Insulin is a hormone produced in your pancreas by endocrine cells. Without it, cells in your body cannot absorb the glucose they require to produce energy, leading to a condition called diabetes. Because this condition is life threatening, when your pancreas cannot produce insulin or does not produce enough, or when your cells fail to absorb natural insulin, you can get it by injecting manufactured insulin. According to the International Diabetes Federation, a process called recombinant DNA technology now makes manufactured insulin identical to the insulin your pancreas would normally produce.
How Insulin Works
Metabolism changes carbohydrates into simple sugar molecules called glucose, which then pass through the lining of your intestines and enter the blood stream. As this happens, blood sugar levels elevate, causing a normally functioning pancreas to begin secreting the insulin all cells require in order to absorb glucose and convert it to energy. About Sick Kids, a health information site created by Canada's Hospital for Sick Children, notes the amount of insulin secreted directly relates to the amount of blood sugar present, so as cells absorb glucose and blood sugar levels decline, insulin secretion also declines. In addition, your liver also stores a small amount of insulin, called a basal amount, which it secretes between meals and during periods of sleep to ensure brain and nerve cells have a constant supply of energy.
According to the IDF, most people with diabetes use a combination of four types of manufactured insulin that provides the stimulus cells need to absorb blood glucose and regulate blood glucose levels. Each type differs with respect to how quickly it begins working, how quickly it peaks, or reaches its maximum benefit and how long it remains effective.
Rapid Acting
The National Diabetes Information Clearinghouse, a site established by the National Institute of Diabetes and Digestive and Kidney Diseases, describes fast-acting insulin as insulin that begins to take effect within 15 minutes, peaks within 30 to 90 minutes and remains effective for three to five hours. According to Dr. Ian Blumer, author and member of the American Diabetes Association, a rapid-acting insulin, such as aspart, lispro or glulisine is appropriate for taking around mealtime and has an advantage over short-acting insulin in that you do not have to wait as long to begin your meal.
Short Acting
Short-acting insulin, also called Regular Insulin, takes approximately 30 minutes to one hour to begin affecting blood sugar levels, peaks in two to four hours and lasts five to eight hours. According to Dr. John Brill of the University of Wisconsin School of Medicine and Public Health, short-acting insulin is also appropriate to take before a meal, although you must wait longer for it to take effect. Dr. Brill states that in most cases, your doctor will prescribe a combination of a rapid or short-acting insulin you take before meals with a longer acting insulin you take one or two times a day.
Intermediate Acting
An intermediate-acting insulin, also called NPH insulin, helps maintain steady blood sugar levels throughout your day. According to the NDIC, NPH insulin requires one to two injections per day, takes effect within one to three hours, peaks within eight hours and remains effective for 12 to 16 hours.
Long Acting
Long-acting insulin provides the most consistent control over blood sugar levels and provides you the advantage of having to inject it only once per day. Once you inject a long-acting insulin such as detemir or glargine, it takes effect within one hour and remains consistently effective for 24 to 26 hours according to the NCIC.
