What are the risks of taking glucosamine?

Glucosamine is a nutritional supplement so its manufacturing process, safety, and potency are not regulated by the U.S. Food and Drug Administration. The purity of this drug is therefore not guaranteed. In fact, there have been reports in which nutritional substances such as glucosamine were made with toxic metals or other substances. In addition, a supplement may have more or less of the active ingredient than what is indicated on the label. It is therefore important to speak with your pharmacist or healthcare provider about safe, reliable sources of glucosamine. You can also look for supplements that follow the rules of Good Manufacturing Practices.

As with any drug, there is a risk of allergic reactions ranging from hives to life-threatening throat swelling when you take glucosamine. Because some forms of glucosamine come from shellfish, people with shellfish or iodine allergies should not take glucosamine unless it is man-made in a laboratory (and therefore does not contain shellfish).

Certain conditions may be exacerbated by glucosamine. People with asthma, diabetes, bleeding conditions, high blood pressure, and possibly high cholesterol should use glucosamine with caution. In addition, glucosamine can interact with prescription or over-the-counter drugs, resulting in a greater risk of medication side effects. You should therefore speak with your healthcare provider about the potential risks of combining glucosamine with your regular medications.

While glucosamine is generally well-tolerated, side effects can occur. These include mild gastrointestinal symptoms; drowsiness; insomnia; headache; skin and nail changes; temporary elevations in heart rate or blood pressure; heart palpitations; an increased risk of cataracts; and possibly liver and kidney damage.