What is insulin, and how does it work (mechanism of action)?

Insulin is a naturally-occurring hormone secreted by the pancreas. Insulin is required by the cells of the body in order for them to remove and use glucose from the blood. Cells use glucose to produce the energy that they need to carry out their functions. Researchers first gave an active extract of the pancreas containing insulin to a young diabetic patient in 1922, and the FDA first approved insulin in 1939. Currently, insulin used for treatment is derived from beef and pork pancreas as well as recombinant (man-made) technology. The first recombinant human insulin was approved by the FDA in 1982.
People with diabetes mellitus have a reduced ability to take up and use glucose from the blood, and, as a result, the glucose level in the blood rises.
- In type 1 diabetes, the pancreas cannot produce enough insulin. Therefore, insulin therapy is needed.
- In type 2 diabetes, patients produce insulin, but cells throughout the body do not respond normally to insulin. Nevertheless, insulin also may be used in type 2 diabetes to overcome the resistance of the cells to insulin.
By increasing the uptake of glucose by cells and reducing the concentration of glucose in the blood, insulin prevents or reduces the long-term complications of diabetes, including damage to the blood vessels, eyes, kidneys, and nerves. Insulin is administered by injection under the skin (subcutaneously). The subcutaneous tissue of the abdomen is preferred because the absorption of insulin is more consistent from this location than subcutaneous tissues in other locations.
People with diabetes may use different types of insulin to get the optimal effect on their blood sugar levels. Here are 5 types of insulin for diabetes.
- Rapid-acting insulins start working in less than 15 minutes, peak in an hour, and continue working for another two to four hours.
- Regular, also known as short-acting insulin, takes about 30 minutes to reach the bloodstream. Its peak effect is in about two to three hours, and its effect lingers for three to six hours.
- Intermediate-acting insulin reaches the bloodstream in two to four hours, peaks in four to 12 hours, and works for up to 18 hours.
- Long-acting insulin takes six to 10 hours to start working, but it lasts for 20-24 hours.
- Premixed insulins can be a convenient option for some people.
What brand names are available for insulin?
various
Do I need a prescription for insulin?
Yes; No (regular and NPH insulin)
What are the uses of insulin?
Insulin is prescribed for the treatment of type 1 and type 2 diabetes mellitus.
What are common side effects of insulin?
Hypoglycemia is the most common side effect that may occur during insulin therapy. Symptoms of hypoglycemia include:
- Confusion
- Nausea
- Hunger
- Tiredness
- Perspiration
- Headache
- Heart palpitations
- Numbness around the mouth
- Tingling in the fingers
- Tremors
- Muscle weakness
- Blurred vision
- Cold temperature
- Excessive yawning
- Irritability
- Loss of consciousness
Patients may experience blurred vision if they have had elevated blood sugar levels for a prolonged period of time and then have the elevated levels rapidly brought to normal. This is due to a shift of fluid within the lens of the eye. Over time, vision returns to normal. Other side effects that may occur include headaches, skin reactions (redness, swelling, itching, or rash at the site of injection), worsening of diabetic retinopathy, changes in the distribution of body fat (lipodystrophy), allergic reactions, sodium retention, and general body swelling. Insulin causes weight gain and may reduce potassium blood levels. In addition to these side effects, inhaled insulin (Afrezza) may cause throat pain or irritation and cough and patients should inform their healthcare professional of any unresolved symptoms affecting the lungs for follow-up.
SLIDESHOW
Diabetes: What Raises and Lowers Your Blood Sugar Level? See SlideshowWhat is the dosage for insulin?
The abdomen is the preferred site for insulin injection, but the sites of injection must be rotated in order to prevent erosion of the fat beneath the skin, a condition called lipodystrophy.
Dosing is adjusted for each patient. A combination of short-acting/rapid-acting and intermediate insulin or long-acting insulin is typically used.
Is insulin safe to take if I'm pregnant or breastfeeding?
What else should I know about insulin?
How should I keep insulin stored?
- Unopened insulin should be stored between 2 C and 8 C (36 F and 46 F); it should not be placed in a freezer.
- Insulin vials that are being used can be kept at room temperature for up to a month.
- All vials should be protected from sunlight and excessive heat.
- Unused insulin should be thrown away after the expiration date.
- The vials should never be shaken.
Health News
- 5,000+ Measles Cases Threaten Canada’s Elimination Status
- Home Exercises Ease Knee Arthritis Pain
- Puberty: The Signs, Stages & When to See a Doctor
- Medical Debt May Soon Return to Credit Reports
- Sitting For Long Periods? Sip Cocoa Or Munch Berries To Protect Heart Health, Experts Say
More Health News »
Multimedia: Slideshows, Images & Quizzes
-
Type 2 Diabetes: Signs, Symptoms, TreatmentsLearn about type 2 diabetes warning signs, symptoms, diagnosis, and treatment options. Find out why thirst, headaches, and...
-
Type 1 Diabetes (T1D): Symptoms, Causes, Treatments, Vs. Type 2What is type 1 diabetes? There are new treatments for juvenile diabetes, and more people with diabetes can be treated than ever...
-
Diabetes Nerve Pain: Improving Diabetic Peripheral NeuropathyLearn how to cope with the symptoms of diabetic peripheral neuropathy through pain management exercises. Find relief for diabetic...
-
Diabetes: What Raises and Lowers Your Blood Sugar Level?Want to lower your blood sugar? Learn to better control your glucose levels by preventing blood sugar spikes and swings to avoid...
-
Food Cravings Slideshow: Chocolate, Carbs, Salt, SugarLearn which food cravings can wreck your diet. Whether your craving something creamy or crunchy, sweet or salty, food cravings...
-
Salt & Low Sodium Diet QuizDo you love salt? Take the online Salt Quiz to get the facts about dietary salts and sodium in fruits, vegetables, processed...
-
Sugar Quiz: Facts on Diet & SugarSugar lurks in surprising places. Take the Sugar Quiz to learn of the many ways sugar sneaks into your diet and see what you know...
-
Protein Quiz: Foods High in ProteinProtein is a staple in our diets, but what happens if we get too much? Take this quiz to find out the truth about protein and...
-
Type 2 Diabetes: Test Your Medical IQWhat causes type 2 diabetes? Can it be prevented? Take this online quiz and challenge your knowledge of this common condition....
-
Superfoods Quiz: List of Top SuperfoodsTake our Superfoods Quiz! Get to know how unprocessed, raw, organic foods and healthy drinks are rich in nutrients and dietary...
-
Type 1 Diabetes Quiz: Test Your Medical IQWhat are the causes of type 1 diabetes? Take this quiz and challenge your knowledge of causes, symptoms, diagnosis and treatments...
-
Diabetes Quiz: Test Your Medical IQTake the Diabetes Quiz and learn the causes, signs, symptoms, and types of this growing epidemic. What does diabetes have to do...
-
Sugar Addiction Facts: Cravings, Hidden Sugar, and More in PicturesLearn about sugar addiction to see why we often crave sweets and binge on carbs. Learn how sugar affects the brain and get tips...
-
13 Easy Ways to Eat More GreensLearn 13 easy ways to add more greens to your diet. Discover how to add kale, spinach, broccoli rabe and more into your diet.
-
Diabetes Diet: Healthy Meal Plans for Diabetes-Friendly EatingDiscover the best and worst meals for diabetes-savvy dining. See how to avoid carbs and control your blood sugar with healthier...
-
How Diabetes Can Affect Your FeetLearn more about diabetes related foot problems. For people with diabetes, too much glucose in the blood can cause serious foot...
-
12 Reasons to Love the Mediterranean DietThe Mediterranean diet is a delicious way to eat healthy. We show you how to get the most from this diet with foods like olive...
-
Diabetes Travel: Tips for Better Diabetes ControlDiabetes shouldn't stop you from traveling! Learn tips for packing diabetic supplies, controlling blood sugar while changing time...
-
Diabetes: 15 Famous Celebrities With DiabetesSee pictures of celebrities that have been diagnosed with type 1 or type 2 diabetes including Mary Tyler Moore, Salma Hayek, and...
-
Diabetes Diet: 11 Low-Sugar Drink IdeasSearching for low-sugar drink ideas? This pictures slideshow has eleven beverages ideal for people with diabetes and those...
-
Slideshow: Diabetes Management in 10 MinutesLearn 10 simple ways to better manage your diabetes. See tips for controlling blood sugar, diet and exercise and other helpful...
-
10 Muscle-Building Exercises for DiabetesWatch this slideshow on Diabetes and Exercise. If you have diabetes, see how strengthening your muscles with these 10 weight...
Related Disease Conditions
-
Common Medical Abbreviations & TermsDoctors, pharmacists, and other health-care professionals use abbreviations, acronyms, and other terminology for instructions and information in regard to a patient's health condition, prescription drugs they are to take, or medical procedures that have been ordered. There is no approved this list of common medical abbreviations, acronyms, and terminology used by doctors and other health- care professionals. You can use this list of medical abbreviations and acronyms written by our doctors the next time you can't understand what is on your prescription package, blood test results, or medical procedure orders. Examples include: ANED: Alive no evidence of disease. The patient arrived in the ER alive with no evidence of disease. ARF: Acute renal (kidney) failure cap: Capsule. CPAP: Continuous positive airway pressure. A treatment for sleep apnea. DJD: Degenerative joint disease. Another term for osteoarthritis. DM: Diabetes mellitus. Type 1 and type 2 diabetes HA: Headache IBD: Inflammatory bowel disease. A name for two disorders of the gastrointestinal (BI) tract, Crohn's disease and ulcerative colitis JT: Joint N/V: Nausea or vomiting. p.o.: By mouth. From the Latin terminology per os. q.i.d.: Four times daily. As in taking a medicine four times daily. RA: Rheumatoid arthritis SOB: Shortness of breath. T: Temperature. Temperature is recorded as part of the physical examination. It is one of the "vital signs."
-
Type 1 vs. Type 2 Diabetes: Similarities and DifferencesDiabetes is a metabolic disease that involves a problem with the way insulin is processed in the body. People with type 1 diabetes usually are diagnosed during childhood and have a problem with insulin production by the pancreas. On the other hand, type 2 usually is caused by poor diet, lack of exercise and activity, or being overweight. However, there are genetic causes for both of these types of diabetes.
-
Diabetes Mellitus (Type 1 and Type 2)Diabetes is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are referred to as type 1 (insulin dependent) and type 2 (non-insulin dependent). Symptoms of diabetes include increased urine output, thirst, hunger, and fatigue.
-
Rheumatoid Arthritis (RA)Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body.
-
Signs of Diabetes in MenEarly symptoms of diabetes are different in men, such as low testosterone. In many cases, prediabetes that will progress to type 2 diabetes if it is not treated early.
-
Heart AttackA heart attack (myocardial infarction) occurs when the sudden blockage of a coronary artery, usually because of blood clot, causes damage and death to heart muscle. Symptoms of a heart attack may include chest discomfort often described as a pain, pressure or tightness associated with shortness of breath, sweating and nausea.
-
HypoglycemiaLow blood sugar or hypoglycemia occurs when blood sugar is dangerously low and is often complication of type 1 and type 2 diabetes. Learn about symptoms, dangers, and treatment.
-
Type 2 DiabetesType 2 diabetes is a chronic condition that may be reversible with diet and lifestyle changes. Symptoms include excessive thirst, frequent urination, weight loss, fatigue, and an unusual odor to your urine. Most people don't know they have type 2 diabetes until they have a routine blood test. Treatment options include medications, a type 2 diabetes diet, and other lifestyle changes.
-
HyperglycemiaHyperglycemia or high blood sugar is a serious health problem for diabetics. There are two types of hyperglycemia, fasting and postprandial or after-meal hyperglycemia. Hyperglycemia can also lead to ketoacidosis or hyperglycemic hyperosmolar nonketotic syndrome (HHNS). There are a variety of causes of hyperglycemia in people with diabetes. Symptoms of high blood sugar may include increased thirst, headaches, blurred vision, and frequent urination. Treatment can be achieved through lifestyle changes or medication changes. Carefully monitoring blood glucose levels is key to prevention.
-
What Is a High Insulin Level?Insulin is a hormone (a chemical substance that acts as a messenger in the human body) that is secreted by an abdominal organ called the pancreas. High insulin levels are levels of the hormone that are higher than they should be after ingesting glucose.
-
Diabetic KetoacidosisDiabetic ketoacidosis (DKA) is a complication of type 1 diabetes that is life threatening. If a person thinks they may have diabetic ketoacidosis they should seek medical care immediately. Diabetic ketoacidosis happens when a person's insulin levels in the blood become dangerously low. Symptoms of diabetic ketoacidosis include dehydration, abdominal pain, confusion, and nausea and vomiting. Diabetic ketoacidosis needs medical treatment. It cannot be treated at home.
-
Which is Worse - Type 1 or Type 2 Diabetes?Learn about the similarities and differences between Type 1 and Type 2 Diabetes.
-
Diabetes TreatmentThe major goal in treating diabetes is controlling elevated blood sugar without causing abnormally low levels of blood sugar. Type 1 diabetes is treated with insulin, exercise, and a diabetic diet. Type 2 diabetes is first treated with weight reduction, a diabetic diet, and exercise. When these measures fail to control the elevated blood sugar, oral medications are used. If oral medications are still insufficient, insulin medications are considered.
-
Type 2 Diabetes Diet PlanA type 2 diabetes diet or a type 2 diabetic diet is important for blood sugar (glucose) control in people with diabetes to prevent complications of diabetes. There are a variety of type 2 diabetes diet eating plans such as the Mediterranean diet, Paleo diet, ADA Diabetes Diet, and vegetarian diets. Learn about low and high-glycemic index foods, what foods to eat, and what foods to avoid if you have type 2 diabetes.
-
Type 1 DiabetesType 1 diabetes mellitus (juvenile) is an auto-immune disease with no known cause at this time. Symptoms of type 1 diabetes include frequent urination, unintentional weight loss, dry and itchy skin, vision problems, wounds that heal slowly, and excessive thirst. A healthy lifestyle and controlling blood glucose levels can improve life expectancy.
-
Gestational DiabetesLearning how to avoid gestational diabetes is possible and maintaining a healthy weight and diet before and during pregnancy can help. Discover risk factors, tests and treatments for, and signs and symptoms of gestational diabetes.
-
Types of Diabetes Type 2 MedicationsConsumer information about the types of type 2 diabetes medications. Read about the side effects of Precose, Diabinese, Amaryl, Glucophage, Actos, Avandia, Starlix, Prandin, and more. Drug interactions, dosing, storage, and breastfeeding and pregnancy safety information is provided.
-
Eye Problems and DiabetesDiabetes and eye problems are generally caused by high blood sugar levels over an extended period of time. Types of eye problems in a person with diabetes include glaucoma, cataracts, and retinopathy. Examples of symptoms include blurred vision, headaches, eye aches, pain, halos around lights, loss of vision, watering eyes. Treatment for eye problems in people with diabetes depend on the type of eye problem. Prevention of eye problems include reducing blood pressure, cholesterol levels, quitting smoking, and maintaining proper blood glucose levels.
-
Diabetes Foot ProblemsDiabetes-related foot problems can affect your health with two problems: diabetic neuropathy, where diabetes affects the nerves, and peripheral vascular disease, where diabetes affects the flow of blood. Common foot problems for people with diabetes include athlete's foot, fungal infection of nails, calluses, corns, blisters, bunions, dry skin, foot ulcers, hammertoes, ingrown toenails, and plantar warts.
-
Drug AllergyDrug or medication allergies are caused when the immune system mistakenly creates an immune response to a medication. Symptoms of a drug allergic reaction include hives, rash, itchy skin or eyes, dizziness, nausea, diarrhea, fainting, and anxiety. The most common drugs that people are allergic to include penicillins and penicillin type drugs, sulfa drugs, insulin, and iodine. Treatment may involve antihistamines or corticosteroids. An EpiPen may be used for life-threatening anaphylactic symptoms.
-
Diabetic Home Care and MonitoringManaging your diabetes is a full time commitment. The goal of diabetic therapy is to control blood glucose levels and prevent the complications of diabetes. Information about exercise, diet, and medication will help you manage your diabetes better. Blood glucose reagent strips, blood glucose meters, urine glucose tests, tests for urinary ketones, continuous glucose sensors, and Hemoglobin A1C testing information will enable you to mange your diabetes at home successfully.
SLIDESHOW
Diabetes: What Raises and Lowers Your Blood Sugar Level? See SlideshowTreatment & Diagnosis
Medications & Supplements
- Drugs: Questions to Ask Your Doctor or Pharmacist about Your Drugs
- Drug Interactions
- Insulin for Diabetes Treatment (Types, Side Effects, and Preparations)
- How Long Does Insulin Last After Injection?
- What Is Intravenous Insulin Therapy?
- insulin glargine (Lantus)
- insulin NPH
- Amaryl (glimepiride)
- empagliflozin
- Precose (acarbose)
- canagliflozin (Invokana)
- Types of Diabetes Type I And II Medications
- How Do You Give Intravenous Insulin Therapy?
- Bydureon Bcise (exenatide)
- Synjardy XR (empagliflozin and metformin extended-release)
- Xultophy (insulin degludec and liraglutide injection)
Prevention & Wellness
- Once-a-Week Insulin for Type 2 Diabetes Shows Promise in Early Trial
- Price Hikes Have Patients Turning to Craigslist for Insulin, Asthma Inhalers
- Medtronic MiniMed 600 Series Insulin Pumps Recalled
- Medicare Could Save Billions If Allowed to Negotiate Insulin Prices
- Light-Activated Insulin-Producing Cells May Lead to New Drug-Free Diabetes Treatment
Health News
- 5,000+ Measles Cases Threaten Canada’s Elimination Status
- Home Exercises Ease Knee Arthritis Pain
- Puberty: The Signs, Stages & When to See a Doctor
- Medical Debt May Soon Return to Credit Reports
- Sitting For Long Periods? Sip Cocoa Or Munch Berries To Protect Heart Health, Experts Say
More Health News »
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Top insulin Related Articles
Common Medical Abbreviations & TermsDoctors, pharmacists, and other health-care professionals use abbreviations, acronyms, and other terminology for instructions and information in regard to a patient's health condition,...
Diabetes Mellitus (Type 1 and Type 2)Diabetes is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are referred to as type 1 (insulin dependent) and type 2 (non-insulin...
Diabetes QuizTake the Diabetes Quiz and learn the causes, signs, symptoms, and types of this growing epidemic. What does diabetes have to do with obesity and diet? Learn about life as a diabetic.
Signs of Diabetes in MenEarly symptoms of diabetes are different in men, such as low testosterone. In many cases, prediabetes that will progress to type 2 diabetes if it is not treated early.
Exercises for Diabetes Nerve PainLearn how to cope with the symptoms of diabetic peripheral neuropathy through pain management exercises. Find relief for diabetic nerve pain without medication.
Heart AttackA heart attack (myocardial infarction) occurs when the sudden blockage of a coronary artery, usually because of blood clot, causes damage and death to heart muscle. Symptoms of a heart attack may...
HyperglycemiaHyperglycemia or high blood sugar is a serious health problem for diabetics. There are two types of hyperglycemia, fasting and postprandial or after-meal hyperglycemia. Hyperglycemia can also lead to...
HypoglycemiaLow blood sugar or hypoglycemia occurs when blood sugar is dangerously low and is often complication of type 1 and type 2 diabetes. Learn about symptoms, dangers, and treatment.
Insulin Pump for DiabetesAn insulin pump is a wearable device that delivers insulin without the need for repeated needle injections. The insulin pump allows people with diabetes to control blood sugars with technology that...
Protein QuizProtein is a staple in our diets, but what happens if we get too much? Take this quiz to find out the truth about protein and what's behind the high-protein diet craze!
Diabetes: What Raises and Lowers Your Blood Sugar Level?Want to lower your blood sugar? Learn to better control your glucose levels by preventing blood sugar spikes and swings to avoid neuropathy and other diabetes complications. Find foods that lower...
Rheumatoid Arthritis (RA)Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body.
Salt & Low Sodium Diet QuizDo you love salt? Take the online Salt Quiz to get the facts about dietary salts and sodium in fruits, vegetables, processed foods, snacks and soups!
Type 1 DiabetesWhat is type 1 diabetes? There are new treatments for juvenile diabetes, and more people with diabetes can be treated than ever before. Learn the symptoms of T1D, the causes, and find ways to control...
Type 1 vs. Type 2 Diabetes: Similarities and DifferencesDiabetes is a metabolic disease that involves a problem with the way insulin is processed in the body. People with type 1 diabetes usually are diagnosed during childhood and have a problem with...
Type 2 DiabetesType 2 diabetes is a chronic condition that may be reversible with diet and lifestyle changes. Symptoms include excessive thirst, frequent urination, weight loss, fatigue, and an unusual odor to your...
Type 2 Diabetes SignsLearn about type 2 diabetes warning signs, symptoms, diagnosis, and treatment options. Find out why thirst, headaches, and infections could be signs of diabetes. Discover the treatment options for...