Can Taking Too Much Glucosamine Cause Dementia? Doctor Urges Some People to Reassess Its Use

A study linking glucosamine with Alzheimer’s disease has worried older people who take the supplement for joint health. But psychiatrist Huang Mao-hsuan of Taipei’s Cardinal Tien Hospital says the findings do not prove that glucosamine causes dementia or makes it worse.

The research, published in April 2026 in Nature Metabolism, found that people with Alzheimer’s may show hyperglycosylation, a process in which some proteins inside cells receive excessive sugar modifications. Researchers said this could affect nerve-cell function. In experiments on mice with Alzheimer’s, glucosamine increased glycosylation in the brain and was followed by poorer memory performance.

The team also examined human medical records and observed less favorable disease-course and survival outcomes among dementia patients who used glucosamine. Huang cautioned that this part of the research relied on retrospective analysis. “The study’s human data mainly used past medical records. It can observe only an association between the two, and cannot fully prove that glucosamine caused dementia to worsen,” he said.

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The study’s human data mainly used past medical records. It can observe only an association between the two, and cannot fully prove that glucosamine caused dementia to worsen.

People who take glucosamine for long periods may already have painful joints, limited mobility, more chronic illnesses or more frequent medical visits. Those factors could themselves be linked to dementia progression or the risk of death, Huang said. Statistical adjustments cannot eliminate every possible confounding factor.

He recommends that people diagnosed with Alzheimer’s disease or dementia, or those experiencing clear cognitive decline, bring their supplements or a photograph of the packaging to a medical appointment. If glucosamine is taken only for joint maintenance and provides no clear benefit, continued use may not be necessary. People with mild cognitive impairment, or those simply worried about future dementia, should not assume the supplement causes dementia. Huang also noted that major groups, including the American College of Rheumatology, the Arthritis Foundation and Britain’s NICE, do not recommend glucosamine as an arthritis treatment. Regular exercise, strength training, weight control, rehabilitation, appropriate pain relief and medical assessment remain the main approaches to managing joint degeneration.

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Health supplements do not mean they are completely risk-free, nor do they mean they are necessarily effective.