Takeaways

• Insulin is a hormone that helps blood sugar enter the body’s cells so it can be used for energy. It helps maintain normal blood sugar levels. 

• For people with diabetes, their body could be unable to produce sufficient insulin, could be resistant to the insulin produced, or both conditions could be present. This results in chronically elevated blood sugar levels, which can lead to serious health complications -- this is where insulin therapy may be of benefit.

• There are five different types of insulin, categorized by how long they take to work in the body: rapid-acting, regular- or short-acting, intermediate-acting, mixed, and long-acting insulin.

• Insulin must be injected into the skin (typically into the fatty parts of the body).

• Common side effects of insulin therapy include hyper- and hypoglycemia. Other rarer side effects include insulin allergy, weight gain, skin infections, and lipodystrophy.

• Individuals with type 1 diabetes cannot come off insulin therapy. This is in contrast to those with type 2 diabetes, who may be able to switch to oral hypoglycemic medications or, better still, achieve diabetes remission with appropriate lifestyle changes. 

Diabetes is a metabolic disease in which the body produces insufficient insulin (e.g., type 1 diabetes) or does not respond properly to insulin (e.g., type 2 diabetes). Before 1921, individuals with diabetes did not have access to effective treatment. As a result, many of them lived their lives with chronically elevated high blood sugar levels and experienced unpreventable debilitating complications, like blindness, nerve damage, and kidney failure. However, in 1921, the doom-and-gloom prognosis for diabetes took a 180-degree turn when scientists successfully isolated the hormone insulin. This paved the way for one of the leading medical miracles of the 20th century: the advent of insulin therapy. 

This article highlights everything you need to know about this transformative medical triumph—from what it is, how it works, and the types of insulin therapy available in Singapore. 

What is insulin?

Insulin is a hormone your pancreas makes to help the body use glucose, a type of sugar found in many carbohydrates, for energy.  Here’s how the body of a person without diabetes processes glucose:

1. After eating, the carbohydrates are broken down into glucose, the body’s primary energy source. 

2. Glucose then enters the bloodstream through the small intestine’s lining. 

3. The pancreas responds to this rise in blood sugar levels by releasing insulin, which brings glucose into the body’s cells to use as energy (fuelling various bodily functions, like breathing, thinking, and running). Blood sugar levels fall to “normal” blood glucose levels.

Why is insulin important in diabetes?

As mentioned earlier, in diabetes, either the pancreas doesn’t make enough insulin, or the body’s cells can’t use insulin very well, i.e. insulin resistance. Since insulin is responsible for the uptake of glucose from the blood, both instances can result in blood glucose levels that are too high (i.e., hyperglycemia). Over time, this could permanently damage parts of the body, like the eyes, nerves, kidneys, and blood vessels. Hyperglycemia is also a known risk factor for cardiovascular disease and cancer. These serious health complications thus highlight the crucial role insulin therapy could play in a comprehensive diabetes management plan; keeping blood sugar levels within a normal range could help individuals with diabetes enjoy a better quality of life. 

Types of insulin for diabetes treatment

Before diving into the types of insulin available for diabetes treatment, it’ll be helpful to understand how insulin levels typically fluctuate in a person without diabetes. To keep the blood sugar levels in a narrow range overnight, during fasting, and between meals (i.e., in the absence of food), the pancreas constantly releases a low background level of insulin. Then, when a person eats a carbohydrate-rich meal, the blood sugar levels rise, causing a surge of insulin. The insulin levels rapidly climb and peak in about 45 minutes to an hour before falling back to the background or basal levels. 

Unfortunately, while current insulin replacement therapy approximates normal insulin levels, it cannot entirely replicate the natural rise and fall just yet. You’ll understand why once you see the five different types of insulin currently available; they all have different onset of action (i.e., length of time it takes for a medicine to start working) and duration of action (i.e., length of time a medicine is effective): 

1. Rapid-acting insulin: Taken just before meals. Starts working in about 20 minutes, and its effect will peak at 90 minutes. Works for a total of four hours. 

2. Regular- or short-acting insulin: Taken just before meals. Starts working in about 30 minutes, peaks in about three hours, and can last six hours. 

3. Intermediate-acting insulin: Starts working in about three hours, peaks at about eight hours, and works for 16 hours. Intermediate-acting insulin are also known as “basal insulin” since they provide low, background levels of insulin.

4. Long-acting insulin: Starts working in about two hours. Provides a slow, steady release of insulin with no apparent peak action and can last up to 24 hours. Ultra-long-acting insulin can work for 36 hours. Similarly to Intermediate-acting insulin, long-acting insulin and ultra-long-acting insulin are also known as “basal insulin” since they provide low, background levels of insulin.

5. Mixed insulin: As its name suggests, mixed insulin is a mixture of different types of insulin. This type of insulin helps to reduce the number of injections required per day.

The type of insulin a person with diabetes will be prescribed depends on several factors, including their lifestyle, type of diabetes, and typical daily blood sugar fluctuations. 

Table of insulin types (single type)

Table of mixed insulin (these medications contain a mix of different types of insulin)

How is insulin administered?

Insulin breaks down too easily in the stomach to be given as a tablet. So, all insulin is taken with a needle injected into the skin. 

The most traditional way to use insulin is with a syringe, needle, and a vial—similar to how traditional vaccinations are given. Another option is to use pen-style injectors -- this is the more commonly used type of insulin these days given its convenience. For people who take insulin many times each day, an insulin pump may be a good option. The needles are very short and thin, regardless of the system. Each person will have their own preferences and needs, so it's important to talk with a doctor about the right method for each individual.

Insulin injections have to go into fatty parts of the body, such as the hip, buttock, stomach, thigh, or upper arm. These areas are the best at absorbing insulin quickly and evenly. It’s important to rotate injection sites and use different areas. If one spot is injected too much, it can cause problems with the fat called lipodystrophy (a condition in which the amount and/or distribution of fat tissue in the body is abnormal). 

There are various different insulin regimens (frequency of administering insulin), and the regimen may affect the type of insulin used. Depending on your unique requirements, your doctor will be able to advise you on the most appropriate insulin regimen. 

How much does insulin cost?

* Prices are based on data from the Pharmaceutical Society of Singapore (updated 2020).

How should insulin be stored?

Insulin should be stored in the refrigerator, between 5oC and 8oC per manufacturer recommendations. However, many people find that injecting a cold liquid is more painful, so they store one vial of insulin at room temperature (below 30oC). The manufacturers have said this is acceptable. Open vials or pen refills last for 28 days and should be thrown away after that time. 

Insulin should never be stored in direct sunlight. Insulin should never be frozen. If insulin becomes discolored (not clear) or if it is frozen, it should be thrown away. 

Side effects of insulin therapy and what to do

WARNING: Please call 995 (if you are based in Singapore) if there is concern for a medical emergency.

The most common side effects of insulin therapy typically result from having either too much insulin or too little:

• High blood sugar: If a person has too little insulin, they experience high blood sugar (hyperglycemia). If blood sugar becomes very high for a prolonged period, generally over 300 mg/dL (16.7 mmol/L), a person may be at risk for diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic syndrome (HHS). These are both medical emergencies that can result in coma, seizure, and death. Earlier signs can include feeling very thirsty and frequent urination.

• Low blood sugar: If a person takes too much insulin, they have low blood sugar (hypoglycemia). The symptoms are a little bit different in everyone but commonly include feeling tired or confused, headaches, dizziness, hunger, nausea, or clumsiness. If blood sugar continues to fall, the person can have a seizure, lose consciousness, or even die.

Thankfully, individuals on insulin therapy may be able to pre-empt both side effects by pro-actively—and periodically—monitoring their blood sugar levels. Those worried about hassle and pain can find comfort in continuous glucose monitors, which can measure up-to-the-minute glucose readings day and night, for days at a stretch.

Those who discover their blood sugar levels are slightly elevated could try exercising to bring their readings down. On the other hand, those who discover their blood sugar levels are on the lower side could try using the 15-15 rule. First, eat 15 g of sugar (check food labels), then recheck blood sugar in 15 minutes. Repeat until blood sugar is over 70 mg/dL (3.9 mmol/L), then have a meal. 

However, note that these are general guidelines. Please seek prompt medical help whenever needed. Also, always consult your primary healthcare provider for advice on how you could better manage your blood sugar levels. In some instances, your doctor may end up adjusting your insulin dosages. 

Beyond hyper- or hypoglycemia, insulin therapy may also cause other undesirable effects, like:

• Sometimes, individuals develop an allergy to a specific type of insulin and have to try another one.

• Insulin can also cause weight gain, usually 1-3 kg.

• Because the skin is broken when injecting insulin, infections can occur. To prevent this, use a clean needle every time and always clean the injection site.

• Insulin injections can also change how the fat under the skin looks. It can become either thicker or thinner, and a person using insulin may notice a soft, smooth area or other skin changes. To prevent these problems, be sure to rotate injection sites.

Is It Possible To Stop Insulin Treatment for Diabetes?

For people with type 1 diabetes, insulin treatment should continue for life, with or without an insulin pump. However, dosages may need to be adjusted throughout life, for example, if a person becomes pregnant, loses or gains weight, or has problems with hypoglycemia.

For people with type 2 diabetes, improving diet, exercising more, and losing weight can sometimes mean that it is possible to switch to oral medications alone, and that insulin therapy is no longer required. Sometimes with even more drastic improvement, it is possible to go into diabetes remission which may mean that a person no longer needs insulin or other medications. 

Whether you’re looking to find out if insulin therapy is suitable for you, switch up insulin types for improved blood sugar control, or work toward diabetes remission, NOVI Magnum can help. Click here to book a consultation.