A doctor’s perspective for Australians over 30
If you are over 30, you may have been told your blood sugar is “a bit high,” that you have insulin resistance, prediabetes, or type 2 diabetes. Perhaps you feel exhausted after meals, struggle with weight around your waist, or lie awake worrying about complications like kidney damage, heart attack, blindness, or amputation. You may also fear that diabetes means daily needles and expensive medicines for life.
Here is what I tell my patients in clinic: the earlier you act, the better your future can be. And when it comes to first-line treatment, one medicine stands above the rest—metformin. It has been used for more than 60 years, is recommended by Australian diabetes guidelines, and is one of the safest, most affordable tools we have. If you have type 2 diabetes or are heading that way, metformin could help you protect your energy, your organs, and your quality of life.
Metformin is not insulin, and it does not simply force your pancreas to pump out more insulin. Instead, it works through several useful mechanisms that fit the way your body naturally handles sugar.
Because metformin does not force your insulin levels too high, it rarely causes low blood sugar (hypoglycaemia) when used alone. That means fewer shaky, sweaty episodes and fewer cravings caused by sugar crashes.
Many patients ask whether food affects how metformin is absorbed. The answer is reassuring: food has only a modest effect on metformin absorption. It may slightly delay how quickly the drug enters your bloodstream and can lower the peak level, but it does not cancel out its glucose-lowering benefit. Taking metformin with or immediately after food is strongly recommended because it greatly reduces common stomach upset such as nausea, bloating, and diarrhoea. If you use extended-release metformin, taking it once with your evening meal is a simple routine that many Australians find easy to maintain.
| Topic | Key facts |
|---|---|
| Drug class | Biguanide |
| TGA approval status | Fully registered by the Therapeutic Goods Administration for type 2 diabetes mellitus; available in immediate-release and extended-release tablets |
| PBS listing | Listed on the Pharmaceutical Benefits Scheme, making it heavily subsidised for eligible Australians |
| Common starting dose | 500 mg once or twice daily with food, gradually increased as directed by your GP; extended-release often 500 mg–2 g once daily with evening meal |
| Common side effects | Nausea, diarrhoea, metallic taste, abdominal bloating—usually temporary and reduced by slow dose increases |
| Serious rare side effect | Lactic acidosis—very rare but seek urgent medical help if you have severe muscle pain, trouble breathing, extreme tiredness, or feel cold with a slow heartbeat |
If you are over 50, you may worry about osteoporosis and fractures. Unlike some diabetes medicines, metformin does not weaken bones or increase fracture risk. Large observational studies suggest it may actually have a neutral or slightly protective effect on bone health, probably because better insulin sensitivity and fewer low-sugar falls help protect your skeleton. Many GPs consider metformin a bone-friendly diabetes medicine. Of course, you still need calcium, vitamin D, and weight-bearing exercise for bone strength.
A skin rash from metformin is uncommon, but it can occasionally occur as a sign of allergy or sensitivity. Symptoms may include hives, redness, itching, or peeling skin. If you notice any rash after starting metformin, stop the medicine and contact your doctor immediately. Often switching brands or changing to an extended-release form solves the problem because different inactive fillers may be responsible. Serious skin reactions are very rare, but all rashes deserve medical review.
I always advise honesty here. Moderate alcohol intake—occasionally, with food, and within Australian guidelines—may be acceptable for some people with stable diabetes. However, binge drinking or regular heavy alcohol use is dangerous with metformin. Alcohol can increase the risk of lactic acidosis, a rare but serious condition, especially if you have liver disease, kidney impairment, or heart failure. The safest approach is to keep alcohol minimal, never drink on an empty stomach, and discuss your habits openly with your GP.
This is one of the most exciting areas of metformin research. Metformin is not approved or marketed as a cancer prevention drug, and you should not take it solely for that reason. However, many large observational studies in people with type 2 diabetes have found that those taking metformin tend to have lower rates of certain cancers—including colorectal, pancreatic, liver, and breast cancer—compared with people not taking metformin. Researchers believe metformin’s ability to lower insulin levels and activate AMPK may reduce abnormal cell growth. Clinical trials are ongoing, but the existing evidence is reassuring and may be an extra long-term benefit for people who need metformin for diabetes anyway.
Metformin is a cornerstone of Australian diabetes care. The Royal Australian College of General Practitioners and Diabetes Australia recommend metformin as first-line medicine for type 2 diabetes when lifestyle measures are not enough, unless there is a medical reason not to use it. It is available on the Pharmaceutical Benefits Scheme (PBS), which means eligible patients pay a standard PBS co-payment rather than the full private price. The PBS co-payment is around $31.60 for general patients and $7.70 for concession card holders, though prices can change and some pharmacies may charge less. This makes metformin one of the most affordable diabetes medicines in Australia.
Metformin is fully approved by the Therapeutic Goods Administration (TGA) for the treatment of type 2 diabetes mellitus in adults and, where appropriate, children over 10 years. It is available as immediate-release and extended-release products under several Australian brand names, including Diabex, Diaformin, Glucomed, and generic metformin. Because it is a Schedule 4 prescription medicine, you need a doctor’s script to buy it from an Australian pharmacy.
| Worry | Fact |
|---|---|
| “Will metformin ruin my bones?” | No. It does not increase fracture risk and may be bone-neutral or protective. |
| “Can I never drink alcohol again?” | Moderate alcohol with food may be okay for many, but avoid binge drinking and discuss with your GP. |
| “Will I get a rash?” | Rash is uncommon; if it happens, switch brand or form after medical review. |
| “Is metformin expensive in Australia?” | No. PBS-subsidised, often around $31.60 or less for general patients and $7.70 for concession card holders. |
| “Does metformin cause cancer?” | No. Observational evidence suggests it may lower rates of certain cancers in people with diabetes. |
Imagine three months from now: your blood glucose readings are lower, your HbA1c has improved, your energy is more stable through the day, and you are taking a medicine that costs less than a café lunch. You are not chained to daily needles or an expensive regimen. You are using a drug that has protected millions of people from the worst complications of type 2 diabetes.
Metformin is not a magic cure, and it works best alongside healthy eating, regular walking, weight management, and regular check-ups. But for many Australians over 30, it is the foundation that makes those lifestyle efforts actually show up in your blood test results.
Here is how to take the next step:
If you are over 30 and living with type 2 diabetes or prediabetes, don’t wait for symptoms to worsen. Ask your GP whether metformin is right for you. It may be the safest, cheapest, and most effective decision you make for your future health.
