A widely used joint supplement, glucosamine, was associated with a 25% higher likelihood that mild cognitive impairment (MCI) would progress to dementia, according to a new study from University of Florida researchers published in Nature Metabolism.
The research
Senior author Ramon Sun, Ph.D., director of the Center for Advanced Spatial Biomolecule Research and associate director for innovation at UF's McKnight Brain Institute, led the work with Yi Guo, Ph.D., and Jiang Bian, Ph.D. The team used artificial intelligence to analyze deidentified UF Health records collected from 2012 to 2024, focusing on patients diagnosed with Alzheimer's disease and related dementias (ADRD) or MCI. Glucosamine use was reported by 8% of patients in both groups — 1,896 people with ADRD and 2,750 people with MCI.
After accounting for age, sex, and demographics, glucosamine use was associated with a 25% higher likelihood that MCI would progress to dementia. Among people who already had ADRD, glucosamine use was also linked to a 25% higher mortality risk during the study period. That mortality association did not appear in the MCI group, which suggests glucosamine may have a stronger effect once dementia is already established.
The researchers also ran laboratory experiments using human brain tissue and mouse models of Alzheimer's disease. Those experiments pointed to a metabolic pathway involving the attachment of sugar structures to proteins — a normal cellular process that appeared excessively active in the Alzheimer's brain, and which glucosamine may intensify.
The findings are preliminary. Observational health-record studies can show associations but cannot prove that glucosamine itself causes dementia to progress; other differences between people who take the supplement and those who do not may contribute to the results. "The electronic health record data are very provocative," said study co-author Matt Gentry, Ph.D., chair of UF's Department of Biochemistry and Molecular Biology. "While it's an association and not proof of causality, it does raise an important clinical question that now deserves much more attention." The team says a human clinical trial is needed to determine whether glucosamine actually causes harm.
Why it matters
About 7 million people in the United States live with Alzheimer's, and millions more have related dementias such as Lewy body or frontotemporal dementia. Many of them take over-the-counter supplements, including glucosamine, which is especially popular among older adults for joint discomfort. This study doesn't tell anyone to stop taking glucosamine, but it does add to a growing body of evidence that disrupted metabolism — how the brain handles sugars, proteins, and energy — may play an important role in neurodegeneration. If you or someone you care for has MCI or early cognitive symptoms, that makes supplement use worth discussing with a clinician rather than assuming it's neutral.
What you can do
- Keep a simple list of every supplement you take, including dose and frequency, and bring it to your next medical appointment.
- If you've been diagnosed with MCI or another cognitive condition, ask your doctor whether glucosamine is appropriate for you given these preliminary findings.
- Don't stop a prescribed or long-used supplement on your own based on a single study — talk it through first.
- Support your cognition with evidence-backed basics: regular physical activity, sleep, blood-pressure control, and social engagement.
Source: ScienceDaily Mind & Brain
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