What is Insulin? Learn About This Essential Hormone

What is insulin? Learn about this essential hormone that regulates blood sugar levels and is vital for managing diabetes.

Insulin is a crucial hormone produced by the pancreas, an organ behind your stomach.1 It comes from a part of the pancreas called the islets of Langerhans. Insulin’s main job is to manage your blood sugar levels. It does this by helping your muscles, liver, and fat cells use glucose for energy. Plus, it stops the body from breaking down proteins and fats.1 Your body carefully controls the amount of insulin it makes. This keeps your blood sugar levels steady.1 Without enough insulin or if your body can’t use it well, you might get diabetes.

Key Takeaways

  • Insulin is a hormone produced by the pancreas that regulates blood sugar levels.
  • Insulin’s main function is to allow cells to take up and use glucose from the bloodstream for energy.
  • Insulin production and release are tightly regulated in healthy individuals.
  • Insulin resistance and inadequate insulin production can lead to conditions like diabetes.
  • Insulin therapy is a critical treatment for individuals with insulin-related disorders.

Introduction to Insulin

Insulin plays a key role in our bodies.2 Its job is crucial; it helps keep our blood sugar in check.2 Without it, cells wouldn’t be able to use sugar effectively. This could lead to high blood sugar and health issues.2

Besides controlling blood sugar, insulin helps store extra sugar as glycogen. This happens in the liver and muscles. Plus, it stops the body from breaking down fat and protein for energy.2

Insulin’s Role in the Body

2 We need insulin to survive.2 It’s important for regulating sugar levels and supporting the body’s functions.2 People who are overweight, obese, or not active might face insulin resistance. This can lead to type 2 diabetes if the pancreas can’t produce enough insulin.2 Thankfully, since the early 20th century, doctors have been able to give us insulin in shot form.2

The Pancreas and Insulin Production

Beta cells in the pancreas make insulin. They’re in a spot called the islets of Langerhans.23 The pancreas, located behind the stomach, also makes other hormones. One of these is glucagon.2 Insulin and glucagon work together to keep our blood sugar just right.2 The beta cells are always watching blood sugar levels. They adjust insulin release to meet the body’s needs.2

What is Insulin?

Insulin’s Function in Regulating Blood Sugar

Insulin helps keep our blood sugar at the right level. It does this by allowing our body’s cells to use glucose for energy.2 Glucose comes from carbs we eat and is released into the blood.

When our blood sugar rises, the pancreas makes and releases insulin. Insulin acts like a key. It opens the cells’ doors to let glucose in. This way, the blood sugar level goes back to normal, keeping us healthy.

The Islets of Langerhans and Beta Cells

Beta cells make insulin. They are found in groups called the islets of Langerhans in the pancreas.3 Within these islets are not just beta cells. There are also alpha cells. Alpha cells make a hormone called glucagon. Glucagon helps when blood sugar gets too low.

The beta cells work hard to watch our blood sugar levels. They release insulin when it is needed. This keeps our blood sugar stable, so we feel good and healthy.

Insulin and blood sugar regulation

How Insulin Works

Insulin’s main job is to help cells take in glucose. It works by attaching to cell surface receptors. Then, it starts a process where glucose transporters move to the cell’s surface.4 This allows glucose to enter cells. If insulin is not there, cells won’t use glucose well, and blood sugar levels can rise.

Insulin’s Effects on Glucose Uptake

Insulin helps cells take in glucose. It does this by binding to its receptors on a cell’s surface. Then, it starts a process that moves glucose transporters, like GLUT4, to the cell’s surface.4 This makes it possible for glucose to enter the cells. Without insulin, cells can’t use glucose well, leading to high blood sugar.

Insulin’s Role in Metabolism

Insulin does more than just control glucose. It’s also important in regulating other metabolic steps. It helps store extra glucose as glycogen in the liver and muscles. Plus, it stops the body from breaking down fat and protein. This keeps the body’s energy use in balance.

Insulin also boosts the making of fatty acids. Plus, it helps save extra calories as fat. This can cause weight gain if there’s too much insulin in the body.4

Regulation of Insulin Release

The pancreas plays a key role in managing insulin release, linking it closely to our blood sugar levels. After you eat, and your blood sugar rises, the pancreas releases more insulin. This hormone helps cells throughout your body use extra glucose. It brings down blood sugar levels to normal. When blood sugar falls, the pancreas makes less insulin. This keeps enough glucose ready for the body’s most important tasks.

Different hormones in our body also affect how much insulin is released. For instance, GLP-1, a gut hormone, helps insulin secretion when we eat. This is called the “incretin effect.” On the other hand, hormones like glucagon and epinephrine can raise your blood sugar. They do this in critical times, like when you’re stressed or have low blood sugar.

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Statistical Data on Insulin Release RegulationSource
Metabolic cycling is crucial for controlling glucose-stimulated insulin secretion.5
Nutrient regulation plays a significant role in insulin secretion and beta-cell functional integrity.5
L-arginine is essential for maintaining pancreatic β-cell functional integrity, metabolism, and defense against inflammatory challenges.5
Amino acid metabolism has implications on insulin secretion and diabetes.5
Sub-chronic activation of glucagon-like peptide-1 (GLP-1) receptors has beneficial effects on glucose homeostasis and insulin secretion in aging mice.5
Conformally coated human and NHP islets exhibited a response to glucose similar to that of naked controls.6
Approximately 80% of secreted insulin gets cleared by the liver before reaching the systemic circulation.6
The glucose dose response curve for insulin secretion by isolated human islets closely mirrors that of humans in vivo.6
Insulin secretion when stimulated by a sudden increase in glucose concentration shows a biphasic response.6
Approximately 90% of insulin secretion is derived from discrete insulin secretory bursts based on 4-minute intervals.6

Hypoglycemia: Too Much Insulin

Hypoglycemia, or low blood sugar, comes from too much insulin. It happens when there’s more insulin than glucose in the body.7 This often occurs with diabetic patients who took excess insulin.7 Sometimes, it’s because of a rare type of tumor that makes too much insulin, an insulinoma.7

Signs of hypoglycemia are shakiness, sweating, faster heart rate, confusion, and in severe cases, seizures or passing out.8 The body fights low blood sugar by releasing glucagon and epinephrine. These hormones help raise blood sugar levels.8

Symptoms of Hypoglycemia

When someone has low blood sugar, they might look pale or feel shaky and sweaty.8 They could also have a headache, feel very hungry, or tired.8

Other symptoms include an irregular heartbeat or being very irritable. Concentrating might be hard too.8 In severe cases, it can lead to being unresponsive or having seizures.8

Treating Hypoglycemia

To treat hypoglycemia, it’s important to quickly raise blood sugar. This can be done by eating or drinking something with fast-acting carbs. For example, glucose tablets, fruit juice, or hard candy.9

If the person can’t swallow, they might need glucagon. It’s a hormone that makes the liver release glucose.8 This can also help quickly increase blood sugar levels. Glucagon is given as a shot.9 Early and fast treatment is key to avoid bad outcomes like coma or death.

Hypoglycemia treatment

Diabetes and Insulin Deficiency

Type 1 diabetes happens when the body’s immune system attacks beta cells in the pancreas. These cells make insulin.10 Since insulin is lacking, blood sugar doesn’t stay in check. This causes symptoms like being very thirsty, going to the bathroom a lot, losing weight, and feeling tired.10 People with type 1 diabetes need to take insulin from outside, using shots or a pump. This helps them stay healthy and avoid serious problems.

Type 2 Diabetes and Insulin Resistance

In type 2 diabetes, the body can’t use the insulin it produces well. This problem is called insulin resistance.10 Things like family history, being overweight, and not being active can lead to this.

At first, the pancreas might make extra insulin to make up for this. But over time, it can’t keep up, leading to high blood sugar.10 To manage type 2 diabetes, changing your lifestyle, taking pills, or sometimes even using insulin can help.

Insulin Therapy

People with diabetes need insulin if their body can’t make enough. They get it through shots with syringes, pens, or pumps. The type of insulin depends on what they need, their lifestyle, and when they take it. Getting the right amount of insulin is key to keeping blood sugar levels in check. It helps avoid diabetes problems in the short and long term.11

Insulin Injections

Insulin pumps are a different way to take insulin. They’re small devices that stick on the body. They give a steady amount of rapid-acting insulin all day. You can also get extra insulin for meals. Insulin pumps might help keep blood sugar stable better than shots. This could lower the chance of low blood sugar in some diabetics.11

Insulin Pumps

Another option is inhaled insulin for diabetes. It’s breathed in, not injected. This can be easier for some people and reduces the need to use needles. Yet, it’s not for everyone because it depends on your lung health and the cost.11

Inhaled Insulin

Rapid-acting insulin starts to work in 15 minutes and lasts up to 4 hours.11 Regular insulin takes about 30 minutes to start working and can last up to 6 hours.11 Intermediate insulin starts working in a few hours, lasts up to 18 hours.11 Long-acting insulin can last for 24 hours or more.11 Breathable insulin starts working quickly, peaks in 30 minutes, and lasts for about 3 hours.11 Insulin can be given with a syringe, pen, pump, or inhaler.11 Your doctor will help decide the best type and amount of insulin for you. They’ll look at your weight, lifestyle, and how your body reacts to insulin. This is very important for people with diabetes, no matter what type they have.11

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The Incretin Effect and GLP-1

The incretin effect happens when the gut senses glucose and tells the body to make more insulin compared to a direct blood injection.12 It works through incretins like GLP-1.12 GLP-1 makes the pancreas release insulin when it detects high blood sugar, keeping things in balance.12 People with type 2 diabetes might not have a strong incretin effect, leading to high blood sugar.13 That’s why medicines like GLP-1 agonists are key in type 2 diabetes care.14

Key Findings on the Incretin Effect and GLP-1
The incretin effect is seen when insulin rises more after eating glucose than after a direct shot of glucose in the blood.14
A study found that some people with a special GIPR gene look thinner and have less body fat.14
The same gene mutation is linked to problems in handling sugar, less GIP in the blood, and a weaker response to GIP in getting insulin out.14
Cats given GLP-1R agonists, which mimic GLP-1, made more insulin as the dose went up after they ate sugar.14
People with type 2 diabetes have less of an incretin effect than those without it.13
In type 2 diabetes, the body reacts a bit more to sugar eaten than to sugar infused, showing a weaker incretin effect.13

These facts give us a deep look at how incretins and GLP-1 work in different situations. They come from scientific studies in medicine and hormones.

Glucagon: The Counterbalance to Insulin

Glucagon is a hormone made by the pancreas’s alpha cells. It operates opposite to insulin. It assists in keeping blood glucose at the right levels.15 Insulin helps cells absorb glucose. Glucagon makes the liver release glucose, which raises blood sugar. This balance is key for healthy blood sugar, making sure cells get enough glucose for energy.

Glucagon’s Role in Regulating Blood Sugar

Glucagon is vital for stable blood sugar. It counters insulin’s effects. Low glucagon can cause low blood sugar, often in infants. Treatment involves glucagon injection.15 Excess glucagon, usually from pancreatic tumors, can cause diabetes or weight loss.15

Hypoglycemia and Glucagon Treatment

Glucagon is critical for severe hypoglycemia. It can save lives. It tells the liver to release stored glucose, raising blood sugar fast. This reverses hypoglycemia symptoms like confusion or seizures.15

Mild hypoglycemia can be managed by eating 15 grams of quick-acting sugars.15 Severe cases require glucagon if symptoms include confusion or seizures with very low blood sugar. There are different types of emergency glucagon. These range from injection kits to nasal sprays.15 Side effects may include nausea or an increased heart rate. After glucagon use, people usually wake up within 15 minutes. They should then see a doctor.15

Conditions Affecting Insulin Production


Insulinoma is a rare tumor that grows in the pancreas’s beta cells.16 These tumors cause the body to make and release too much insulin. This leads to low blood sugar, a condition called hypoglycemia.

People with insulinoma may feel shaky, sweat a lot, and seem confused. In severe cases, they might have seizures or fall into a coma.16

Doctors diagnose insulinoma with blood tests. These tests check insulin and glucose levels. They also use imaging to find the tumor.16

Treating insulinoma often requires surgery to remove the tumor. This surgery helps the body go back to its normal way of managing insulin and blood sugar.

Lifestyle and Insulin Sensitivity

Diet and how active we are key in how well our body uses insulin. Eating lots of refined carbs and sugars might make our bodies less sensitive to insulin. This can mess up our blood sugar.17 Eating whole foods and moving more can improve how our insulin works. Regular exercise, even a little, boosts how well our muscles use glucose. This helps keep our blood sugar under control.18

Diet and Exercise

Too much body weight, especially around the stomach, can make us insulin resistant.17 This leads to releasing stuff that makes our insulin not work right. Not managing blood sugar well can bring on type 2 diabetes and other health problems. Eating right and staying active can better how our bodies handle insulin, cutting these risks.18

Obesity and Insulin Resistance

Working out 30 minutes, 3–5 days a week, can quickly and lastingly improve insulin sensitivity.18 Studies show lift weights help both men and women, with or without diabetes, get more sensitive to insulin.18 Carrying too much weight, especially around the middle, makes insulin work worse and makes diabetes more likely.18 Eating plenty of plants might make our bodies more responsive to insulin.18 Less carbs in our diet and being careful with fructose can boost insulin sensitivity.18 Certain spices and herbs, like fenugreek, turmeric, and ginger, might help how our body uses insulin.18

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Monitoring Insulin Levels

A1C Testing

The A1C test checks long-term blood sugar control in people with diabetes. It shows average glucose levels from the last 2-3 months. This happens because sugar attaches to hemoglobin in red blood cells.19 Doctors use this test to get a clear view of how well blood sugar is managed. This, in turn, helps adjust treatment plans to keep blood sugar in a healthy range.

Glucose Monitoring

Alongside the A1C test, it’s critical for those on insulin to check their blood sugar often. They can do this with a glucose meter, measuring sugar levels throughout the day.20 There are also continuous glucose monitoring (CGM) devices. They offer real-time sugar readings and trends. This info is vital for adjusting insulin doses and lifestyle.20 Regular sugar level checks are important. They prevent problems like low blood sugar and risks linked to high sugar over time.


In conclusion, insulin is a key hormone the pancreas makes. It controls our blood sugar level and many other processes.21 Around the world, 15.5% to 46.5% of adults have insulin resistance. More than 9% have type 2 diabetes, mostly due to this issue.21 Knowing how insulin works, is made, and the problems from not having enough is crucial. It helps manage diabetes and similar conditions well.

To handle diabetes, a mix of lifestyle changes, taking insulin, and checking blood sugar often is important.21 Things like working out, shedding belly fat, eating less sugar, and sleeping better can lower your insulin resistance. Also, eating fewer carbs could make your body react better to insulin. The ketogenic diet, very low in carbs, has shown it could be helpful.21 New findings and treatments in using insulin keep making life better for people with these health issues.

Scientists have learned a lot about how insulin works, thanks to many studies as seen here.22 These findings are the basis for new treatments that help those with insulin problems.23 Making insulin from human genes has greatly changed how we treat diabetes. It’s a more effective and available option for those who need it.


What is insulin?

Insulin is a hormone made by the pancreas. It’s key in managing blood sugar levels and other body processes.

What is the function of insulin?

Its main job is to allow cells to use glucose for energy. It helps keep blood sugar healthy.

How is insulin produced in the body?

Special beta cells in the pancreas make insulin. They watch blood sugar and release insulin to use glucose.

What is the role of insulin in regulating blood sugar?

Insulin tells cells to take in more glucose from the blood. This lowers blood sugar levels to stay healthy.

How does insulin work at the cellular level?

It sticks to cell receptors, starting a chain reaction. This moves glucose into cells for energy.

What other metabolic effects does insulin have?

Besides managing glucose, insulin stores extra glucose as glycogen. It stops fat and protein breakdown and helps make fatty acids.

How is the release of insulin regulated?

The pancreas controls insulin release based on blood sugar. Other hormones like glucagon and GLP-1 also play a part.

What is hypoglycemia, and how is it treated?

Hypoglycemia is low blood sugar from too much insulin and too little glucose. It’s treated by eating fast-acting carbs or, in severe cases, by using glucagon.

How is insulin used to manage diabetes?

People with diabetes get insulin through shots, pens, or pumps if their body can’t make enough. This helps keep blood sugar in check and prevents problems.

What is the incretin effect, and how does it relate to insulin?

When glucose is in the gut, it makes the body respond better to insulin, thanks to hormones like GLP-1. This is the incretin effect.

What is the role of glucagon in relation to insulin?

Glucagon works opposite to insulin, raising blood sugar. It makes the liver release stored glucose when needed.

What is insulinoma, and how does it affect insulin production?

Insulinoma is a tumor of the pancreas that makes too much insulin. This causes low blood sugar spells.

How do lifestyle factors impact insulin sensitivity?

What you eat, how active you are, and your weight affect how well insulin works. Healthy eating, exercise, and a proper weight help your body use insulin better.

How is insulin level monitored in individuals with diabetes?

To check insulin levels, doctors do A1C tests and monitor blood sugar. Patients can do daily checks with meters or continuous glucose monitors.

Source Links

  1. https://www.yourhormones.info/hormones/insulin
  2. https://www.medicalnewstoday.com/articles/323760
  3. https://diabetes.org/health-wellness/medication/insulin-basics
  4. https://www.webmd.com/diabetes/insulin-explained
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3387883/
  6. https://www.sciencedirect.com/topics/medicine-and-dentistry/insulin-release
  7. https://my.clevelandclinic.org/health/diseases/11647-hypoglycemia-low-blood-sugar
  8. https://www.mayoclinic.org/diseases-conditions/hypoglycemia/symptoms-causes/syc-20373685
  9. https://www.webmd.com/diabetes/insulin-overdose
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2613584/
  11. https://medlineplus.gov/ency/patientinstructions/000965.htm
  12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7766765/
  13. https://link.springer.com/article/10.1007/s00125-023-05956-x
  14. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/incretin
  15. https://www.endocrine.org/patient-engagement/endocrine-library/hormones-and-endocrine-function/pancreas-hormones
  16. https://www.news-medical.net/health/Insulin-Diseases.aspx
  17. https://my.clevelandclinic.org/health/diseases/22206-insulin-resistance
  18. https://www.healthline.com/nutrition/improve-insulin-sensitivity
  19. https://www.testing.com/tests/insulin/
  20. https://medlineplus.gov/lab-tests/insulin-in-blood/
  21. https://www.healthline.com/nutrition/insulin-and-insulin-resistance
  22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8232639/
  23. https://www.britannica.com/science/insulin