For many older adults, glucosamine is a familiar name. The supplement is widely advertised as a way to support joint health and ease pain from arthritis.
Because it is sold without a prescription and has been used by millions of people for years, many consumers view it as a safe and natural product.
However, new research from the University of Florida suggests that glucosamine may not be harmless for everyone. Scientists have found evidence that people with early memory problems who take glucosamine may be more likely to develop dementia than those who do not use the supplement.
The findings were published in the journal Nature Metabolism.
The researchers emphasize that the study does not prove that glucosamine causes Alzheimer’s disease or other forms of dementia. Instead, it identifies an association that requires further investigation.
Nevertheless, the findings are important because dementia is already a major global health challenge, and glucosamine is one of the most commonly used supplements among older adults.
Alzheimer’s disease is the leading cause of dementia. It gradually destroys memory, thinking skills, and the ability to perform everyday tasks. The disease develops slowly over many years and currently has no cure. In the United States alone, about 7 million people are living with Alzheimer’s disease, and millions of others have related forms of dementia.
Many people first experience a condition called mild cognitive impairment, or MCI. People with MCI have noticeable problems with memory or thinking, but they can still live independently.
Some individuals with MCI remain stable for years, while others eventually develop dementia. Scientists are therefore eager to understand what factors may speed up or slow down this progression.
To explore the possible role of glucosamine, the University of Florida team examined anonymous electronic health records collected between 2012 and 2024.
Using artificial intelligence and advanced data analysis methods, the researchers identified patients who had either dementia or mild cognitive impairment and then looked at their use of glucosamine supplements.
The researchers discovered that glucosamine use was relatively common. Nearly 1,900 people with dementia and more than 2,700 people with mild cognitive impairment reported using the supplement. About eight percent of patients in each group were taking glucosamine.
After taking factors such as age, sex, and demographic differences into account, the researchers made an important observation. People with mild cognitive impairment who used glucosamine were about 25 percent more likely to later develop dementia than people with MCI who did not take the supplement.
The scientists also found another concerning result. Among people who had already been diagnosed with dementia, glucosamine use was associated with a 25 percent higher risk of death. This increase was not seen among people who only had mild cognitive impairment, suggesting that the effects of the supplement may depend on the stage of brain disease.
The team then tried to understand why glucosamine might be linked to worse outcomes.
They focused on a biological process involving proteins and sugar molecules. Proteins are often described as the body’s tiny machines because they perform countless important jobs inside cells. To function properly, many proteins need small sugar molecules attached to them. These sugar tags influence how proteins are folded, transported, and used.
The researchers found evidence that this sugar-tagging system appears to be excessively active in Alzheimer’s disease.
Glucosamine attracted attention because it is a sugar-related molecule that can cross the blood-brain barrier, the protective system that controls what enters the brain. Once glucosamine reaches the brain, it may contribute to the process of attaching sugar molecules to proteins.
To investigate this idea, the scientists conducted experiments in genetically modified mice that had Alzheimer’s-like disease. The researchers found that glucosamine increased the amount of sugar attached to proteins in brain cells. The treated mice also developed worse problems with social memory, including difficulties recognizing and remembering other mice.
Interestingly, when researchers reduced this sugar-tagging activity, memory performance improved.
The team also examined brain tissue donated by people who had Alzheimer’s disease. Compared with healthy brain samples, the Alzheimer’s brains showed much higher levels of sugar attachment to proteins. These findings suggest that this abnormal metabolic process may actively contribute to disease progression.
The researchers believe their work highlights the growing importance of metabolism in neurodegenerative diseases. Traditionally, scientists have focused on amyloid plaques and tau tangles in Alzheimer’s disease. This study suggests that changes in how brain cells process molecules and regulate proteins may also play a major role.
After reviewing the findings, an important message emerges. The study raises questions but does not provide final answers. It cannot prove that glucosamine directly causes dementia or worsens Alzheimer’s disease. Other factors may still influence the results.
However, because glucosamine is used by millions of older adults and because the researchers found biological clues that support the association, the findings deserve careful attention. Larger studies and clinical trials are now needed.
Until more evidence becomes available, people who have mild cognitive impairment or dementia may wish to speak with their doctors before continuing or starting glucosamine supplements.
If you care about Alzheimer’s, please read studies about the likely cause of Alzheimer’s disease , and new non-drug treatment that could help prevent Alzheimer’s.
For more health information, please see recent studies about diet that may help prevent Alzheimer’s, and results showing some dementia cases could be prevented by changing these 12 things.
