Metformin in Australia: A Doctor’s Review of the Affordable, Time-Tested Medicine for Type 2 Diabetes and Metabolic Health

By an Australian general practitioner

Attention: The Hidden Worry Behind High Blood Sugar, PCOS and Metabolic Health

If you are over 30 and have been told your blood sugar is “a bit high”, you have type 2 diabetes, or you struggle with polycystic ovary syndrome and unpredictable periods, you may already know the worry. You might be concerned about future heart problems, kidney damage, fatigue, weight gain, or medicines that cost a fortune. From my consulting room, one question comes up again and again: “Is there a medicine that works, is safe, and does not break the bank?”

For millions of Australians, the answer is metformin.

Interest: A Medicine with Centuries of History

Metformin’s story begins with French lilac (Galega officinalis), a plant used for centuries in traditional medicine for symptoms we now recognise as diabetes. In the early 20th century, scientists isolated compounds from this plant, and by the 1950s the French physician Jean Sterne developed metformin into a practical medicine. It was introduced into clinical practice in Europe and later became a cornerstone of diabetes care in Australia.

Today, metformin is on the World Health Organization’s list of essential medicines and is the recommended first-line tablet for type 2 diabetes in Australian guidelines. It works mainly by reducing the amount of glucose your liver releases into the bloodstream. It also helps your muscles and fat respond better to your own insulin. Unlike some diabetes medicines, metformin does not usually cause weight gain and does not tend to cause dangerous low blood sugar when used on its own.

In Australia, metformin is available as immediate-release and slow-release tablets. Common brands include Glucophage, Diaformin, Metex and Diabex, as well as generic versions. The slow-release form is often better tolerated by the stomach.

Desire: Why Metformin Remains a First-Choice Medicine

Affordable PBS Co-Payment: Kind to Your Wallet

In Australia, metformin is listed on the Pharmaceutical Benefits Scheme (PBS). This means the government subsidises the cost, making it one of the most affordable long-term medicines for type 2 diabetes, insulin resistance and PCOS. As of 2025, the standard PBS co-payment amounts are:

From a doctor’s point of view, this affordability matters. A medicine only works if you can keep taking it. Metformin’s low cost means you are more likely to stay on treatment for years, which is exactly what protects your heart, kidneys and blood vessels.

Metformin and Coronary Artery Disease: A Heart-Safe Choice

If you have coronary artery disease or are at high risk of heart attack, metformin is generally considered safe and beneficial. The landmark UK Prospective Diabetes Study found that metformin reduced diabetes-related complications and death in overweight people with type 2 diabetes. Metformin does not stimulate the heart or raise heart rate. By improving blood glucose, reducing insulin resistance and helping limit weight gain, metformin helps protect blood vessels over time.

Metformin can usually be continued in people with stable coronary artery disease, provided kidney function is acceptable. Always tell your doctor about any chest pain, breathlessness or heart failure symptoms so they can decide whether the dose is right for you.

Does Metformin Affect the Menstrual Cycle?

For women with PCOS or insulin resistance, metformin may improve menstrual regularity. PCOS is often driven by high insulin levels, which can disrupt ovarian hormone balance. Metformin lowers insulin levels, and as a result some women notice more predictable cycles and improved ovulation. It is not a contraceptive, and it does not work for every woman, but it can be a valuable option when periods are irregular or fertility is affected. If you are trying to conceive, discuss a full plan with your doctor.

Metformin and Empagliflozin: A Powerful Combination

Metformin is often combined with newer medicines such as empagliflozin. Empagliflozin belongs to the SGLT2 inhibitor class: it helps your kidneys remove excess glucose through urine. Metformin mainly reduces liver glucose output. Together they address high blood sugar from two different directions. This combination can improve HbA1c, support weight loss, reduce blood pressure, and provide heart and kidney protection.

In Australia, metformin and empagliflozin are available as separate tablets and as a combination tablet, making it easier to take fewer pills.

Metformin and Vitamin B12 Deficiency: Prevention Is Simple

One important but manageable issue with long-term metformin is vitamin B12 deficiency. Metformin can reduce absorption of vitamin B12 from the gut. Over years, this may lead to low B12 levels, which can cause fatigue, tingling or numbness in the hands and feet, memory problems, or a sore tongue.

Prevention is straightforward. Eat B12-rich foods such as meat, fish, eggs and dairy. Ask your doctor to test your vitamin B12 level before starting metformin and then every one to two years. If your level drops, oral B12 supplements or B12 injections can correct it quickly. Do not stop metformin because of this concern—monitoring and replacement are simple and effective.

What Are the Signs of Lactic Acidosis?

Lactic acidosis is a very rare but serious side effect of metformin. The risk is higher in people with severe kidney disease, liver disease, severe infection, dehydration, or heavy alcohol use. Know the warning signs:

These signs are rare when metformin is used correctly and kidney function is monitored. Do not ignore them, but do not fear the medicine—millions of people use it safely every day.

Is Metformin a Controlled Substance?

No. Metformin is not a controlled substance. In Australia it is a Schedule 4 prescription-only medicine. That means you need a doctor’s prescription, but it is not addictive, has no abuse potential, and does not cause a “high”. You will not develop cravings or withdrawal. This makes it a very safe long-term option.

Action: Talk to Your Doctor Today

If you are over 30 and have type 2 diabetes, prediabetes, PCOS, or metabolic concerns, talk to your GP about metformin. Bring your blood test results, and ask about your HbA1c, kidney function and vitamin B12 level. Your doctor can choose the right dose and formulation—often a low starting dose to reduce stomach upset, with a slow increase over several weeks.

You can take your script to any Australian pharmacy. Thanks to the PBS, metformin is one of the most affordable medicines you will ever take. If metformin is right for you, starting it could be a simple, powerful step toward protecting your heart, your blood sugar, your menstrual health and your future.

This article is general information and does not replace individual medical advice. Always consult your doctor before starting or changing any medicine.