Can you use a CGM without diabetes? A guide for Australians

Yes. You can wear a continuous glucose monitor (CGM) in Australia without diabetes, and you do not need a prescription to order one through Vively. A CGM shows how your glucose changes through the day and night, so you can see how your own meals, sleep, exercise and stress affect you. You get 14 days of feedback from your own body, which you can use to choose changes that suit you.

Not sure whether a CGM is for you? Tick the statements that sound like you.

If one or more of these sounds like you, a 14-day CGM program is an easy way to start. If you have symptoms, or want to know whether you have diabetes, see your GP for a blood test first. A CGM is not a diagnostic test.

What is a CGM and how does it work?

A CGM is a small, round sensor you wear on the back of your upper arm. You put it on at home with an applicator, and a thin, flexible filament sits just under your skin. Most people feel a quick pinch or nothing at all.

The sensor measures glucose in the fluid between your cells every few minutes and sends the readings to an app on your phone. It is water resistant, so you can shower and exercise with it on. Each sensor lasts up to 14 days. Our guide on where to put a CGM explains how to apply it.

For more on how CGMs work and the options sold in Australia, see our guide to continuous glucose monitors.

What can a CGM show you if you don't have diabetes?

People respond differently to the same food. In a 2015 study of 800 adults, Zeevi and colleagues found that glucose responses to identical meals varied widely from person to person. A CGM shows you your own responses, so you can see:

• which of your usual meals cause a big rise in glucose, and which keep it steadier
• whether small changes make a difference to your readings, such as adding protein to breakfast, eating your vegetables first or walking for 10 minutes after dinner
• how a short night's sleep or a stressful day shows up in your glucose the next morning
• how exercise affects your glucose during a session and in the hours after it
• what your glucose does overnight while you sleep

You see the result within minutes of eating, so it is easier to link a choice to its effect and decide which changes are worth keeping.

What is a normal glucose level without diabetes?

Glucose rises after you eat carbohydrates, then comes back down as your body uses or stores it. That is normal. Diabetes Australia says glucose in people without diabetes generally stays between 4.0 and 7.8 mmol/L.

The Vively app shows your readings against a 4 to 6 mmol/L range. That is a tighter band than the apps that come with most sensors, which use 3.9 to 10.0 mmol/L, the target range for people with diabetes. A tighter range makes it easier to see which meals and habits move your glucose most. Going above it after a meal now and then is common, even in healthy adults, and is not a sign of disease on its own. Our guide to blood sugar after eating explains what to expect.

How to get the most out of 14 days

A simple plan works well:

• Days 1 to 3: eat and live as usual, and log your meals, sleep and exercise. This gives you a baseline.
• Days 4 to 10: test one change at a time. Swap your usual breakfast, add protein to a meal or take a short walk after dinner, then compare the readings with your baseline.
• Days 11 to 14: repeat the changes that made a difference, to check the effect holds, and decide which ones you want to keep.

Look for patterns that repeat over several days, and pay attention to how full and energetic you feel as well as the numbers. A lower reading does not always mean a better meal, so keep eating a variety of foods, including carbohydrates such as fruit, wholegrains and legumes. Our glucose spikes page shows how common foods affected Vively members.

How Vively's CGM program helps

You can buy a sensor on its own, but the app that comes with it is built for diabetes care. Vively's CGM program is built for people without diabetes who want to understand their glucose and what to change. Each pack includes the Sibionics GS3 sensor plus the Vively app and program:

• A range that suits you. The app shows your readings against 4 to 6 mmol/L.
• Your meals, sleep and exercise in one place. Log them in the app and see how each one lines up with your glucose.
• Your blood test results next to your glucose. Results from a Baseline Health Check sit in the same app.
• Dietitian coaching. It is available when you upgrade to the $99 a month Vively membership.
• No prescription needed. You can order online.

One sensor costs $199, two cost $358 and four cost $499. Our CGM cost guide compares this with buying a sensor on its own.

What a CGM can't tell you

A CGM is a measurement tool. It cannot diagnose diabetes, prediabetes or insulin resistance, and it does not measure insulin or hormones. If you have symptoms, or want to know whether you have diabetes, your GP can arrange blood tests such as a fasting glucose test, HbA1c or fasting insulin.

Sensor readings run around 6 to 12 minutes behind blood glucose, and lying on the sensor overnight can cause a false low reading. If a reading does not match how you feel, check it with a finger prick and follow the device instructions. Our common CGM mistakes guide has troubleshooting tips.

If you have a history of disordered eating or health anxiety, talk to your GP before you start, because tracking numbers closely may not suit you.

For a detailed look at the research, read our Medical Director's evidence review, CGM in people without diabetes: what the research shows.

Can I get a subsidised CGM without diabetes?

No. NDSS subsidies are for people with type 1 diabetes and some other eligible groups. Everyone else, including people without diabetes, pays privately. Our CGM cost guide lists current prices.

Frequently asked questions

Is a CGM worth it if I don't have diabetes?

It is worth it if you want to understand how your meals and habits affect your glucose, and you plan to use what you learn. Fourteen days of readings is enough to test several meals and routines. If you want a diagnosis or have symptoms, start with your GP and a blood test.

Do I need a prescription for a CGM?

No. You can buy a CGM privately in Australia without a prescription, and you do not need a doctor's referral to order through Vively.

Does a CGM hurt?

Most people feel a quick pinch or nothing at all when the applicator puts the filament in. Once it is on, most people forget it is there.

Should I stop eating foods that raise my glucose?

No. A rise after carbohydrate food is normal. Look at the whole meal and how often a pattern repeats. Small changes, such as a smaller portion or adding protein, are easier to keep than cutting foods out. If you find yourself avoiding lots of foods, talk to a dietitian.

Can a normal CGM graph rule out insulin resistance?

No. A CGM measures glucose, not insulin, and glucose can stay in a normal range while insulin rises. Ask your GP about a fasting insulin test if you are concerned.

Sources

1. Zeevi and colleagues: personalised nutrition by prediction of glycaemic responses, Cell, 2015.
2. Diabetes Australia: blood glucose range.
3. Battelino and colleagues: clinical targets for CGM data interpretation, Diabetes Care, 2019.
4. Shah and colleagues: CGM profiles in healthy participants, 2019.
5. NDSS: continuous glucose monitoring products.