Insulins: Uses, common brands, and safety info

Insulin is a naturally occurring hormone that helps the body regulate blood sugar levels and provides cells with energy. Diabetes mellitus, more commonly known simply as diabetes, is a condition in which the body’s ability to produce or respond to the hormone insulin is impaired, resulting in high blood sugar. In people with Type 1 diabetes, the pancreas no longer makes insulin and insulin shots are needed to utilize the sugars from food. Those with Type 2 diabetes may still make insulin, but it may not be in sufficient amounts or their bodies don’t respond well to the insulin that is available (known as insulin resistance). About 30% of people with Type 2 diabetes also need insulin injections.

This table lists commonly used insulins followed by information on how they work, what conditions they treat, safety, and cost.

RELATED: Type 1 vs. Type 2 diabetes

What is insulin?

Insulin is a natural hormone secreted by specialized cells, called beta cells, located in the pancreas. Insulin regulates many functions in the body that provide cells with the energy they need to live and grow. In people without diabetes, insulin production and release is a very complex process, allowing the body to carefully maintain blood sugar levels to meet its needs. 

Since the 1920s, when researchers identified and isolated insulin, medical science has made great strides in creating new insulin therapy products that allow people with diabetes who are insulin-dependent to maintain near-normal control over their blood sugars.

How does insulin work?

Immediately following a meal, food that is eaten, particularly carbohydrates, quickly breaks down into a specific type of sugar called glucose that is absorbed into the bloodstream. This rapid rise in blood glucose causes insulin to be released from the pancreas. The insulin allows cells in the body, such as muscle cells, to absorb the glucose to use as a source of energy. Insulin has other effects, but mainly it controls how the body utilizes glucose. 

In people with diabetes, if the body does not produce enough insulin or does not use it efficiently, blood glucose levels increase and the cells go without the glucose they need to function properly. If blood glucose levels remain too high over time, a state known as hyperglycemia, this may increase the risk of heart disease, stroke, and other health problems. 

To overcome the problems associated with high blood glucose levels, people with Type 1 diabetes require insulin by injection or by using an insulin pump. Those with Type 2 diabetes may respond to lifestyle changes to reduce high blood glucose levels, such as diet and exercise, or they may require pills, insulin, or a combination of medicines. 

RELATED: What are normal blood glucose levels?

What are insulins used for?

• Type 1 diabetes

• Type 2 diabetes

• Gestational diabetes (women who develop diabetes during pregnancy)

Types of insulins

Rapid-acting insulins

Rapid-acting insulins are insulin analogs or slightly modified forms of human insulin, that act quickly and predictably. They begin to work approximately 15 minutes after injection, peak in about one to two hours, and last between two to four hours. Rapid-acting insulins cover meals eaten at the same time as the injection and are often used with longer-acting insulin. These insulins are the most common insulins used in insulin pumps (a small external device that delivers insulin through a thin tube placed under the skin).

Common brand names in this class:

• Humalog and Admelog (insulin lispro)

• Novolog and Fiasp (insulin aspart)

• Apidra (insulin glulisine)

Short-acting insulins

Short-acting insulins (also called regular insulins) typically reach the bloodstream within 30 minutes after injection, peak between two to three hours,  and last for approximately three to six hours. These insulins cover meals eaten within 30 to 60 minutes and are often used with a longer-acting insulin. 

Common brand names in this class:

• Humulin R, Novolin R, and ReliOn/Novolin R (regular human insulin)

• Velosulin BR (buffered regular human insulin for use in the insulin pump)

Intermediate-acting insulins

Intermediate-acting insulins typically reach the bloodstream about two to four hours after injection, peak four to 12 hours later, and last for about 12 to 18 hours. These cover insulin needs for about half the day or overnight. They are often used with a rapid- or short-acting insulin. 

Common brand names in this class:

• Humulin N,  Novolin N, and ReliOn/Novolin N (NPH human insulin)

Long-acting insulins

Long-acting insulins, also called basal or background insulins, do not have a peak like shorter-acting insulins. They typically reach the bloodstream several hours after injection and work to lower glucose levels up to 24 hours. These are often combined with rapid- or short-acting insulin.

Common brand names in this class:

• Lantus and Basaglar (insulin glargine)

• Levemir (insulin detemir)

• Tresiba (insulin degludec)

• Humulin R U-500 (concentrated regular human insulin)

Ultra long-acting insulin

Ultra long-acting insulin reaches the bloodstream in about six hours, does not peak, and lasts 36 hours or longer. 

Common brand name in this class:

• Toujeo U-300  (concentrated insulin glargine)

Premixed insulins

Premixed insulins combine two different types of insulin, a rapid- or short-acting insulin with an intermediate-acting insulin, to provide meal-time coverage plus coverage for longer in the day. These are usually taken two or three times a day before mealtime. The first number in the name tells the percentage of the intermediate-acting insulin, the second number the percentage of the rapid- or short-acting insulin (e.g., Novolog Mix 70/30 contains 70% NPH and 30% insulin aspart).

Common brand names in this class:

• Humalog Mix 75/25 – 75% NPH, 25% Humalog (lispro)

• Novolog Mix 70/30 – 70% NPH, 30% Novolog (aspart)

• Humulin 70/30 – 70% NPH, 30% regular

• Novolin 70/30 – 70% NPH, 30% regular

Rapid-acting inhalation powder

Rapid-acting inhaled insulin peaks in the blood in about 15 to 20 minutes and lasts about two to three hours. It must be used along with long-acting insulin in people with Type 1 diabetes.

Common brand name in this class:

• Afrezza inhalation powder (insulin human)

Who can take insulins?

People with Type 1 diabetes

All those with Type 1 diabetes, regardless of age, must take insulin. The beta cells in the pancreas no longer make insulin and in order to manage blood glucose levels, insulin must be injected or infused by an insulin pump. 

People with Type 2 diabetes

Type 2 diabetes is typically a progressive disease and most do not require insulin when first diagnosed. Blood glucose levels are often manageable with lifestyle changes such as more careful meal planning and exercise. Antidiabetic drugs, such as oral medications like metformin or non-insulin injectables, may be added if blood glucose level goals are not being met. Because Type 2 diabetes is a progressive disease, at some point the production of insulin in the pancreas may not be sufficient and insulin injections may be necessary.  

RELATED: Can you reverse diabetes?

Pregnant women with gestational diabetes

Gestational diabetes refers to diabetes that is diagnosed during a woman’s pregnancy. Similar to Type 2 diabetes, the insulin present may not be sufficient to maintain normal blood glucose levels and ensure the cells are receiving the fuel they need. Often insulin injections are necessary for the duration of the pregnancy to protect both the mother and the baby’s health.

Children and adolescents

Children and adolescents with Type 1 diabetes are dependent on insulin therapy to live. The International Society for Pediatric and Adolescent Diabetes (ISPAD) recommends that all age groups, including children, be given insulin therapy that provides as close to normal blood glucose levels as possible. 

RELATED: Your child was diagnosed with Type 1 diabetes. What’s next?

Are insulins safe?

The most serious risk of taking insulin is low blood sugar, or hypoglycemia. If untreated, low blood sugar can be a medical emergency. Low blood sugar can usually be treated quickly by drinking or eating a food high in sugar (e.g., orange juice or candy). There are also products, such as glucose tablets or glucagon for injection, that healthcare providers may recommend for insulin users to have on hand. Other serious risks with taking insulin are hypersensitivity (severe allergic) reactions and hypokalemia (low blood potassium levels).

Insulin restrictions

Do not use insulin if you:

• Have hypoglycemia (low blood sugar).

• Have hypersensitivities (allergies) to any of the ingredients.

Can you take insulin while pregnant or breastfeeding?

• Although no insulin is formally approved by the FDA for use during pregnancy, it’s generally considered safe and effective in pregnant women; insulin is the traditional first-choice drug for treating gestational diabetes.

• Insulin may be used while breastfeeding.

Are insulins controlled substances?

• Insulins are not controlled substances.

Common insulin side effects

• In a recent survey, SingleCare found that gastrointestinal side effects, loss of appetite, and dark urine were the most commonly reported side effects of insulin.

• Injection site reactions (redness, swelling, or itching)

• Injection site lipodystrophy (skin thickening or pits at site)

• Myalgia (muscle pain)

• Pruritus (itching)

• Rash 

• Upper respiratory infection

• Weight gain 

• Headache 

• Peripheral edema (swelling of lower legs or hands)

• Hypersensitivity reaction (allergic reaction)

• Flu-like symptoms

Serious reactions (may need to seek medical help)

• Hypoglycemia (low blood sugar)

• Hypokalemia (low blood potassium levels)

• Hypersensitivity reaction (allergic reaction)

• Anaphylaxis (severe allergic reaction requiring immediate medical help)

How much do insulins cost?

The cost of insulin can vary significantly based on the type used (e.g., human insulin is generally less expensive than insulin analogs such as Humalog or Lantus), and the delivery method (e.g., vials are generally less expensive than the same amount of insulin in prefilled insulin pens.) Insulin costs also may vary depending on the type of insurance, since many plans utilize formularies that may price similar insulin products differently depending on the “preferred” supplier (e.g., Humulin N may be priced higher than Novolin N if Novo Nordisk is the preferred supplier). For people without health insurance, insulin can cost anywhere from $25 to more than $300 per vial. Underinsured or uninsured patients can use free SingleCare coupons to save money on insulin and other diabetes needs.