Insulin and technology for type 1 diabetes

How basal and mealtime insulin work, using insulin pens, injection sites and storage, and how glucose sensors (CGM), insulin pumps and automated insulin delivery can make daily life easier.

7 min read · last reviewed October 3, 2026

Insulin is the heart of type 1 diabetes care. It replaces the insulin your pancreas can no longer make. Learning to use it can feel scary at first, but within a few weeks most people find it becomes part of their routine, like brushing their teeth. Technology such as glucose sensors and pumps can make it easier still.

This guide explains the basics. Your diabetes team will teach you the details and work out your doses with you.

Two jobs, two kinds of insulin

A healthy pancreas releases insulin in two ways: a small, steady amount all day and night, and extra bursts when you eat. Insulin treatment copies this.

• Basal (background) insulin is long-acting. It keeps your blood sugar steady between meals and overnight. It's usually taken once or twice a day, at about the same time.
• Bolus (mealtime) insulin is rapid-acting. You take it just before (or sometimes during) meals to cover the carbohydrates you eat. It's also used for correction doses to bring down a high reading.

Using both kinds is often called basal-bolus or multiple daily injections (MDI). Your team will teach you how to work out your mealtime doses, often using your insulin-to-carb ratio and correction factor.

Important: never skip your basal insulin, even if you're sick or not eating. Without it, ketones can build up quickly. See DKA: what to know.

Using an insulin pen

Most people use insulin pens. They're easy to carry, and the needles are very short and thin.

• Prime the pen before each dose (a small "air shot") to make sure insulin is flowing.
• Inject into the fatty layer under the skin, usually the belly, the front or side of the thighs, the back of the upper arms or the buttocks.
• Rotate your sites. Move each injection a finger-width or so from the last one, and switch areas in a regular pattern. Injecting into the same spot can cause lumpy skin (lipohypertrophy), which makes insulin work unpredictably.
• Use a new needle each time, and put used needles in a sharps container.
• Never share pens, even if you change the needle.

Something you can do today: Ask your educator to check your injection technique and your usual sites for any lumps.

Storing insulin

• Unopened insulin goes in the fridge (not the freezer).
• The pen or vial you're using can usually stay at room temperature for a set number of days. Check the package insert.
• Protect it from heat, direct sunlight and freezing. Never use insulin that has been frozen, or that looks cloudy or clumpy when it should be clear.
• Always keep a backup supply.

Continuous glucose monitors (CGM)

A CGM is a small sensor you wear on your arm or belly, usually for 1 to 2 weeks at a time. A tiny flexible filament under the skin measures your glucose every few minutes and sends readings to your phone, a reader or your pump.

CGMs show:

• your current glucose, plus arrows showing which way it's heading and how fast
• alarms for highs and lows, including overnight
• reports such as time in range, the percentage of the day your sugar is between 3.9 and 10.0 mmol/L (70 to 180 mg/dL). Many adults aim for more than 70% in range, with very little time low.

NICE recommends offering a CGM to all adults with type 1 diabetes, and the American Diabetes Association and Diabetes Canada also support their use. Ask your team which systems are available and covered for you. Keep a finger-prick meter as a backup, and use it if your symptoms don't match your sensor reading.

Something you can do this week: Ask your team, "Can I get a CGM, and how do I apply for coverage?"

Insulin pumps

An insulin pump is a small device that delivers rapid-acting insulin all day through a thin tube (or directly from a patch on the skin). It replaces your basal insulin injections with a steady trickle, and you press a button to give mealtime doses.

Pumps can make it easier to fine-tune insulin for different times of day, exercise and meals. They do take learning, and you need a backup plan:

• Because a pump only uses rapid-acting insulin, if insulin stops flowing (a kinked tube, a blocked site or an empty pump), ketones can rise within a few hours.
• Always carry backup insulin pens and supplies.
• If your blood sugar is high and won't come down after a correction, check for ketones and consider changing your infusion site.

Automated insulin delivery (closed loop)

Automated insulin delivery systems, also called hybrid closed loop or "artificial pancreas" systems, link a CGM to a pump. A computer program uses your glucose readings to adjust your insulin automatically, every few minutes. You still tell the system about meals.

Studies show these systems help many people spend more time in range and have fewer lows, especially overnight. NICE recommends them for many people with type 1 diabetes in the UK, and they're increasingly available in Canada and the U.S. They aren't magic, though. You still need to count carbs, change sites and sensors, and know what to do if the system stops working.

Choosing what's right for you

There's no single "best" setup. Some people prefer pens and a CGM. Others love their pump. What matters is that it's safe, fits your life, and you feel confident using it. Coverage and cost also matter, and your team can help you find programs that may help.

Questions to ask your care team

• How do I work out my mealtime and correction doses?
• Can you check my injection technique and sites?
• Which CGMs, pumps or automated systems would suit me? Are they covered?
• What's my backup plan if my pump or sensor fails?
• What should I do with my insulin when I'm sick or exercising?
• How do I store insulin when I travel?

This article is general information, not medical advice. Talk with your health care team about your own situation. In an emergency, call 9-1-1 or your local emergency number.

In an emergency, call 9-1-1 or your local emergency number.

General information, not medical advice. It does not replace your own care team. If you think you or someone else is having a medical emergency, call 9-1-1 or your local emergency number. If you are in crisis or thinking about suicide, call or text 9-8-8 (Canada and the US).

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