What are side effects of glucosamine supplements?

There are not enough long-term studies to tell what, if any, side effects glucosamine supplements may have if they are taken for many years. Preliminary results from a recent three-year study did not show more side effects from glucosamine than from a placebo.

Glucosamine does not raise blood sugar. Adverse effects range from minimal to absent. In one large, nonblinded study, about 2% of patients who used glucosamine sulfate stopped participation because of adverse effects. The most frequently mentioned side effects in study participants who take glucosamine sulfate are stomach pain or tenderness, heartburn, diarrhea, and nausea.

At this time, there are no known interactions with other supplements or medications and no conditions that would prohibit taking glucosamine, with the possible exception of diabetes. Animal studies suggest that glucosamine may reduce the efficiency with which insulin removes blood sugar from the bloodstream. There is no evidence that the same effect occurs in humans, and experts do not agree if there is a risk to diabetic patients.

Most side effects of glucosamine are mild and include symptoms like upset stomach, heartburn, indigestion, diarrhea, gas and bloating. If you experience these side effects, try taking glucosamine with food. Glucosamine sulfate sometimes has high levels of sodium or potassium, so read the label if you're on a low-sodium diet or take diuretics, which affect potassium levels.

Glucosamine may cause insulin to work less effectively, so people with diabetes should talk to their doctors and check their blood sugar regularly when taking it. Glucosamine may also raise blood pressure and cholesterol levels.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.