Who should not take glucosamine?

Before taking glucosamine, you should speak with your healthcare provider to determine whether it is safe. Certain medical conditions or medications (including other nutritional or herbal supplements) may put you at higher risk of side effects from glucosamine. Some forms of glucosamine come from shellfish. People with shellfish or iodine allergies should therefore avoid supplements that come from natural sources and instead use only man-made glucosamine. Due to a lack of data in certain populations, glucosamine should not be used in pregnant women, breastfeeding women or children. Glucosamine should likewise not be taken by people with active bleeding or before surgical or dental procedures, as it can increase bleeding risk. If you have asthma, diabetes, a history of bleeding complications, high blood pressure and possibly high cholesterol, you should use glucosamine with caution; it may exacerbate these conditions. Furthermore, if you take certain drugs to alleviate pain, control diabetes, treat cancer or prevent blood clots, speak with your healthcare provider about the potential risks of combining glucosamine with your regular medications.