Metformin: The TGA-Approved Foundation of Modern Diabetes Care — An Australian Doctor’s Review

Disclaimer: This article is for educational and informational purposes only and reflects a doctor’s perspective. It is not individual medical advice. Always consult your GP, endocrinologist or credentialled diabetes educator before starting, changing or stopping any medication.

Attention: The Hidden Burden of High Blood Sugar in Australia

If you are over 30 and have been told your blood glucose is “a little high”, or you already live with type 2 diabetes, you probably recognise the daily struggles: constant tiredness, brain fog, stubborn weight around the middle, frequent trips to the toilet, and a nagging fear about your heart, kidneys, eyes and nerves. In Australia, more than 1.3 million people live with diabetes, and many more have prediabetes without knowing it.

The frustration is real. You may feel like you are doing everything “right” but the numbers don’t move. You may worry about needing injections, losing your eyesight, or ending up on dialysis. You may also feel overwhelmed by the cost of medicines and complicated treatment plans.

Here is what I tell my patients: one of the most powerful, safest and most affordable tools we have is not new, it is not expensive, and it has decades of evidence behind it. It is called metformin.

Interest: What Exactly Is Metformin?

Metformin is a medicine from the biguanide class. Its active ingredient is metformin hydrochloride, and its chemical name is 1,1-dimethylbiguanide hydrochloride. This may sound complicated, but the way it works is reassuringly simple: metformin lowers the amount of glucose your liver releases into the blood and helps your muscles and fat cells respond better to insulin.

Unlike some diabetes medicines, metformin does not push the pancreas to make more insulin. That means it has a very low risk of causing dangerous low blood sugar when used alone. This is a major reason doctors in Australia and around the world choose metformin as first-line treatment for type 2 diabetes.

Desire: Why Australian Adults Over 30 Should Feel Confident About Metformin

Does Metformin Have Cardiovascular Benefits?

Yes. This is one of the most important reasons doctors like metformin. The landmark UKPDS study showed that in overweight people with type 2 diabetes, metformin reduced the risk of heart attack by around 39%, diabetes-related death by 42%, and all-cause death by 36% over the study period. These benefits appear to persist for years — a concept known as the “legacy effect”.

While newer medicines such as SGLT2 inhibitors and GLP-1 receptor agonists also have strong cardiovascular protection, metformin remains the foundation. It improves blood glucose, supports modest weight loss, reduces inflammation, and improves lipid profiles. For many patients, this means a lower chance of heart attack, stroke and premature death.

Metformin and Mental Health: Does It Help Depression?

This is a question I hear more often than you might expect. Depression is common in people with type 2 diabetes — the two conditions feed each other through chronic inflammation, insulin resistance, and the exhaustion of managing a long-term illness.

Emerging research suggests metformin may have a positive effect on mood in some people. Because it improves insulin sensitivity and may reduce inflammation in the brain, some studies have found that metformin users with diabetes report improvement in depressive symptoms compared with those not using metformin. It is not an antidepressant and should not replace mental health treatment, but for people whose low mood is linked to metabolic dysfunction, metformin can be a useful additional piece of the puzzle.

Metformin and Fasting: Guidance for Ramadan

For Muslim Australians who observe Ramadan, fasting from dawn to sunset can raise concerns about diabetes medicines. The good news is that metformin is generally considered one of the safer options during Ramadan because it rarely causes hypoglycaemia when used alone.

However, the timing of doses must change. A practical approach, endorsed by many diabetes experts, is to take the larger dose of metformin with the evening meal after breaking the fast (iftar), and a smaller dose with the pre-dawn meal (suhoor). This helps reduce stomach upset and maintains glucose control during the fasting hours.

Special caution applies if you have kidney disease, liver problems, recent illness, or take other glucose-lowering medicines such as insulin or sulfonylureas. In those cases, a pre-Ramadan assessment is essential.

Metformin in Pregnancy: TGA Pregnancy Category C Explained

Australian patients often ask about pregnancy safety. The Therapeutic Goods Administration (TGA) classifies metformin as Pregnancy Category C. This sounds alarming, but it does not mean the medicine is proven to cause birth defects. Category C means that there is limited human data, and a harmful effect on the fetus is possible but not confirmed, and the benefits may justify use in certain circumstances.

In clinical practice, metformin is used under specialist guidance during pregnancy for some women with type 2 diabetes, polycystic ovary syndrome (PCOS) and gestational diabetes. Insulin remains first-line for many pregnant women, but metformin is increasingly used when the benefits outweigh the risks. If you are planning a pregnancy or are already pregnant, never stop or start metformin without advice from your obstetrician or endocrinologist.

Smart Combinations: Empagliflozin and Sitagliptin

Sometimes one medicine is not enough. Metformin combines very well with modern diabetes drugs, allowing lower doses and complementary effects.

In Australia, fixed-dose combinations such as Jardiamet (empagliflozin/metformin) and Janumet (sitagliptin/metformin) are available and PBS-listed for eligible patients. These reduce pill burden and improve adherence.

Can Metformin Cause Itching?

Metformin is generally well tolerated, but like any medicine, it can cause side effects. Itching is uncommon but possible. It may occur as part of a mild skin rash or, rarely, as an allergic reaction. If you develop itching along with hives, swelling of the lips or tongue, or difficulty breathing, stop the medicine and seek urgent medical attention immediately.

It is also worth remembering that itching in diabetes can be caused by dry skin, poor circulation, or other medications. If you notice persistent itching after starting metformin, do not simply put up with it — see your GP. Most side effects of metformin are gastrointestinal, such as nausea, diarrhoea, or abdominal discomfort, and these usually settle after a few weeks when the dose is increased slowly.

Key Facts at a Glance

Action: Take Control of Your Metabolic Health Today

If you are over 30, tired of feeling unwell, worried about heart disease, or struggling to manage your blood glucose, metformin may be a safe, effective and affordable option for you. It is not a fad — it is a cornerstone of diabetes care, backed by more than 60 years of clinical experience and listed on the Pharmaceutical Benefits Scheme (PBS) in Australia.

You do not need to struggle alone. Book an appointment with your GP and ask these three questions:

• “Could metformin be right for me?”
• “What is my current HbA1c and what should my target be?”
• “How can I combine metformin with diet and exercise for the best result?”

If metformin is appropriate, your doctor can issue a prescription, and you can purchase it from any registered Australian pharmacy. The investment is small, but the potential benefit — a healthier heart, steadier energy, better mood, and protection against diabetes complications — is enormous.

Doctor’s final word: Metformin is not a miracle cure, but it is one of the closest things we have to a proven foundation for managing type 2 diabetes. When used correctly, it is safe, inexpensive, and genuinely life-changing for many Australians. Speak with your GP today and take the first step toward a longer, healthier life.