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All About Insulin

Types of insulin, administration with needles, pumps, pens, and why insulin is so expensive

What does insulin do? Help your body turn food into energy, for starters. When you’re diabetic, and you’re either not producing insulin, or your insulin function is off, all sorts of things can go wrong. From needles, to pens, to pumps, to types of insulin, we’re here to empower you with clear answers to all your pressing Qs.

In This Article: 
Definition Causes | Types | Administration | Storage | Alternatives Control Financial Assistance | Fast Facts | Frequently Asked Questions

Featured Voices:
Alvin Powers MDMihail Zilbermint MD, and Irl Hirsch MD

What is insulin?

Insulin is a hormone created by your pancreas that controls the amount of glucose in your bloodstream at any given moment. It also helps store glucose in your liver, fat, and muscles. Finally, it regulates your body’s metabolism of carbohydrates, fats, and proteins. Sound important? That’s because it is.

“Without proper insulin function, your body can’t store glucose in your muscles or liver, but neither can it make any fat. Instead, the fat breaks down and produces, among other things, keto acids,” says endocrinologist Irl Hirsh MD.  If the levels of these acids grow too high, the imbalance can trigger diabetic ketoacidosis, a potentially fatal condition.

When you eat, your blood glucose levels rise, and this leads a typical person’s pancreas to release insulin, so that the sugar can be stored as energy for later use. Without that pancreatic ability, as a person with either type 1 diabetes or advanced type 2 diabetes, your blood sugar levels may rise dangerously high, or drop too low.

Insulin Basics

What causes someone to be prescribed insulin?

If your body doesn’t make insulin or doesn’t make enough, you are eventually diagnosed with type 1 diabetes. It used to be called juvenile diabetes, but new estimates show that as many as half of people with type 1 diabetes are not diagnosed until adulthood. On the other hand, if your body doesn’t use insulin properly, you have type 2 diabetes.

While people with type 1 diabetes need to take insulin to survive, many people with type 2 are able to stave off insulin use or even avoid it altogether by exercising, losing weight, adapting healthier eating habits, or using other prescription medications.

What are the different types of insulin?

The American Diabetes Association (ADA) characterizes insulin by how fast it works. But everyone’s body is different. If you have diabetes, you should expect deviations in the amount of time any medication takes to reach your bloodstream. 

  • Onset is defined as the length of time before insulin hits your bloodstream and begins to lower blood glucose.
  • Peak is the time during which insulin is at its maximum effectiveness at lowering your blood glucose levels.
  • Duration is the length of time insulin continues to lower your blood glucose levels.
  • Rapid-acting insulin begins to affect blood glucose approximately 15 minutes after injection. It peaks in about an hour, and then continues to work for a few more.
  • Short-acting insulin reaches your bloodstream within 30 minutes of injection. It peaks in the 2-3-hour range and stays effective for 3-6 hours.
  • Intermediate-acting insulin includes NPH insulin (neutral protamine hagedorn) which helps control glucose for 10-12 hours. A protamine is a type of protein that slows the action of this insulin.
  • Long-acting insulin enters the bloodstream 1-2 hours after injection and may be effective for as long as 24 hours. An advantage to long-acting insulin is there is no pronounced peak, and it works more like typical pancreatic insulin.
  • Premixed/combination insulin contains a mix of rapid- or short-acting insulin combined with an intermediate-acting insulin. This eliminates the need to draw insulin from more than one bottle.

How do you take insulin?

Many people with diabetes who use insulin self-administer it by injecting it with a syringe. The outside of the syringe is marked with lines denoting the amount of medication in the needle. There are different size syringes that you can choose from with the help of your doctor.

How do you choose the right syringe for injecting insulin?

  1. If your highest dose is near the syringe's maximum capacity, consider buying the next size up in case your dosage increases
  2. If you measure your doses in half units, be careful to choose an appropriate syringe that has the right measurements
  3. When you’re traveling, make sure to match your insulin strength with the correct size syringe if you purchase new syringes in an unfamiliar place

Just as there are different sizes of syringes for administering insulin, there are also varying sizes of insulin needles. Shorter needles usually mean less sting when injecting. The downside is that the shallower the injection is, the longer it takes for the insulin to work. Your doctor will help you find the balance that’s best for you.

How do you take insulin without a syringe?

  • Insulin pens look like large writing pens and can help prevent under- and overdosing. They also don’t require refrigeration, are conveniently prefilled, and are more durable than syringes.
  • Insulin pumps are attached to a thin tube that’s implanted under your skin. Pumps are computerized or motorized, and some models also act as glucose monitors. They deliver insulin before each meal along with small amounts through the course of the day. In the US, about 60% of people with diabetes use some form of insulin pump.
  • Jet injection devices are a good option if you hate needles. A jet injector holds several doses of insulin. After placing it against your skin, you press a button, and the insulin is pushed through.
  • Inhalable insulin comes in a premeasured inhaler and was first approved in 2014. It’s short-acting and usually not covered by insurance, which makes it more cost prohibitive than other types of insulin for most people with diabetes.

Unless you have an insulin pump that also works as a glucose monitor, insulin dosing is based on self-monitoring your blood glucose levels. You can check them by doing finger pricks or wearing a device that continuously monitors them for you.

How should I store my insulin?

  • Keep “current” insulin (like a few days or a week’s supply) at room temperature to help alleviate injection discomfort.
  • Insulin can usually be stored at room temperature for about a month. Once in use, insulin pens should be stored at room temperature. Expiration dates of insulin pens can vary depending upon the type of insulin. For disposable pens, you should discard the entire device when empty or when you reach the expiration date.
  • Store extra insulin (such as a 2–3-week supply or more) in the refrigerator.
  • Don’t expose insulin to excessive cold or heat. (Don’t store it in the freezer or in direct sunlight.)

What are alternative medications for people with diabetes that aren’t insulin?

  • Metformin – a pill that stops sugar production in the liver
  • Glitazones – pills that remove sugar from the bloodstream
  • Sufonylureas and glinides – pills that increase the release of insulin from your pancreas
  • Starch blockers – pills that slow starch absorption
  • Incretin therapies and amvlin analogs – pills and injections that reduce sugar production in the liver and slow food absorption. Types of the former include DPP4 inhibitors (such as Januvia) and GLP1 analogs (like Victoza).
  • SGLT2 inhibitors – pills that are taken before meals that prevent the reabsorption of glucose

What else can I do to control my blood glucose levels?

Food, sleep, and exercise are all of vital importance for regulating your blood sugar when you have diabetes.

  1. Get enough sleep. Evidence shows that lack of sleep can lead to increased secretion of the hormone cortisol, which is inflammatory and can cause greater insulin resistance. Endocrinologist Al Powers MD of Vanderbilt University notes that when you’re deprived of sleep or your sleep is disrupted, your glucose levels tend to go up, whether you have diabetes or not.
  2. Exercise regularly. During exercise, insulin sensitivity is increased, and muscle cells use available insulin more efficiently. When your muscles contract during exercise, they also absorb glucose and use it for energy.
  3. Follow a diabetic-safe diet recommended by your doctor with limited carbohydrates, such as the DASH diet or the Mediterranean diet. Both have been shown to help stabilize blood sugar levels.

What are the drawbacks to insulin treatment for diabetes?

The biggest issue with insulin right now is unaffordability. “A box of rapid-acting insulin can cost $400 without insurance. As so many people continue to lose their health coverage, it’s becoming an enormous problem,” Dr. Zilbermint says.

Consistently rising costs have led some patients to ration their insulin, which can be dangerous and even deadly. The cost of testing strips is also an issue, and both have led to a black market in testing strips and insulin. “It’s illegal,” says Dr. Zilbermint, “but it’s happening.”

Who uses insulin in the US?

  • 7.4 million people in the US use insulin
  • 14% of white people with diabetes use insulin
  • 17% of Latinx people with diabetes use insulin
  • 20% of Black people with diabetes use insulin
  • 24% of people with diabetes who live below the poverty line use insulin

Where can I find help acquiring or paying for insulin?

The ADA has a dedicated page for helping people who need insulin get it, regardless of finances: http://www.insulinhelp.org.

JRDF has a page with a variety of links to organizations who also supply insulin assistance: https://www.jdrf.org/t1d-resources/living-with-t1d/insurance/help-with-prescription-costs/

What severe complications can occur because of rationing or running out of insulin?

Diabetic ketoacidosis is an emergency condition that results if you don’t have enough insulin to regulate your blood sugar. DKA causes your body to break down fat for energy in the absence of insulin. This leads to a dangerous accumulation of acids known as ketones in your blood that can cause your brain to swell and your body to go into shock.

Signs of diabetic ketoacidosis include: 

  • Thirst or a very dry mouth
  • Frequent urination
  • High blood sugar levels
  • High levels of ketones in your urine
  • Fatigue
  • Dry or flushed skin
  • Nausea, vomiting, or stomach pain
  • Difficulty breathing
  • A fruity or acetone odor on your breath (yes, just like nail polish remover)
  • Confusion or acting “drunk” while sober

DKA is so common and can come on so quickly that it is the first sign of Type 1 diabetes in 20% of cases, and the way many type 1 diabetics are first diagnosed with the condition. If you go into diabetic ketoacidosis, don’t try to hide it or make light of it. Treat it as the emergency it is and get to a hospital as soon as possible to recover. “I’ve had people tell me they’re tired of taking insulin, or that they’re rationing it due to cost. In type 1 diabetes, that’s all it takes to end up in a life-threatening situation,” says Dr. Zilbermint.

Another complication facing diabetics who use insulin is the potential for hyperglycemia, also known as “insulin shock,” which involves using too much insulin and causing your blood sugar to drop extremely low. “This can cause coma, seizures, and heart attacks,” says Dr. Powers.

The good news? Once you get to a hospital, doctors can stabilize both conditions quickly, so take them seriously, and make sure your friends and family are educated about your diabetes. Your chosen support network should know how to spot the signs and get you to medical help immediately if you need it and aren’t feeling well enough to advocate for yourself.

What will insulin be like in the future?

Pharmaceutical companies are working on very long-acting versions of insulin that could last for a week. There is also an ultra-fast version of insulin under development that will act in less than 15 minutes.

Another group of researchers is looking at glucose responsive insulin (GRI), which would react to the needs of your body in real time. “It would have nanosensors bound to the insulin so that when insulin is needed, it releases, and when it isn’t, it stops,” according to Dr. Hirsch.

FAQ: Frequently Asked Questions

1. Why is insulin so expensive?

Though reforms are underway in many parts of the US, insulin costs are still prohibitively expensive for many people with diabetes. Reasons include the complexity of the pharmaceutical supply chain and lack of generic substitutes.   

2. What is sliding scale insulin?

Sliding scale therapy is a regimen that prescribes a progressive increase in insulin doses before meals and at bedtime, based on your blood sugar levels.

3. What is an insulin index?

The insulin index gives foods a rating based on how much your blood insulin concentration rises in the two hours after consumption.

4. What is an insulin resistance diet? 

An insulin resistance diet incorporates foods that will help maintain your body’s balance of insulin and blood sugar. Think nourishing calories from veggies, fruit, lean proteins, and healthy fats.

Insulin Fast Facts

  • 7.4 million people in the US use insulin
  • 60% of people with Type 1 diabetes use an insulin pump
  • A single box of insulin can cost $400 without insurance
  • Inability to afford insulin is the main cause of diabetic ketoacidosis
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Patient Guide to Insulin: About Diabetes
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