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What is Insulin Glargine?
Updated on June 26, 2023
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What is Insulin Glargine?

Key Takeaways

Insulin Glargine is a medicine used to manage blood sugar levels in people with diabetes

It is a man-made version of the insulin our bodies naturally produce. It helps to supplement a shortage of natural insulin, often found in patients with diabetes.1

It is administered via injection in regular doses. This is because Insulin Glargine is a long acting insulin or “basal” insulin, which the body maintains at a set level to process the normal amount of glucose produced by the human body. 

This is in contrast to fast-acting or “bolus” insulin, which is produced as needed in response to spikes in blood sugar, such as when consuming lots of carbohydrates.2

Insulin Glargine is available under the brand names Lantus, Toujeo, and more. It is not available as a generic medicine yet and requires a prescription from your healthcare provider to purchase.

Is Insulin Glargine Used for Type 1 or Type 2 Diabetes?

Insulin Glargine is used to help treat both type 1 and type 2 diabetes

Type 1 diabetes is when the human body does not produce the normal amount of both short and long acting insulin. Insulin Glargine is used in diabetes treatment to replace the missing long acting insulin and offset high blood sugar.

Type 2 diabetes is when the human body does not use the insulin it produces normally. In such cases, Insulin Glargine may be part of the treatment plan alongside other diabetes medications.

The FDA has approved Insulin Glargine for use in children aged six and older, as well as adults. There are some studies on the efficacy and safety of Insulin Glargine on younger children, but such use is not yet approved for general use.3,4

How Does Insulin Glargine Work?

In both type 1 and type 2 diabetes, Insulin Glargine is a synthetic form of human basal insulin that can be injected to replace or increase the missing insulin in the body.

Insulin is a hormone produced by the pancreas. Its role in the body is to deliver glucose from the bloodstream into various cells and parts of the body to be converted into energy. 

When we eat, carbohydrates and sugars from the food enter our bloodstream. If there is not enough insulin to control it, these sugars can build up, leading to high blood sugar or 'hyperglycemia.'5

Insulin is either insufficient or inefficient in two ways, depending on the type of diabetes:

  • Type 1 diabetes - The disease causes the body to destroy insulin-producing cells in the pancreas, causing the body to produce insulin at a decreased level overall. 
  • Type 2 diabetes - Organs develop an “insulin resistance,” which means the glucose delivered by insulin to cells is not properly absorbed. In this case, the body attempts to create more insulin to offset insulin resistance but is still unable to keep up with the buildup of glucose in the bloodstream.

How Should Insulin Glargine Be Administered?

Since Insulin Glargine works by replacing the long-acting insulin in the body, it is meant to be administered in set daily doses. It is not to be confused with fast-acting insulin that may be administered in response to a specific spike in blood sugar.

Insulin Glargine is administered via subcutaneous injection (injected into fatty tissue, not veins)

Avoid injecting it into muscle, bruised skin, or previous injection sites within the same week to allow the injection site to recover between doses. It is recommended to inject Insulin Glargine into adipose tissue in the upper arm, thigh, or stomach and alternate between injection sites.6

Insulin Glargine stabilizes basal insulin and lasts for 24 hours, so it should be administered at roughly the same time daily. Ask your doctor or pharmacist for specific instructions regarding drug interactions with other over the counter medications.

The dose will depend on your doctor’s prescription but will generally not change day to day. Your care team will calculate the exact medication dosage, which should be explicitly followed.

Most patients taking insulin glargine may also take other oral antidiabetic drugs for diabetes treatment. Follow the instructions of your doctor or pharmacist to avoid medication errors.

Can Insulin Glargine Be Given Twice Daily?

There are attempted studies on the efficacy of twice-a-day doses of Insulin Glargine, but these are inconclusive and do not significantly improve blood sugar control.7,8 For now, the recommendation is to maintain a daily dose.

What Are the Side Effects of Insulin Glargine?

The most common side effect of Insulin Glargine is severe hypoglycemia or low blood sugar. This could be a result of too much insulin glargine. Hypoglycemia may result in:

  • Anxiety
  • The clamminess of hands and feet
  • Disorientation
  • Dizziness or light-headedness
  • Heightened irritability
  • Hunger, especially if you’ve just eaten
  • Mood swings
  • Rapid weight gain
  • Muscle weakness

Allergic reactions to insulin are rare, though itchiness and lumps may form at the injection site, and one may experience trouble breathing. This common occurrence goes away, but if the issue persists or is difficult to manage, contact your health provider.

What Precautions Should Be Taken When Using Insulin Glargine?

Though diabetic patients should be dependent on their health provider for advice regarding dosages and medicine, the diabetic patient also has a role in monitoring their blood sugar level and participating in their own blood sugar control. 

Self-monitoring of blood glucose levels can be done in two ways:

  1. Blood Glucose Monitoring (BGM) - BGM makes use of a small, portable device that can be used to prick one’s finger. The device then uses the blood sample to display a measurement of your blood glucose level.
  1. Continuous Glucose Monitoring (CGM) - CGM utilizes a sticky patch sensor that monitors glucose levels under the skin. It can transmit live readings directly to an app or recording device. The constant monitoring is an advantage, but CGM devices tend to be more expensive than BGM and are less accurate when detecting low blood sugar.9

A diabetic care team then uses the results of glucose control monitoring to adjust the recommended initial dose or treatment plan as necessary. Other insulin glargine products or oral diabetes medicines may supplement lantus insulin glargine to improve glycemic control.

It is also recommended to avoid drinking alcohol, non diet soda, and other high-sugar food or drink to improve blood sugar control. Changes in sugar and alcohol consumption, stress, sickness, and daily activity should also be reported to your doctor.

Is Insulin Glargine Safe?

Yes. However, Insulin Glargine is not yet approved for use in children below six years of age. 

Additionally, any insulin glargine medication dosage should not be taken when the patient shows signs of hypoglycemia or low blood sugar. Some persons may also have an allergic reaction to insulin glargine products. Call your doctor in the case of insulin allergy, insulin glargine overdose, or other immediate side effects.

How to Store and Dispose of Insulin Glargine

Insulin Glargine doses should be refrigerated before use but do not freeze insulin. They should be kept in only the injection pen or the vial that they are purchased in. Unrefrigerated pens can still be used for up to 28 days, provided they are not kept in direct sunlight or extreme heat.

When administering Insulin Glargine, ensure that the injection site is sterile by using an alcohol swab. If another person administers the injection, they should also sterilize their hands and handle only the injection pen and the injection site. 

Gloves are recommended for healthcare providers or individuals not related to the patient who are administering the insulin. Do not reuse needles and syringes.

Used needles should be disposed of in puncture-resistant containers such as glass containers or thick plastic bottles. Your healthcare provider will provide additional details on how to dispose of used needles and remaining doses of the medicine.

Updated on June 26, 2023
Dr. Rizza Mira
Dr. Rizza Mira
Medical Reviewer
Dr. Rizza Mira is a medical doctor and a general practitioner who specializes in pediatrics, nutrition, dietetics, and public health.

As a pediatrician, she is dedicated to the general health and well-being of children and expecting parents. She believes that good nutrition, a healthy lifestyle, and prevention of illness are key to ensuring the health of children and their families.

When she’s not in the hospital, Rizza advocates and mobilizes causes like breastfeeding, vaccination drives, and initiatives to prevent illness in the community.
Will Hunter
Will Hunter
Content Contributor
Will is a content writer for KnowYourDNA. He received his B.A. in Psychology from the University of California, Los Angeles. Will has 7 years of experience writing health-related content, with an emphasis on nutrition, alternative medicine, and longevity.
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