Why is Metformin Used for PCOS?

Before we get started on why Metformin is used for PCOS, here’s a quick refresher on Polycystic Ovary Syndrome (PCOS). This biochemical imbalance within the ovaries affects around 5 million US women, and of course, because it has to do with our chemistry, it can be different for every woman and tricky to figure out.  

With PCOS the ovaries are not producing the hormones estrogen and progesterone in the same patterns that will lead to ovulation and a normal menstrual cycle. The reason for this imbalance is an underlying insulin resistance that’s the root cause of PCOS. For a deeper dive into the biology of PCOS and Insulin Resistance you can see this post.  

The imbalance of hormones leads to higher amounts of androgenic, or male type, hormones than what is typically produced. All women have some DHEA, DHEAS and testosterone, but women with PCOS have a lot more. 

About 8% of women have PCOS, and it affects women of all races and ethnicities, though women with a family history are at higher risk.

This imbalance in hormones leads to:

• Irregular or absent menstrual periods from lack of ovulation
• Increased risk for uterine cancer
• More acne
• Excessive hair growth
• Difficulty losing weight
• Dark patches of skin on the neck and in the armpits

So, to sum up, with PCOS women have an underlying insulin resistance that leads to an imbalance of hormones. They have more androgenic hormones and they don’t have the typical pattern of estrogen and progesterone, so they don’t ovulate regularly, leading to irregular periods, heavy bleeding, and infertility.

Insulin Resistance

With insulin resistance, the normal way that insulin uses a key to open up the door on cell’s wall to allow it to take in glucose from our blood stream is altered. Think of it this way, glucose and insulin are friends who travel through our blood stream together holding hands. Insulin’s job is to be the key that unlocks the door at the cell wall. When there is an insulin resistance, the key gets stuck and doesn’t work as well. The glucose is there, the cell is hungry for the fuel, but the cell wall door is shut or resistant to opening. This leads to people feeling hungry all the time and the pancreas responding by making even more insulin. 

Metformin Therapy

Metformin was originally developed and typically is prescribed to treat Type 2 Diabetes, which shares characteristics with PCOS in that it involves insulin resistance and how sugars are metabolized and utilized by the cells in the body. It is known as an “insulin sensitizer” which means that it helps our body’s insulin be much more efficient in unlocking the door to transport glucose out of the blood and into the cells. It also has the effect of lowering insulin levels and all of that helps women have a normal menstrual cycle. 

Studies have shown that PCOS and obesity are interrelated; weight gain increases the chances of PCOS and PCOS results in weight gain and obesity. For more on this, see my blog post on Managing Your Weight with PCOS. Metformin also assists in weight loss, which helps increase the likelihood that a woman will ovulate and have a normal menstrual cycle. Some women find that using Metformin helps them conceive and get pregnant. 

Many fertility clinics use metformin in conjunction with clomid or Letrozole to improve the chances of conception in women with PCOS.

A Wonder Drug?

Aside from treating PCOS, researchers are reporting possibilities for metformin in other areas of health such as osteoarthritis, Alzheimer’s, inflammation, and even slowing down aging.

Side Effects and Warnings

The mild side effects of metformin include:

• diarrhea 
• cramping 
• bloating

Most of these side effects improve after 2 weeks. Talk to your health care provider about starting with 1 each day for a week, then increasing to 2 per day for a week or 2 before trying 3 per day.   

This medication should be used with caution in people with kidney disease.

Metformin and a Low Carb Diet

For anyone taking Metformin to reduce blood sugar, it helps to also reduce the amount of sugars and glucose we take in. Metformin is not like a free pass that allows us to eat all the donuts, candy, cookies, brownies, chips and other sugars we want. It’s best to think about substituting more vegetables, beans, and whole grains into our diets so that Metformin can work more efficiently. You can read more about 20 Practical Ways to Limit Carbs in my blog here.