There are four main types of insulin: rapid acting insulin, short-acting insulin, intermediate-acting insulin, and long-acting insulin. The rapid acting insulin is used as a bolus dosage . The action onsets in 15 minutes with peak actions in 30 to 90 minutes. Short acting insulin action onsets within 30 minutes with the peak action around 2 to 4 hours. Intermediate acting insulin action onsets within one to two hours with peak action of four to 10 hours. Long-acting insulin is usually given once per day. The action onset is roughly 1 to 2 hours with a sustained action of up to 24 hours. Some insulins are biosynthetic products produced using genetic recombination techniques; formerly, cattle or pig insulins were used, and even sometimes insulin from fish. 
George T Griffing, MD Professor Emeritus of Medicine, St Louis University School of Medicine
George T Griffing, MD is a member of the following medical societies: American Association for the Advancement of Science , International Society for Clinical Densitometry , Southern Society for Clinical Investigation , American College of Medical Practice Executives , American Association for Physician Leadership , American College of Physicians , American Diabetes Association , American Federation for Medical Research , American Heart Association , Central Society for Clinical and Translational Research , Endocrine Society
Disclosure: Nothing to disclose.