This document provides an overview of insulin, including its function in the body, production in the pancreas, and role in diabetes. It discusses the different types of insulin (fast-acting, intermediate-acting, long-acting) and how they vary in onset, peak effectiveness, and duration. Potential side effects of insulin therapy like hypoglycemia and weight gain are also outlined. The document concludes by looking at who needs insulin therapy and various methods of insulin delivery.

1. Insulin
Author:
Danyar Abdulrahman
Supervisor : Dr.Sara
Kurdistan Regional Government
Ministry of High Education
CihanUniversity
Medical Laboratory Science

2. An overview of insulin
The role of insulin in the body is to allow glucose in
the blood to enter cells, providing them with the
energy to function. A lack of effective insulin plays a
key role in the development of diabetes.
Insulin is a type of hormone. Hormones are
chemical messengers that instruct certain cells or
tissues to act in a certain way that supports a
particular function in the body.
Insulin is essential for staying alive.
In this article, we look at how the body produces
insulin and what happens when not enough of it
circulates, as well as the different types that a person
can use to supplement insulin.
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3. What is insulin?
Insulin is a chemical messenger that allows cells to absorb glucose,
a sugar, from the blood.
The pancreas is an organ behind the stomach that is the main source
of insulin in the body. Clusters of cells in the pancreas called islets
produce the hormone and determine the amount based on blood
glucose levels in the body.
The higher the level of glucose, the more insulin goes into
production to balance sugar levels in the blood.
Insulin also assists in breaking down fats or proteins for energy.
A delicate balance of insulin regulates blood sugar and many
processes in the body. If insulin levels are too low or high,
excessively high or low blood sugar can start to cause symptoms. If
a state of low or high blood sugar continues, serious health
problems might start to develop.
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4. Insulin problems
In some people, the immune system attacks the islets, and they cease to produce insulin or do not produce enough.
When this occurs, blood glucose stays in the blood and cells cannot absorb them to convert the sugars into energy.
This is the onset of type 1 diabetes, and a person with this version of diabetes will need regular shots of insulin to survive.
In some people, especially those who are overweight, obese, or inactive, insulin is not effective in transporting glucose into the
cells and unable to fulfill its actions. The inability of insulin to exert its effect on tissues is called insulin resistance.
Type 2 diabetes will develop when the islets cannot produce enough insulin to overcome insulin resistance.
Since the early 20th century, doctors have been able to isolate insulin and provide it in an injectable form to supplement the
hormone for people who cannot produce it themselves or have increased insulin resistance.
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5. Types of insulin
A person can take different types of insulin based on how long they need the effects of the supplementary hormone to last.
People categorize these types based on several different factors:
*speed of onset, or how quickly a person taking insulin can expect the effects to start.
*peak, or the speed at which the insulin reaches its greatest impact
*duration, or the time it takes for the insulin to wear off
*concentration, which in the United States is 100 units per milliliter (U100)
the route of delivery, or whether the insulin requires injection under the skin,into a vein, or into the lungs by inhalation.
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6. Three main groups of insulin are available.
Fast-acting insulin
The body absorbs this type into the bloodstream from the subcutaneous tissue extremely quickly.
People use fast-acting insulin to correct hyperglycemia, or high blood sugar, as well as control blood sugar spikes after eating.
This type includes:
Rapid-acting insulin analogs: These take between 5 and 15 minutes to have an effect. However, the size of the dose impacts
the duration of the effect. Assuming that rapid-acting insulin analogs last for 4 hours is a safe general rule. Examples: Aspart
(Novolog), Lispro (Humalog).
Regular human insulin: The onset of regular human insulin is between 30 minutes and an hour, and its effects on blood sugar
last around 8 hours. A larger dose speeds up the onset but also delay the peak effect of regular human insulin. Examples:
Humulin R, Novolin R
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7. Intermediate-acting insulin
This type enters the bloodstream at a slower rate but has a longer-lasting effect. It is most effective at managing blood sugar overnight, as well as
between meals.
Options for intermediate-acting insulin include:
NPH human insulin: This takes between 1 and 2 hours to onset, and reaches its peak within 4 to 6 hours. It can last over 12 hours in some cases.
A very small dose will bring forward the peak effect, and a high dose will increase the time NPH takes to reach its peak and the overall duration of
its effect. Examples: Humulin N, Novolin N.
Pre-mixed insulin: This is a mixture of NPH with a fast-acting insulin, and its effects are a combination of the intermediate- and rapid-acting
insulins. The mixtures can be in various combinations from 50:50 to 75:25 or 70:30. An example includes Novolog 70/30.
Long-acting insulin
While long-acting insulin is slow to reach the bloodstream and has a relatively low peak, it has a stabilizing “plateau” effect on blood sugar that
can last for most of the day. Glargine (Lantus) is an example.
It is useful overnight, between meals, and during fasts.
Long-acting insulin analogs are the only available type, and these have an onset of between 1.5 and 2 hours. While different brands have different
durations, they range between 12 and 24 hours in total.
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8. What are the side effects of insulin therapy?
Many people with diabetes take insulin to help manage their blood sugar levels. However, insulin therapy can cause a range of side effects.
Insulin is a hormone that helps regulate the amount of sugar, or glucose, in the blood. Insulin has a counterpart called glucagon, a hormone that works in
the opposite way.
The body uses insulin and glucagon to ensure that blood sugar levels do not get too high or low and that cells receive enough glucose to use for energy.
When blood sugar is too low, the pancreas secretes glucagon, which causes the liver to release glucose into the bloodstream. However, people
with diabetes might need to take supplementary insulin to help keep their blood sugar levels within a normal range.
In this article, we look at the side effects, risks, and myths of insulin therapy and provide tips for taking insulin safely.
Many different types and brands of insulin are available in the United States.
The side effects that a person might experience depend on the type of insulin they are taking.
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9. Common side effects include:
*initial weight gain as the cells start to take in glucose
*blood sugar that drops too lowTrusted Source,
or hypoglycemia
*rashes, bumps, or swelling at an injection site
*anxiety or depression
*a cough when taking inhaled insulin
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10. Hypoglycemia when taking insulin
Insulin shots cause the cells in the body to absorb more glucose from the bloodstream. As a result, taking too much or
administering an injection at the wrong time may cause an excessive drop in blood sugar.
If a person’s blood sugar level drops too low, they may experience symptoms, such as:
*dizziness
*trouble speaking
*fatigue
*confusion
*pale skin
*sweating
*twitching muscles
*seizure
*loss of consciousness
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11. Other possible complications
There is also the possibility that taking insulin will cause more severe side effects, although these are less common.
Fat necrosis may develop in people who regularly inject insulin. This condition causes a painful lumpTrusted Source to grow in
the subcutaneous tissue, which is just below the skin’s surface.
A 2013 review compared insulin therapy with metformin treatment. Metformin is another glucose-lowering treatment for people
with type 2 diabetes.
These researchers found that the insulin therapy group in the study had an increased risk of several complications, including:
*heart attack
*stroke
*eye complications
*kidney problems
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12. Who needs to take insulin?
Diabetes impairs insulin production by the pancreas and use of this essential hormone by the body. The condition causes high blood sugar levels.
However, not every person with type 2 diabetes will need to take insulin. People with type 1, on the other hand, will have to supplement their insulin
supply for the rest of their lives.
There are three main types of diabetes:
Type 1 diabetes: Typically starts in childhood when a person does not produce enough insulin. Usually results from the body’s immune system attacking
an otherwise healthy pancreas.
Type 2 diabetes: Can develop at any age but 45 yearsTrusted Source is the average age of onset. Either the pancreas does not produce enough insulin, or
the body’s cells become resistant to its actions.
Gestational diabetes: Occurs during pregnancy and makes it harder for a woman’s body to respond to insulin. Typically stops after childbirth but
increases a woman’s risk of developing type 2 diabetes.
Type 1 and type 2 diabetes are usually lifelong conditions. According to the Centers for Disease Control and Prevention (CDC), more than 30 million
people in the United States have diabetes. Type 2 diabetes is the most common, accounting for 90–95 percentTrusted Source of those with diabetes.
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13. Insulin delivery devices
People with type 1 diabetes require daily insulin therapy to maintain regular blood sugar levels. However, the exact treatment regimen will
vary from person to person.
An individual can deliver their insulin to their body through a pump. This is a machine that provides the hormone through a port, removing
the need for injections. Some pumps are automatic, while others require more user input.
Some individuals may need to supply two to four doses every day. Extra shots of rapid- or short-acting insulin may be necessary at mealtimes.
People also use injections, pens, and inhalers to take insulin.
Types of insulin
A doctor can help customize a safe and effective insulin therapy regimen for a person with type 1 diabetes. According to the American
Academy of Family Physicians, there are several different types of insulin that people can use separately or in combination.
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14. These includeTrusted Source:
*Rapid-acting insulins that start to work within 15 minutes and can last around 3–5 hours.
*Short-acting insulins that take 30–60 minutes to start working and have a duration of 5–8 hours.
*Intermediate-acting insulins that take 1–3 hours to start working but last 12–16 hours.
*Long-acting insulins that start to work in about 1 hour and can last 20–26 hours.
*Premixed insulins that combine a rapid- or short-acting insulin with a longer-lasting one.
A doctor will prescribe one of these insulins or a mixture alongside a carefully controlled schedule.
Following this closely will reduce the risk of side effects and complications.
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15. SOURCES
1- Bai, X., et al. (2018). The association between insulin therapy and depression in patients with type 2 diabetes
mellitus: A meta-analysis.
2- Currie, C. J., et al. (2013). Mortality and other important diabetes-related outcomes with insulin vs other
antihyperglycemic therapies in type 2 diabetes.
3- Hanson, P. (2014). Painful fat necrosis resulting from insulin injections.
4- Insulin basics. (2019).
5 Lebovitz, H. E. (2011). Insulin: Potential negative consequences of early routine use in patients with type 2
diabetes.
6 Low blood glucose (hypoglycaemia). (2016).
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