Properties and mechanism of action
Insulin is secreted by the pancreas and is a hormone composed of two peptide chains. It regulates the sugar metabolism in the body. The actions of insulin are mediated through the insulin receptors located in the cell membranes of the liver, muscular tissue and fatty tissue.
Insulin increases the production of glycogen (the sugar that will be stored in the body), promotes glucose and amino acids intake into cells, increases fat burning, and accelerates protein synthesis. Thus, insulin is anabolic, a tissue growth-stimulating hormone.
Insulin made by recombinant DNA-technology is used for diabetes treatment by subcutaneous injections. Medical insulins are insulin derivatives that are developed to have an effect either quickly or slowly. By using derivates with varied effect durations and efficacies the sugar balance of diabetics can be regulated individually for each person.
Insulin is also used in connection with the anabolic steroids abuse. The aim is to create anabolic effects but also to decrease the insulin resistance caused by anabolic steroids and growth hormones .
Overdosing of insulin can lead very quickly to hypoglycemia (low blood sugar). Severe hypoglycemia can cause unconsciousness and spasms and can lead to permanent brain injury or death .
The Finnish Antidoping Agency FINADA
 Holt & Sönksen (2008): Growth hormone, IGF-I and insulin and their abuse in sport. British Journal of Pharmacology 154(3): 542–56.
 Auer & Siesjö (1993): Hypoglycaemia: brain neurochemistry and neuropathology. Baillieres Clinical Endocrinology and Metabolism 7(3): 611–25.