What is insulin?

Insulin is a hormone, produced in the pancreas, that regulates many of the body’s metabolic processes that provide cells with energy. The body uses insulin to process glucose, a sugar found in many carbohydrates, for energy. It enables cells in the muscles, fat and liver to absorb glucose from the bloodstream, where it can be used for energy or stored as fat.

Consequently, insulin serves a vital function in managing glucose levels in the blood. The pancreas releases small quantities of insulin when blood glucose levels rise, prompting the cells to absorb more glucose.

The most common medical condition associated with insulin is diabetes mellitus, more commonly known as diabetes…

Quick Stats:

• 1 in 10 Americans (34.2 million people) have diabetes
• More than 88 million Americans have prediabetes
• 90-95% of diabetes cases in the US are type 2 diabetes
• Over 7.4 million Americans use insulin
• $327 billion - est. annual cost of diagnosed diabetes in the US
• Healthcare costs are 2.3 times higher for people with diabetes

What is diabetes?

When you have diabetes, the body either does not produce enough insulin or has problems using the insulin it does produce. There are two main categories of diabetes: type 1 and type 2.

Type 1 diabetes

Type 1 diabetes occurs when the pancreas cannot produce enough insulin to meet the body’s needs. The precise cause has not been found, but type 1 diabetes is often considered to be an autoimmune condition as the immune system attacks and destroys the insulin producing cells.

It is less common than type 2 diabetes, accounting for between 5 and 10 percent of all diabetes cases in the United States, and is often diagnosed in adolescence.

Type 2 diabetes

Type 2 diabetes occurs when the body’s cells develop a resistance to insulin. As this resistance increases, the pancreas creates more insulin to compensate, but eventually there is an increase in blood glucose levels, leading to prediabetes and eventually type 2 diabetes.

Of approximately 34 million Americans with diabetes, around 90 percent have type 2 diabetes. Unlike type 1 diabetes, it most often develops in people over the age of 45 (although it is increasingly common in young adults and children).

What is prediabetes?

Prediabetes is the term for when blood sugar levels are above average, but not sufficiently high enough to be considered type 2 diabetes. If you are diagnosed with prediabetes, lifestyle changes may be effective in reducing blood glucose levels and preventing it from developing into type 2 diabetes.

Physicians may recommend eating a healthier diet, exercising and trying to maintain a healthy weight in order to bring blood glucose levels back within the normal range.

Why is high blood sugar bad?

Over time, high blood glucose, or hyperglycemia, makes it increasingly difficult for the pancreas to make sufficient insulin. As the pancreas keeps trying to produce insulin to keep up with demand, it is eventually damaged permanently.

Another potential complication as a result of high blood sugar is atherosclerosis, or the hardening of blood vessels. This can lead to a host of secondary conditions, including kidney disease, strokes, heart attacks, neuropathy (nerve damage), blindness, and problems with healing wounds.

How do doctors test for diabetes?

There are a number of methods used by physicians to test for diabetes. Most require more than one test to confirm the diagnosis. The main three tests used are the A1C, Fasting Plasma Glucose (FPG) test and the Oral Glucose Tolerance Test (OGTT).

A1C Test

This measures your average blood sugar over the last 2-3 months and does not require fasting.

• Normal - under 5.7%
• Prediabetes - 5.7% to 6.4%
• Diabetes - 6.5% or higer

Fasting Plasma Glucose (FPG)

The FPG test monitors the body’s fasting blood sugar levels. Patients fast and do not drink anything except water for at least eight hours before the test is administered. It is usually conducted in the morning before breakfast.

• Normal - less than 100 mg/dl
• Prediabetes - between100 mg/dl and 125 mg/dl
• Diabetes - 126 mg/dl or higher

Oral Glucose Tolerance Test (OGTT)

This test takes two hours and provides data on how the body processes sugar. Blood sugar levels are tested before the patient is given a sweet drink, then two hours after

• Normal -under 140 mg/dl
• Prediabetes -140 mg/dl to 199 mg/dl
• Diabetes - 200 mg/dl or higher

How is insulin used to treat diabetes?

Insulin comes either dissolved or suspended in a liquid. The most common strength found in the United States is U-100, but stronger U-500 insulin is also available for people with a particularly high insulin resistance. This number indicates the number of units of insulin per milliliter of liquid, for example, U-100 contains 100 units of insulin per milliliter. Most people with type 1 diabetes, and around 40% of those with type 2 diabetes, require insulin injections to manage their blood glucose levels. The types of insulin can be differentiated by three main characteristics:

• Onset - or the length of time it takes for the insulin torch the bloodstream and start working on lowering blood sugar levels.
• Peak time - or the time at which the insulin is at its most effective.
• Duration - or the length of time the insulin continues to lower the blood glucose levels.

Types of Insulin

Rapid-acting insulin

Rapid-acting insulins, such as Novolog (aspart) or Humalog (lispro), start working around 15 minutes after it is injected. They are the most similar to the insulin produced naturally in the body and work for a short amount of time, peaking at between 1-2 hours and lasting for 2-4 hours. Rapid-acting insulins are commonly administered at the start of a meal.

Regular or short-acting insulin

Short-acting insulins, such as Humulin R (lispro) or Novolin R (regular insulin), start working after around 30 minutes, peak at 3 hours and usually last for 3-6 hours. It is often taken half an hour before a meal.

Intermediate-acting insulin

Intermediate-acting insulins, such as Humulin N (isophane) and Novolin N (isophane), take 1-1.5 hours to work, typically peak at between four and 12 hours and last for around 14 hours. They often look slightly cloudy due to the addition of substances to make them work over longer periods of time.

Long-acting insulin

Unlike other insulins, long-acting insulins, for example Lantus (glargine) or Levemir (determir), do not have a peak. They usually take between three and four hours to get to work and last for up to 24 hours.

Ultra long-acting insulin

Ultra long-acting insulins, such as Toujeo (glargine) take up to 6 hours to reach the bloodstream and, like long-acting varieties, do not peak. However, they can last for 36 hours or longer.

Pre-mixed insulins

Premixed insulins, such as Humulin 70/30 or Novolin 70/30, combine a rapid or short-acting insulin with an intermediate-acting insulin. The intermediate-acting insulin controls blood sugar throughout the day, while the rapid-acting insulin controls blood sugar levels at meal times.

Inhaled insulin

Afrezza (insulin) is a form of rapid-acting insulin administered with an inhaler. It starts working within 10-15 minutes, peaks at between 30-90 minutes, and lasts for up to three hours. It is typically used alongside a long-acting insulin.

How is insulin administered?

Insulin cannot be delivered in pill form as it would be digested by the body. Consequently, insulin is injected into the fat under the skin (usually in the upper arm, thighs, buttocks or abdomen). There are a number of devices available to help people with diabetes correctly administer their insulin…