Insulin (IN-suh-lin) is a hormone which helps sugar move out of the bloodstream and into your cells, where it can be burned as fuel. Normally, insulin is produced by the pancreas (PAN-cree-us). But when this process malfunctions, excess sugar remains in the blood, leading to diabetes (die-uh-BEE-tees). In type 1 diabetes, the body makes little or no insulin. In type 2, the body produces adequate insulin, but not in a form that's usable. If you have type 1 diabetes, you'll need daily injections of insulin; if you have type 2, your condition may or may not require these shots. There are five varieties of insulin; each works at a different speed. Some may begin to act in as little as five minutes, while others take up to six hours to start working. The rate is also influenced by your activity level, your individual response, and where you inject the shot. Insulin enters your system fastest when injected near the stomach, and is slowest when injected in the thigh. Shots are usually taken at least twice a day, before meals. Possible side effects of insulin include low blood potassium, allergic reactions, weight gain, and low blood sugar levels. To remain effective, insulin must be stored and taken exactly as directed. For more information, consult a doctor in your area.