Metformin and PCOS: What to Know

What You Need To Know About Taking Metformin If You Have PCOS


If you have Polycystic Ovary Syndrome (PCOS) and have been prescribed metformin, chances are you have a lot of questions and concerns about taking this medication. The majority of women with PCOS have high insulin levels which cause weight gain, cravings, and even dark patches on your skin. Over time, exposure to high insulin levels can make you insulin resistant or turn into type 2 diabetes. Metformin works to lower your insulin and reduce your risk for diabetes.

This article will show you what you need to know about taking metformin if you have PCOS.

How Does Metformin Work?

Metformin is one of the oldest and most studied drugs available in the United States. Other names for metformin include Glucophage, Glucophage XR, glumetza, and fortamet. Although it’s not labeled for use in women with PCOS, metformin is one of the most common medications used to manage the condition. Metformin has been studied in girls as young as 8 years of age, with some researchers recommending it to prevent the onset of PCOS. Metformin works as an insulin-sensitizer to reduce your production of glucose. Metformin lowers blood glucose and insulin levels in three ways:

1. It suppresses the liver's production of glucose.

2. It increases the sensitivity of your liver, muscle, fat, and cells to the insulin your body makes.

3. It decreases the absorption of carbohydrates you consume.

The average dose of metformin for women with PCOS is 1,500 mg to 2,000 mg daily.

Health Benefits of Metformin

Besides lowering your glucose and insulin levels, metformin may provide other health benefits to women with PCOS. Metformin can enhance ovulation and regulate menstrual cycles. This means if you are sexually active, you should use birth control to prevent pregnancy, even if you haven’t been getting your period regularly.

Metformin may even improve cholesterol and hirsutism symptoms like acne and excess hair growth. Metformin may assist with weight loss when accompanied by a healthy diet and exercise but is not a weight loss drug. Taking metformin while pregnant may reduce the risk of gestational diabetes and should be discussed with your physician.

What About the Side Effects?

Overall, most people can tolerate metformin just fine. The most common side effects experienced when you first start taking it are GI related and may include nausea, gas, bloating, abdominal discomfort and diarrhea. Some people find that the extended-release version of metformin is gentler on the digestive system and better tolerated.

Metformin should be taken with food to minimize side effects. Slowly increasing the dose of metformin over several weeks is recommended for best results. Eating sugary and processed foods can worsen the digestive side effects of metformin and should be avoided. You may find working with a registered dietitian nutritionist who specializes in PCOS helpful to create a meal plan that works best for your unique needs.

Metformin can affect the absorption of vitamin B12. Long-term use and high doses of metformin increase the likelihood of a vitamin B12 deficiency.  A lack of vitamin B12 can cause mood changes, memory loss and can cause permanent damage to the brain and nervous system. You should supplement your diet with vitamin B12 and have your levels checked annually. Optimal ranges of vitamin B12 should be >450 pg/mL. Elevated serum homocysteine and urinary methylmalonic acid (MMA) levels, the gold standard in assessing B12, also indicate a B12 deficiency.

Lactic acidosis is a rare side effect of metformin. Drinking alcohol while on metformin is not recommended.

Are There Natural Alternatives to Metformin?

There isn’t a substitute for metformin but for those individuals who can’t tolerate it or don’t want to take a prescribed medication, there are other ways to improve insulin sensitivity if you have PCOS-without the side effects. The most important are following a healthy diet and engaging in regular physical activity. N-acetyl cysteine is an antioxidant that was shown in one randomized controlled trial to work as well as metformin for reducing insulin and cholesterol in women with PCOS. Myo-inositol was found to restore ovulation resulting in more pregnancies than metformin. Myo-inositol has also been shown to improve insulin and other metabolic aspects of PCOS.


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