But a new study shows... that almost half of those who need the drug, won't have access to it by the year 2030.
As diets and lifestyles change, so do rates of certain diseases and according to the new study these changes will cause a dramatic increase in the number of people living with diabetes.
By the year 2030, 511 million adults around the world, are expected to have Type 2 diabetes and 79 million of those people, will need insulin to manage their condition.
But, researchers say access to insulin will fall well short of demand, if access to drugs remains the same.
They predict only half of those who need insulin will be able to get it.
The authors of the study hope for initiatives to make life-changing insulin available and affordable.