A close-up image of two vials of insulin glargine and a blood glucose meter.

What is insulin Glargine?

Insulin glargine, also known as glargine insulin, is a long-acting insulin analog used to manage diabetes effectively. Unlike short-acting insulins, glargine insulin has a slow onset and prolonged duration of action, providing a consistent level of insulin in the body over an extended period.

This type of insulin is typically administered via subcutaneous injection once a day at the same time to help control blood sugar levels throughout the day and night. Its mechanism of action involves mimicking the natural insulin produced by the pancreas, allowing glucose to enter cells for energy production, thus regulating blood sugar levels.

The significance of insulin glargine in diabetes treatment lies in its ability to stabilize blood sugar levels, reduce the risk of hyperglycemia, and prevent complications associated with uncontrolled diabetes.

How Insulin Glargine Works

Insulin glargine is a long-acting insulin analog that works by mimicking the action of naturally produced insulin in the body. Here's how insulin glargine works:

  1. Slow and Steady Release: When injected subcutaneously (under the skin), insulin glargine forms microprecipitates in the tissue. These microprecipitates slowly dissolve, releasing insulin into the bloodstream over an extended period.

  2. Steady Basal Insulin Levels: Insulin glargine provides a consistent level of basal insulin throughout the day, helping to regulate blood sugar levels between meals and during periods of fasting.

  3. Reduced Risk of Hypoglycemia: Its steady and prolonged action helps reduce the risk of hypoglycemia (low blood sugar levels) compared to shorter-acting insulins.

  4. 24-Hour Coverage: Insulin glargine typically provides glucose-lowering effects for up to 24 hours after injection, making it suitable for once-daily dosing in most individuals with diabetes.

  5. Maintains Circadian Rhythm: Insulin glargine is designed to closely mimic the body's natural circadian rhythm of insulin secretion, providing a more physiologic insulin profile compared to other insulins.

Administration of Insulin Glargine

  1. Injection Site: The recommended injection sites for insulin glargine are usually the abdomen (except for the area around the navel), thighs, or upper arms. Rotating injection sites helps prevent tissue damage and ensures consistent absorption of insulin.

  2. Preparation: Before administering insulin glargine, it's important to check the expiration date and visually inspect the insulin for any particles or discoloration. Gently roll the insulin vial or pen between your hands to mix the contents, but do not shake vigorously, as this can cause air bubbles.

  3. Dosage: The dosage of insulin glargine should be prescribed by a healthcare professional based on individual insulin needs, blood glucose levels, and other factors. Insulin glargine is available in vials or prefilled pens, and the dose can be adjusted as needed.

  4. Injection Technique: Clean the injection site with an alcohol swab and allow it to dry. Pinch a fold of skin at the injection site and insert the needle at a 45 to 90-degree angle, depending on the needle length and the amount of subcutaneous fat. Inject the insulin slowly and steadily, and hold the needle in place for a few seconds after injecting to ensure the full dose is delivered.

  5. Storage: Insulin glargine should be stored according to the manufacturer's instructions, usually in the refrigerator before opening. Once opened, it can be stored at room temperature for a certain period, but it should be discarded after the specified time to maintain potency and safety.

  6. Monitoring: Regular monitoring of blood glucose levels is essential when using insulin glargine to ensure optimal glycemic control and adjust insulin doses as needed under the guidance of a healthcare provider.

Comparing Insulin Glargine with Other Insulins


Insulin Glargine (Lantus)

Insulin Detemir (Levemir)

Insulin Aspart (NovoLog)

Insulin Lispro (Humalog)

Onset of Action

1 - 2 hours

1 hour

10 - 20 minutes

15 - 30 minutes

Peak Action

Minimal or no peak

3 - 9 hours

1 - 3 hours

0.5 - 2.5 hours

Duration of Action

Up to 24 hours

Up to 24 hours

3 - 5 hours

3 - 5 hours

Injection Frequency

Once daily

Once or twice daily

Multiple times daily

Multiple times daily

Color of Solution






Refrigeration before opening; Room temperature after opening

Refrigeration before opening; Room temperature after opening

Refrigeration before opening; Room temperature after opening

Refrigeration before opening; Room temperature after opening

Common Brand Names

Lantus, Basaglar





Bottom Line

Understanding the characteristics and differences among various insulin formulations is crucial for effective diabetes management. Insulin glargine, insulin detemir, insulin aspart, and insulin lispro each have unique onset, peak action, duration, and injection frequency profiles, which can impact blood glucose control and treatment adherence.

Insulin glargine, known by its brand name Lantus, offers a long duration of action and is typically administered once daily, providing basal insulin coverage throughout the day and night. This stability in blood glucose levels can help individuals maintain consistent glycemic control.


Back to blog

Related Blogs

Leave a comment

Please note, comments need to be approved before they are published.