Insulin Glargine – What It Is and How to Use It

If you’ve been prescribed a once‑daily insulin, chances are you’re using insulin glargine. It’s a long‑acting insulin that mimics the body’s natural basal insulin, keeping blood sugar steady overnight and between meals. Unlike rapid‑acting shots that you take right before eating, glargine is meant to work in the background all day.

Understanding how it works, how to dose it correctly, and what to watch out for can make a big difference in your daily routine. Below you’ll find straight‑forward advice that cuts through the jargon and gets you the info you need to feel confident about your treatment.

How Insulin Glargine Works

Insulin glargine forms tiny, soluble crystals when injected under the skin. These crystals dissolve slowly, releasing a steady amount of insulin over roughly 24 hours. Because the release is gradual, you usually only need one injection a day, often at the same time each evening.

What this means for you is a more stable glucose curve. You won’t see the sharp peaks and drops that can happen with short‑acting insulins if you miss a meal or snack. It also reduces the risk of low blood sugar while you’re sleeping, which is a common worry for many diabetics.

Keep in mind that glargine isn’t a cure—it simply fills in the basal insulin gap. You’ll still need fast‑acting insulin or other glucose‑lowering strategies for meals and corrections.

Tips for Safe Use and Storage

Start low, go slow. Your doctor will calculate a starting dose based on weight, current blood sugar, and other meds. Most people begin with 0.1–0.2 U/kg per day. Adjustments happen gradually, usually in 2–4 U steps, until you hit your target range.

Pick a consistent time. Take the shot at the same hour each day—usually bedtime works for many because it lines up with the overnight insulin need. If you need to switch times, talk to your provider first.

Don’t reuse needles. Even though the insulin itself can stay in the pen for up to 28 days after opening, the needle should be changed with every injection to avoid infection and keep dosing accurate.

Store it right. Keep the unopened vial or pen in the fridge (2‑8 °C). Once opened, you can leave it at room temperature for up to 28 days; don’t expose it to extreme heat or direct sunlight.

Watch for signs of low blood sugar. If you feel shaky, sweaty, or confused, check your glucose right away. If it’s below 70 mg/dL, treat with fast carbs and re‑check in 15 minutes.

Know the side effects. The most common issues are mild redness at the injection site and occasional low blood sugar if the dose is too high. Rarely, people develop allergic reactions—look for swelling, itching, or rash and call your doctor.

Finally, keep a log of your doses, blood sugar readings, and any symptoms. This record helps you and your healthcare team spot patterns and fine‑tune the plan.

Managing diabetes is a team effort, and insulin glargine is a reliable teammate when you use it correctly. Follow these practical steps, stay in touch with your provider, and you’ll feel more in control of your glucose every day.