Many people take glucosamine supplements every day to help support their joints. It has been used for years and is one of the most popular supplements for osteoarthritis. However, a new study is raising questions about whether glucosamine could affect brain health in people with Alzheimer’s disease or mild cognitive impairment.
Researchers found that glucosamine increased a process called hyperglycosylation in Alzheimer’s disease. They also found that glucosamine supplementation worsened memory problems in mice with Alzheimer’s disease, and that people with Alzheimer’s disease or mild cognitive impairment who were taking glucosamine supplements appeared more likely to experience faster disease progression. While these findings are important, they do not prove that glucosamine causes Alzheimer’s disease or speeds it up in people. More research is needed before doctors can change current recommendations.
What Is Glucosamine?
Glucosamine is a naturally occurring compound found in cartilage, the tissue that cushions joints. It is also sold as a dietary supplement and is commonly taken to help relieve joint pain caused by osteoarthritis.
Inside the body, glucosamine is used to build larger sugar molecules called glycans. These glycans attach to proteins in a process known as glycosylation, which helps proteins fold correctly and allows brain cells to communicate with one another.
Normally, glycosylation is an essential process. However, this study found that in Alzheimer’s disease it may become overactive.
What Did the Researchers Discover?
The researchers examined brain tissue from people with Alzheimer’s disease and found much higher levels of hyperglycosylation than in healthy brains.
Hyperglycosylation means proteins have too many sugar molecules attached to them. This abnormal process was especially common in areas of the brain responsible for learning and memory, including the hippocampus and cerebral cortex.
The researchers believe these abnormal sugar changes may interfere with how brain cells function and communicate, contributing to Alzheimer’s disease progression.
How Did Glucosamine Affect Alzheimer’s Disease?
To better understand the role of glucosamine, the researchers studied mice with Alzheimer’s disease.
They found that mice receiving oral glucosamine supplements developed:
- Worse memory and learning problems.
- Higher levels of hyperglycosylation in the brain.
- More changes associated with Alzheimer’s disease.
The researchers also tested the opposite approach. When they reduced glycosylation by blocking key metabolic pathways, memory and learning improved in the Alzheimer’s mouse models.
These findings suggest that excessive glycosylation may play a direct role in Alzheimer’s disease rather than simply occurring alongside it.
What About People Taking Glucosamine?
The researchers also analyzed electronic health records from people with mild cognitive impairment (MCI) and Alzheimer’s disease.
They found that people taking glucosamine supplements were more likely to:
- Progress from mild cognitive impairment to Alzheimer’s disease.
- Have poorer survival after developing Alzheimer’s disease.
However, this part of the research was observational. It found an association, but it cannot prove that glucosamine caused these outcomes. Other health differences between the groups may have influenced the results.
Should You Stop Taking Glucosamine?
Not based on this study alone.
This research raises important questions, but it does not show that glucosamine causes Alzheimer’s disease or that everyone should stop taking the supplement.
If you have Alzheimer’s disease or mild cognitive impairment and regularly take glucosamine, it may be worth discussing this new research with your healthcare provider before making any changes. Larger clinical studies will be needed to determine whether glucosamine truly affects Alzheimer’s disease progression.
What This Means for You
Glucosamine has long been used to support joint health, but this new research suggests scientists should also consider how it may affect the brain.
The study identified hyperglycosylation as a possible new driver of Alzheimer’s disease and found that glucosamine may increase this process. While these findings are promising for future research, they are not enough to change medical advice today. More studies in people will be needed to determine whether glucosamine supplements influence Alzheimer’s disease risk or progression.
Source
- Hawkinson TR, Liu Z, Ribas RA, et al. Hyperglycosylation is a metabolic driver of Alzheimer’s disease. Nat Metab. 2026. Available from: https://www.nature.com/articles/s42255-026-01538-4. Accessed by: https://www.nature.com/articles/s42255-026-01538-4.
