Alzheimer's

In a randomized, double-blind, sham-controlled trial with 53 patients, brain-gut PBM was well-tolerated. Compliance was high at 92.5%. Treated patients improved on cognitive tests. This included better ADAS-Cog comprehension scores, longer verbal span, and faster Trail Making Test B results. These improvements remained two months after treatment ended.

Blivet et al., Journal of Alzheimer's Disease, 2022

See the study →

MOUSE MODEL

Neuroprotection in an Alzheimer's mouse model

When brain-gut PBM was used daily on mice with an Alzheimer's-inducing peptide injection, it normalized all altered behaviors and biochemical markers. This suggests the dual approach stopped damage instead of just easing symptoms.

Blivet et al., J Integr Neurosci, 2024

See the study →

INDEPENDENT CONFIRMATION

Gut-targeted PBM matched brain-targeted PBM

In mice with Alzheimer’s, a seperate research group found that PBM targeting the gut improved cognition and pathology. This was similar to the effects of PBM aimed at the brain. Also, it uniquely enhanced the gut microbiome, unlike transcranial PBM.

Microorganisms, 2025

See the study →

IN VITRO RESEARCH · 1070 NM

Symptom improvement in real users

Durham University researchers tracked patients using 1070 nm PBM over three months. Among 23 with neurological and 32 with peripheral symptoms, the group showed statistically significant improvement on patient-reported outcomes. Full report forthcoming.

Zarazua Jimenez & Chazot, Durham University research poster

See the poster →

ON THE HORIZON

ON THE HORIZON

What we're watching in Alzheimer's research

What we're watching in Parkinson's research

01

Larger trials of brain-gut PBM

A pivotal multi-site clinical trial of brain-gut PBM in Alzheimer's patients is currently underway. Larger sample, similar protocol, longer follow-up than the 2022 study.

02

Microbiome-based early detection

If gut changes precede cognitive symptoms, stool analysis could one day help identify people on the path toward Alzheimer's earlier — when intervention is most likely to make a difference.

03

Beyond the amyloid hypothesis

After repeated disappointments with amyloid-targeting drugs, the field is broadening. Inflammation, mitochondrial health, and the gut-brain axis are all being explored as new intervention targets.

ON THE HORIZON

ON THE HORIZON

What we're watching in Parkinson's research

What we're watching in Alzheimer's research

01

Larger trials of brain-gut PBM

A pivotal multi-site clinical trial of brain-gut PBM in Alzheimer's patients is currently underway. Larger sample, similar protocol, longer follow-up than the 2022 study.

02

Microbiome-based early detection

If gut changes precede cognitive symptoms, stool analysis could one day help identify people on the path toward Alzheimer's earlier — when intervention is most likely to make a difference.

03

Beyond the amyloid hypothesis

After repeated failures of amyloid-targeting drugs, the field is exploring inflammation, mitochondrial health, and the gut-brain axis as new targets.

Is PBM Safe + FAQ

Title

What is photobiomodulation?

Photobiomodulation (PBM) uses red and near-infrared light to interact with cells. When red and NIR light hits a cell's mitochondria, it activates an enzyme named cytochrome c oxidase. This helps the cell make more ATP, which is its energy source.

 

PBM is a non-invasive and non-thermal therapy. There’s no heat, no surgery, and no drugs involved. Research has been ongoing for decades, with a focus in the last twenty years on brain health, tissue repair, and inflammation.

Why does my loved one need the gut pad? Their condition is in the brain.

Because newer research suggests Alzheimer's isn't only a brain disease. It's also driven by an inflammation loop that runs between the gut and the brain. Gut imbalance can degrade the intestinal lining, sending inflammatory signals into circulation that eventually activate the brain's immune cells.


Treating only the brain leaves the source of that inflammation untouched. The dual approach is designed to interrupt the loop at both ends.

Does PBM cure Alzheimer's?

No. There is currently no cure for Alzheimer's disease, and PBM is not a treatment or cure.

 

What the research shows so far is that brain-gut PBM has been well-tolerated in trials, and that treated patients in a 2022 randomized study improved on several cognitive measures — improvements that held two months after treatment ended. Larger trials are underway. The science is promising, but still developing.

Is photobiomodulation considered safe in the research?

Over decades of studies, PBM has consistently been marked as low-risk. This holds true when it adheres to established wavelength and dosage parameters. It's non-invasive, non-thermal, and doesn't involve UV or ionizing radiation.

 

The most common side effects in studies are mild. They include occasional headaches, temporary eye fatigue from too much light, or slight skin warmth at higher doses. Serious adverse events are rare in the peer-reviewed literature.

 

Talk to your healthcare provider before starting therapy. This is important, especially if you have any medical conditions. This is especially important for people on photosensitizing medications. It also matters for those with a history of seizures or eye conditions.

References
Blivet, G., et al. (2022). A randomized, double-blind, and sham-controlled trial of an innovative brain-gut photobiomodulation therapy: Safety and patient compliance. Journal of Alzheimer's Disease.
Blivet, G., et al. (2024). Photobiomodulation therapy: A novel therapeutic approach to Alzheimer's disease made possible by the evidence of a brain-gut interconnection. Journal of Integrative Neuroscience.
Blivet, G., et al. (2024). Translation from preclinical research to clinical trials: Brain-gut photobiomodulation therapy for Alzheimer's disease. Journal of Integrative Neuroscience.
Heneka, M. T., et al. (2015). Neuroinflammation in Alzheimer's disease. Lancet Neurology.
Pajares, M., et al. (2020). Inflammation in Parkinson's disease: mechanisms and therapeutic implications. Cells.
Zarazua Jimenez, J. E., & Chazot, P. Photobiomodulation 1070 nm in normal ageing and neurodegenerative diseases. Durham University research poster.