Even though glucosamine is technically a type of sugar, it doesn't appear to affect blood glucose levels or insulin sensitivity. Some preliminary research had suggested that glucosamine might worsen insulin resistance, which can contribute to increases in blood sugar in people with type 2 diabetes. But subsequent studies refuted these findings.
Glucosamine is one of the most popular dietary supplements sold in the United States, although study results have been mixed regarding its ability to reduce osteoarthritis pain. While glucosamine doesn't appear to affect glucose levels or insulin sensitivity, the supplement can interact with other medications you might be taking — such as warfarin (Coumadin), a blood thinner.