How much metformin to lose weight?

Though metformin, which is sold under the brand names Glucophage and Glucophage XR, is primarily used as a diabetic medication, doctors and overweight patients have discovered that it can also be used to cause weight loss.


Metformin lowers blood insulin levels and helps patients control blood glucose levels. This makes it beneficial for people with Type II diabetes, particularly overweight Type II diabetes sufferers, but it also benefits someone who is simply overweight. Metformin has been approved by the U.S. Food and Drug Administration (FDA), but only for use as a diabetic medication, not weight loss. Metformin is also known to reduce acne, restore the menstrual cycle in women with polycystic ovary syndrome (PCOS), improve the chance of pregnancy in women with PCOS and reduce the risk of miscarriage.

What It Does

Metformin lowers blood insulin levels by decreasing absorption of carbohydrates through the intestines. It reduces the production of glucose in the liver and increases the sensitivity of muscle cells to insulin.

For Weight Loss

Eating causes your blood glucose to rise. This increase causes your body to make more insulin. Insulin tells your brain that you're hungry, causing you to eat more. Insulin also tells your liver to manufacture fat. If you can keep your insulin levels from increasing, you can reduce hunger pains and fat creation and storage. Reducing insulin is metformin's primary function.

When Metformin Doesn't Work

If you eat foods that rapidly increase your blood glucose level, metformin won't be effective for weight loss. The rapid increase causes the body to produce insulin before metformin can have any effect. Also, not all tests consistently display weight loss using metformin. But all tests confirm that this medication is at least effective in preventing further weight gain.


Metformin comes in 500 mg, 850 mg and 1,000 mg tablets. The usual dose is 850 to 1,000 mg twice daily. The maximum safe dose is 850 mg three times daily. Glucophage XR is an extended-release tablet that will allow the patient to take only a single pill each day. Patients usually start with a low dose to see how the drug affects them. If a greater decrease in insulin is needed, a doctor will gradually increase the dosage.

Consult Your Doctor

Talk to your doctor about whether you should use metformin for weight loss. The drug can cause nausea and/or diarrhoea. This could account for some of the weight loss and it may not be something you want to endure. If you opt to try metformin, you should have a metabolic assessment before taking the medication and be rechecked once a year.

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