Glucosamine users with mild cognitive impairment progressed to dementia 25% more often

University of Florida researchers reported in June 2026 that people with mild cognitive impairment who took glucosamine progressed to dementia 25% more often than those who did not. The finding, from a Nature Metabolism paper, was published nearly four months ago and resurfaced on aggregator sites on September 27, which is why it is circulating again. It is an association drawn from medical records rather than a trial, and its authors say so themselves. The paper appears in Nature Metabolism, volume 8, issue 6, with Ramon Sun of the University of Florida as senior author and Tara Hawkinson as lead.

Glucosamine is a widely sold over-the-counter joint supplement.

Twelve years of UF Health records

The team analyzed deidentified UF Health records from 2012 to 2024, covering 1,896 people with Alzheimer’s disease and related dementias, known as ADRD, and 2,750 people with mild cognitive impairment. About 8% of each group reported using glucosamine. According to the UF Health release of June 9, glucosamine use was associated with a 25% higher likelihood that mild cognitive impairment progressed to dementia, and with a 25% higher mortality risk among patients who already had ADRD.

The Nature Metabolism abstract describes the retrospective analysis as covering more than 50,000 electronic health records, from which the ADRD and MCI cohorts were drawn. The two numbers describe different groups and different outcomes, and the second should not be read into the first. The ScienceDaily summary from June 10 notes that no mortality increase was seen in the MCI group specifically. The paper’s own abstract, on the Nature Metabolism page, says the same: glucosamine showed no adverse survival effect in mild cognitive impairment, which the authors read as a sign that vulnerability depends on disease stage.

A sugar-tagging pathway that runs hot in the Alzheimer’s brain

The laboratory half of the paper is what gives the records analysis a reason to be taken seriously. Led by Tara Hawkinson and Ramon Sun of the University of Florida’s McKnight Brain Institute, the team used spatial metabolomics on human post-mortem brain tissue and on mouse models, and found elevated N-linked glycans, sugar structures attached to proteins, across affected regions. The abstract attributes this to increased glycan biosynthesis rather than reduced breakdown, and reports the pattern in both an amyloid mouse model and a tau mouse model.

Cutting glycosylation improved memory in the diseased mice without harming healthy ones. Feeding them glucosamine, a sugar-related molecule that crosses the blood-brain barrier and feeds the same pathway, significantly increased the attachment of sugar residues to proteins and worsened memory performance in the Alzheimer’s models. Matt Gentry, a co-author, put the idea plainly: “The Alzheimer’s brain is adding too many of these sugar structures, and this seems to contribute to the disease rather than protect against it.”

Sun, the senior author and director of the Center for Advanced Spatial Biomolecule Research, framed the clinical worry this way: “A lot of these people actively take an over-the-counter supplement that could be making their disease progression worse.”

A researcher quoted by ScienceDaily conceded that “it’s an association and not proof of causality,” but adding that it “does raise an important clinical question” for patients and clinicians weighing a supplement sold without a prescription.

Use in the records was reported rather than measured, and none of the release, the ScienceDaily summaries or the abstract describes how much glucosamine anyone took or for how long. A 25% higher likelihood is also a relative figure: the coverage does not give the absolute share of glucosamine users and non-users who progressed, so the size of the difference in real patients cannot be read from it.

Confounding by joint pain and other objections

The team is explicit that this is not proof, and says a controlled clinical trial in people is needed before anyone recommends stopping the supplement. Records-based studies cannot rule out that the people who take glucosamine differ in other ways, most obviously in having joint pain to treat, and pain, reduced activity and the drugs taken for arthritis could each plausibly track with cognitive decline on their own.

That objection has been made loudly. Daniel Fabricant, president and chief executive of the Natural Products Association, said the electronic-record analysis “does not establish causality” and that the researchers “did not account for hidden variables or confounding factors,” according to NIE Magazine’s June 24 report. Internist Jacob Teitelbaum told the same outlet it is “far more likely that the chronic arthritis pain caused the increased dementia, not the glucosamine,” and pointed to other research, including UK Biobank data, associating glucosamine with lower mortality.

The disagreement is unresolved. The ScienceDaily repost of September 27 adds nothing to the June findings. No randomized trial has since tested it. The 25% figure remains a signal from 2,750 patients at one health system.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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