September is World Alzheimer’s Month, and 21st September marks World Alzheimer’s Day – a time to talk more openly about dementia awareness, the diseases that cause it, and the research helping us understand how the brain changes over time.
This isn't another “what is the endocannabinoid system?” explainer – we've covered that ground already in our endocannabinoid system guide. Instead, this article takes a closer look at an intriguing question: what does research tell us about the endocannabinoid system (ECS) in the context of Alzheimer’s disease?
You walk into a room and completely forget why you're there. It happens to almost everyone. Usually, the thought comes back and the moment passes.
But as we get older, changes in memory can sometimes prompt a bigger question: what is normal ageing, and when is it worth talking to a doctor?
The brain has a remarkable network of natural regulatory systems that help it respond to changes and maintain balance. One of these is the endocannabinoid system, or ECS. Researchers are increasingly interested in how this system interacts with processes involved in brain health, including communication between nerve cells, immune activity and the body's response to stress.
That makes the ECS an interesting area of research in Alzheimer's disease – not because it is a proven treatment or because CBD has been shown to prevent Alzheimer's, but because understanding the ECS may help researchers better understand how the brain responds to disease.
Around 982,000 people are currently estimated to be living with dementia in the UK, with that number projected to reach 1.4 million by 2040 – and Alzheimer’s disease, the most common cause of dementia, accounts for 2 out of 3 of those cases. Alzheimer’s Society also estimates that 1 in 3 people born today will develop dementia during their lifetime (1,2).
So, what do researchers currently know about the ECS, Alzheimer’s disease and brain health?
A 60-second refresher: what your ECS does on a good day
The endocannabinoid system is a network of receptors, naturally occurring signalling molecules called endocannabinoids, and enzymes involved in making and breaking down those molecules.
Two of the best-known receptors are CB1 and CB2.
CB1 receptors are particularly abundant in the brain and central nervous system, where they are involved in regulating communication between nerve cells and supporting neuroprotection. CB2 receptors are associated more closely with immune function, although they can also be found in the brain, particularly on cells involved in immune signalling.
The body produces its own endocannabinoids, including anandamide and 2-AG. Together, these components form a sophisticated signalling network involved in maintaining physiological balance – a process often described as homeostasis.
The ECS is therefore less like a single switch and more like a network of finely tuned signals responding to what is happening around them.
For a fuller explanation, see our guide to the endocannabinoid system.
What actually happens in an Alzheimer’s brain
Alzheimer’s disease is a complex condition involving multiple processes within the brain. Researchers are still working to understand exactly how these processes interact and which changes happen first.
Three of the best-known features are amyloid plaques, tau pathology and changes in brain immune activity, sometimes described as neuroinflammation or simply brain inflammation.
Sticky roadblocks, known as amyloid plaques, build up between brain cells
Think of how cholesterol can build up inside a blood vessel, gradually narrowing it. Something similar happens in an Alzheimer’s brain.
Amyloid is a protein fragment that can accumulate in the brain and form deposits known as amyloid plaques.
Amyloid is a normal part of brain biology, but in Alzheimer’s disease the balance between production and clearance can change, allowing abnormal accumulation to occur.
These deposits are one of the characteristic features researchers look for when studying Alzheimer’s disease.
Tau tangles disrupt communication inside neurons
Tau is another protein found naturally in nerve cells. One of its normal roles is helping maintain the structure of the cell.
In Alzheimer’s disease, tau can undergo abnormal changes and form aggregates known as neurofibrillary tangles.
These changes are particularly associated with the disruption and eventual loss of nerve cells involved in memory and other cognitive functions.
Chronic neuroinflammation sets in
The brain has its own immune cells, including microglia and astrocytes.
These cells play important roles in maintaining the brain, responding to damage and helping clear cellular debris.
In Alzheimer’s disease, researchers observe changes in the activity of these cells and in the signalling pathways that regulate them – a process known as neuroinflammation, or simply brain inflammation. Understanding these changes is an important area of dementia research (3).
The ECS under pressure: how Alzheimer’s changes the protection system itself
This is where the science becomes particularly interesting.
The ECS doesn't exist separately from the rest of the brain. Its signalling pathways interact with many of the processes researchers are investigating in Alzheimer's disease.
Studies have reported changes in cannabinoid receptors, endocannabinoid levels and the enzymes that regulate endocannabinoid signalling in brains affected by Alzheimer’s disease.
For example, research has investigated:
- CB1 signalling, particularly in regions of the brain involved in learning and memory, and its possible role in neuroprotection.
- CB2 signalling, including its relationship with microglia and other cells involved in immune activity.
- Endocannabinoids such as 2-AG and anandamide, which form part of the body's own signalling network.
- Enzymes such as FAAH and MAGL, which help regulate the levels and activity of endocannabinoids.
Rather than presenting these findings as evidence that the ECS simply “breaks down” in Alzheimer’s, it is more accurate to describe them as evidence of a dynamic change in ECS signalling as the disease develops.
The ECS remains an active area of investigation, and researchers are working to understand what these changes mean and whether particular components of the system could eventually inform neuroprotective measures and become useful targets for new treatments.
At present, however, this remains a research question rather than an established clinical application (4,5).
Why are researchers interested in the ECS?
One reason the ECS has attracted scientific interest is that its signalling pathways intersect with several biological processes relevant to brain function.
Researchers are particularly interested in how cannabinoid receptors and endocannabinoids interact with:
- communication between nerve cells
- immune signalling in the brain
- oxidative and cellular stress
- processes associated with amyloid and tau
- learning and memory pathways
This makes the ECS an intriguing subject for basic neuroscience and Alzheimer's research.
There are also ongoing investigations into whether enzymes involved in endocannabinoid signalling, including FAAH and MAGL, could represent potential future research targets, and whether this understanding could eventually inform neuroprotective measures.
It is important to distinguish this laboratory and early-stage research from established treatments.
There is currently no evidence that CBD supplements prevent, treat or slow the progression of Alzheimer’s disease.
Research into cannabinoids and dementia continues, but findings from laboratory studies, animal research and small clinical studies cannot be used to establish that a CBD food supplement has a therapeutic effect on Alzheimer’s disease (4,5).
Where day-to-day brain health fits in
The ECS is only one part of a much bigger picture when it comes to brain health.
Research into dementia risk shows that many different factors can influence our chances of developing dementia. Some, such as age and genetics, cannot be changed. Others are potentially modifiable.
Alzheimer’s Research UK currently highlights evidence suggesting that up to 45% of dementia cases worldwide are associated with 14 modifiable risk factors. This does not mean that dementia can be prevented simply by making lifestyle changes, but it does reinforce the importance of looking after brain and overall health throughout life (6).
The organisation's practical brain-health advice centres around three broad areas:
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Keep your brain active Learning, reading, hobbies, problem-solving and other mentally stimulating activities can all form part of an active lifestyle. -
Stay connected Maintaining social connections and participating in activities with other people can support overall wellbeing and brain health.
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Look after your heart What is good for cardiovascular health is often good for brain health too. Physical activity, a balanced diet, not smoking and managing conditions such as high blood pressure can all form part of a healthy lifestyle.
There is no single habit that guarantees protection from dementia. The goal is to build healthy habits that support your overall wellbeing across the course of your life (6,7). We’ve covered many of these day-to-day habits that support brain health in our neuroplasticity article, and we’ll be taking a closer look at dementia risk reduction specifically in a future piece.
Where this leaves the ECS conversation
The endocannabinoid system is one of the body's fascinating natural signalling networks, and Alzheimer's research is helping scientists explore just how interconnected its activity is with other aspects of brain biology.
Rather than viewing the ECS as a system that simply “fails” in Alzheimer's, current research paints a more interesting picture: ECS signalling changes as the brain changes, providing researchers with another window into the complex biology of the disease.
That does not mean we can currently use the ECS (or CBD) to prevent or treat Alzheimer's.
It does mean that the ECS remains a worthwhile area of scientific research, and that learning more about how our natural signalling systems work may ultimately contribute to a better understanding of brain health and neurological disease.
And that is exactly why research matters.
If you're worried about memory changes
Part of dementia awareness is knowing when a change is worth raising, not just spotting the statistics. Occasional forgetfulness is common, but persistent or worsening memory problems are worth discussing with a healthcare professional rather than trying to diagnose yourself from an online article.
If you are concerned about your own memory, or someone else's, speak to your GP.
For reliable information about dementia, diagnosis and support, organisations such as Alzheimer's Society and Alzheimer's Research UK are valuable sources of information.
Final thoughts on your brain's protection system and what Alzheimer's reveals about it
The brain is an extraordinarily complex organ, and the endocannabinoid system is just one part of the intricate network that helps regulate its everyday activity.
As researchers continue to investigate Alzheimer's disease, the ECS offers another fascinating piece of the puzzle.
We still have much to learn – but every new insight into how the brain communicates, adapts and responds to change brings us closer to understanding what happens in Alzheimer's disease and, ultimately, how brain health can be better supported.
World Alzheimer’s Day is a timely reminder to keep learning, keep asking questions, and keep supporting the research that is helping us understand the brain.
And if you’d like to support your own ECS as part of your everyday wellness routine, discover supplements for ECS support.
Important information: CBD food supplements are not medicines and are not intended to diagnose, treat, cure or prevent any disease. There are currently no authorised health claims for CBD food products in Great Britain. If you choose to consume a CBD food product, follow the product's directions and current FSA guidance. The FSA currently recommends that healthy adults limit CBD consumption to no more than 10 mg per day. CBD is not recommended for people taking medication unless under medical direction, and it should be avoided during pregnancy, breastfeeding and when trying to conceive. CBD is also not recommended for under-18s or people who are immunosuppressed (8).
Sources
- Alzheimer’s Society (2026a) Facts for the media. https://www.alzheimers.org.uk/what-we-do/news-and-media/facts-media
- Alzheimer’s Society (2026b) Types of dementia: Alzheimer’s disease. https://www.alzheimers.org.uk/about-dementia/types-dementia/alzheimers-disease
- National Institute on Aging (n.d.) What happens to the brain in Alzheimer’s disease? https://www.nia.nih.gov/health/alzheimers-causes-and-risk-factors/what-happens-brain-alzheimers-disease
- International Journal of Molecular Sciences (2024) ‘The endocannabinoid system and Alzheimer’s disease’, International Journal of Molecular Sciences, 25(7), p. 4050. https://www.mdpi.com/1422-0067/25/7/4050
- Frontiers in Psychiatry (2025) [Article on cannabinoids and Alzheimer’s disease/dementia]. Frontiers in Psychiatry. https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2025.1709266/full
- Alzheimer’s Research UK (n.d.) Risk factors for dementia. https://www.alzheimersresearchuk.org/dementia-information/dementia-risk/
- Alzheimer’s Research UK (n.d.) Brain health basics. https://www.alzheimersresearchuk.org/brain-health/brain-health-basics/
- Food Standards Agency (2026) Food Fact Check: CBD safety and health claims. https://food.blog.gov.uk/2026/06/22/food-fact-check-cbd-safety-and-health-claims/
