Glucosamine, most commonly used in the form glucosamine sulfate, is a simple molecule derived from glucose, the principal sugar found in blood. In glucosamine, one oxygen atom in glucose is replaced by a nitrogen atom. The chemical term for this modified form of glucose is amino sugar.

Glucosamine is produced naturally in the body, where it is a key building block for making cartilage.

There is no US Dietary Reference Intake for glucosamine. Your body makes all the glucosamine it needs from building blocks found in foods.

Glucosamine is not usually obtained directly from food. Glucosamine supplements are derived from chitin, a substance found in the shells of shrimp, lobsters, and crabs.