Attention: If You Are Over 30 and Living with Type 2 Diabetes, This Should Be on Your Radar

As a doctor practising in Australia, I meet people in their 30s, 40s, 50s and beyond who feel exhausted, thirsty, frustrated by weight gain, and secretly terrified of needles. Many have been told their blood sugar is “a bit high” — but they do not realise that the first medicine recommended in Australian and international guidelines is also one of the most effective, safest and best-value options available: metformin.

Metformin has been used for more than 60 years, yet it still stands at the top of type 2 diabetes treatment. It helps lower blood glucose, does not cause significant weight gain, rarely causes hypoglycaemia on its own, and is available on the Pharmaceutical Benefits Scheme (PBS). If you are newly diagnosed, or if you have been struggling with diabetes for years, this review will help you understand why metformin matters, how it is used safely in Australia, and what questions to ask your own doctor.

Interest: Why Metformin Remains the First Choice

Metformin works mainly by reducing the amount of glucose your liver releases, especially overnight, and by improving your body’s response to insulin. This means it targets one of the core problems in type 2 diabetes: insulin resistance. It does not push the pancreas to make extra insulin, which is why hypoglycaemia is uncommon.

Australian guidelines, including those used by the Royal Australian College of General Practitioners (RACGP) and the Australian Diabetes Society, recommend metformin as first-line treatment for most adults with type 2 diabetes, alongside healthy eating and regular physical activity.

How to apply for PBS authority for metformin?

In Australia, plain metformin tablets are PBS-listed as a Restricted Benefit for the treatment of type 2 diabetes mellitus. For a standard PBS prescription, you generally do not need to telephone Medicare or complete a written authority form. Your GP simply selects the PBS metformin item and includes the indication “type 2 diabetes” on the prescription.

Some fixed-dose combination products — for example, metformin combined with another glucose-lowering medicine — may be listed as Streamlined Authority Required. In those cases, the prescriber uses a streamlined authority code in their prescribing software. This is usually quick and does not require a phone call. Your doctor or pharmacist can confirm the current PBS listing for your particular metformin product.

The take-home message: accessing metformin in Australia is straightforward. If you have type 2 diabetes, ask your GP whether metformin is right for you. In most cases, your prescription can be filled at any Australian pharmacy without burdensome approval steps.

Desire: Safety, Monitoring and Real Answers to Your Fears

Many people worry about side effects, kidney health, vitamin levels and whether they will need extra medicines. Here are the key facts every Australian adult should know.

eGFR range for safe metformin use

Your kidneys clear metformin from the body, so your doctor will check your kidney function with a blood test called eGFR (estimated glomerular filtration rate). The table below summarises how Australian prescribers think about safe metformin use.

This table is a guide only. Your GP may use a slightly different approach based on your overall health, age, muscle mass and other conditions. The key point: when kidney function is normal or only mildly reduced, metformin is very safe.

What is the link between metformin and vitamin B12?

Metformin can reduce the absorption of vitamin B12 in the gut, especially with long-term use. Low B12 may cause fatigue, pins and needles, numbness, balance problems, memory difficulties or anaemia. These symptoms can easily be mistaken for diabetes-related nerve damage or ageing.

In Australia, doctors are encouraged to check vitamin B12 levels before starting metformin and then at least once a year, particularly if you have been taking metformin for several years or develop new neuropathy symptoms. If your B12 is low, treatment with oral or injectable B12 is simple and effective. This does not usually mean you need to stop metformin.

Does metformin cause lactic acidosis?

Lactic acidosis is a rare but serious condition. With metformin, it occurs mainly in people with severely reduced kidney function, liver disease, severe infection, dehydration, recent major surgery, or after drinking large amounts of alcohol. In people with normal kidney function, the risk is estimated at around 3–10 cases per 100,000 patient-years — extremely low.

To reduce risk, your doctor will check your kidney function, advise you to pause metformin during severe illness or before certain procedures, and review your dose. When used correctly, metformin is one of the safest diabetes medicines available.

How to recognise hypoglycaemia on metformin?

Metformin alone rarely causes hypoglycaemia because it does not stimulate excessive insulin release. However, hypoglycaemia can occur if you also take insulin, sulfonylureas, skip meals, drink alcohol, exercise intensely, or have kidney impairment. Being able to recognise low blood sugar is still important.

If you suspect hypoglycaemia, check your blood glucose level if possible. If it is below 4.0 mmol/L, treat with 15 grams of fast-acting carbohydrate — for example, 6–7 jelly beans, half a can of regular soft drink, or glucose gel. Recheck after 15 minutes. If you take metformin alone and develop low blood sugar, your doctor will investigate other causes.

When is it appropriate to add a second agent to metformin?

Metformin is excellent, but type 2 diabetes can change over time. Adding a second medicine is not a failure — it is a normal part of good management. Your doctor will usually consider adding a second agent when your HbA1c remains above your individual target despite 3–6 months of lifestyle changes and maximum tolerated metformin.

The right choice depends on your heart health, kidney function, weight, risk of hypoglycaemia, preferences and PBS eligibility. Your GP will help you weigh the options — but the foundation usually remains metformin.

Can metformin be stopped if blood sugar normalises?

This is one of the most common questions I hear. If your blood sugar normalises while taking metformin, it usually means the medicine is working — not that the diabetes has gone away. Stopping metformin often leads to rising glucose levels again, even if you feel well. High blood sugar can damage blood vessels, nerves, kidneys and eyes over time without causing immediate symptoms.

Some people can achieve true diabetes remission through significant weight loss, especially in the first few years after diagnosis. In that situation, a doctor may carefully reduce or stop medicines under supervision. But this should never be done alone. If you think you might be in remission, ask your GP for a structured review, including repeat HbA1c testing and a clear follow-up plan.

Are there any new metformin formulations in development?

Researchers continue to explore new ways to use metformin. Delayed-release metformin formulations that target the lower bowel may allow lower doses with fewer side effects and less systemic absorption — potentially useful for people who experience stomach upset or kidney concerns. Fixed-dose combination tablets that include metformin plus an SGLT2 inhibitor or DPP-4 inhibitor are already available and help reduce pill burden. Newer combinations and extended-release options continue to be developed.

In Australia, the immediate-release and extended-release forms remain the most widely prescribed. If you struggle with nausea, diarrhoea or abdominal discomfort, ask your doctor about the extended-release form or a slow dose-titration schedule before giving up on metformin.