In general, people with diabetes either have a total lack of insulin (type 1 diabetes) or they have too little insulin or cannot use insulin effectively (type 2 diabetes).
Type 1 diabetes (formerly called juvenile-onset or insulin-dependent diabetes), accounts for 5 to 10 out of 100 people who have diabetes. In type 1 diabetes, the body's immune system destroys the cells that release insulin, eventually eliminating insulin production from the body. Without insulin, cells cannot absorb sugar (glucose), which they need to produce energy.
Type 2 diabetes (formerly called adult-onset or non–insulin-dependent diabetes) can develop at any age. It most commonly becomes apparent during adulthood. But type 2 diabetes in children is rising. Type 2 diabetes accounts for the vast majority of people who have diabetes—90 to 95 out of 100 people. In type 2 diabetes, the body isn't able to use insulin the right way. This is called insulin resistance. As type 2 diabetes gets worse, the pancreas may make less and less insulin. This is called insulin deficiency.