Metformin is an oral antidiabetic medication used primarily in the treatment of type 1 and type 2 diabetes, as well as polycystic ovarian syndrome. It acts to improve insulin sensitivity and lower glucose levels in the blood.
Metformin comes in 500 mg, 750 mg, 850 mg, or 1000 mg pills and is sold as the generic "metformin" and under the brand name Glucophage, among others. It is a prescription medication and can be found at most pharmacies and drug stores.
Metformin should only be used under a doctor's supervision and requires individualized dosing and regular medical appointments to check blood sugar levels and assess for the presence of any side effects.
What it's used for
Metformin is indicated for the treatment of:
- Type 2 diabetes, used alone or in combination with other oral diabetes medications;
- Type 1 diabetes, used along with insulin;
- Polycystic ovarian syndrome.
Metformin may also be used in the prevention of type 2 diabetes in people with prediabetes or overweight when diet and exercise are not enough to control blood sugar levels.
How it works
Metformin lowers levels of glucose in the blood by improving insulin sensitivity, reducing the production of glucose in the liver, and decreasing absorption of glucose in the gut.
Metformin has also been shown to have cardiovascular benefits, such as helping to reduce atherosclerotic plaques, which are accumulations of fatty substances in the arteries. It has also been shown to lower levels of total cholesterol, LDL, and triglycerides in the blood.
Does metformin cause weight loss?
Use of metformin is associated with weight maintenance and modest weight loss in clinical studies.
Metformin should not be used as a weight loss drug, however, unless indicated by your doctor, as it can cause unwanted side effects.
Recommended dosing
Metformin is taken by mouth, with a full glass of water, during or immediately following a meal.
Dosing instructions vary depending on the condition that is being treated, which include:
1. Type 2 diabetes
The recommended starting dose for adults with type 2 diabetes (who are not insulin dependent) is one 500 mg pill 2-3 times a day or one 850 mg pill once a day.
The dose can be increased as needed by a doctor based on blood sugar results.
Metformin can be used alone or in combination with other diabetes medications, such as sulfonylureas, to treat adults with type 2 diabetes.
2. Type 1 diabetes
The recommended starting dose for adults with type 1 diabetes (insulin dependent) is one 500 mg pill or one 850 mg pill 2-3 times a day, with insulin doses adjusted as needed by your doctor based on blood glucose levels.
3. Polycystic ovarian syndrome
The dose of metformin for the treatment of polycystic ovarian syndrome (PCOS) in adults is usually 1000 to 1500 mg per day, divided in 2 or 3 doses.
Treatment should be initiated at a low dose and increased gradually by your doctor until reaching the desired dose.
In some cases, a doctor may prescribe one 850 mg pill 2-3 times a day. For metformin in the form of 1000 mg pills, your doctor may recommend 1-2 pills daily.
4. Prediabetes
The dose of metformin for adults with prediabetes is 500 mg once a day, taken with breakfast, and can be increased by your doctor based on blood sugar levels and/or a hemoglobin A1c level.
Read about a prediabetes diet.
Side effects
The most common side effects of metformin are digestive issues like nausea, vomiting, diarrhea, abdominal pain, loss of appetite, changes in taste, and vitamin B12 deficiency.
Lactic acidosis can also occur with use of metformin, with symptoms like feeling cold, dizziness, weakness, muscle pain, vomiting, and irregular or slow heart beat. It is important to seek emergency medical attention if you experience any symptoms of lactic acidosis.
Can metformin cause impotence?
Metformin does not cause impotence, however uncontrolled diabetes can lead to erectile dysfunction.
Contraindications to use
Metformin should not be administered to children under the age of 10. It is also contraindicated in people with an allergy to metformin and patients with a current or past history of liver or kidney problems, uncontrolled diabetes, severe hypoglycemia, or diabetic ketoacidosis.
The use of metformin should be avoided in the setting of dehydration and serious infections. People who have recently suffered a heart attack should not take metformin. Metformin should not be used in patients undergoing treatment for heart disease or in those with poor circulation or respiratory difficulties.
Metformin should not be given to patients undergoing major elective surgery or having an exam with iodinated contrast. Heavy alcohol use is also a contraindication to the use of metformin.
Metformin should only be used in pregnancy and lactation if indicated by a doctor.