Diabetes is a medical condition in which the body does not produce enough of the hormone insulin, or is unable to use the insulin it produces. Insulin is necessary for the body to be able to use glucose (sugar) as a source of energy. When there is not enough insulin, or when the body is unable to use the insulin it produces, the result is a buildup of glucose in the bloodstream, which can lead to a range of symptoms and complications. These include weight loss, increased thirst and urination, fatigue, blurred vision, and eventually, organ damage. Treatments for diabetes include lifestyle changes, medications, and insulin injections.