PCOS and metformin

Metformin and PCOS: A treatment right for you?

September 21, 2021Hertility

Polycystic ovarian syndrome (PCOS) affects around 1 in 10 people with ovaries (1). Despite being named as an “ovarian” syndrome, PCOS  has both reproductive and metabolic characteristics. Your metabolism describes the chemical processes that take place to keep you alive and your organs functioning normally, such as breathing, repairing cells and digesting food. Many PCOS sufferers are prescribed a drug called metformin to help treat symptoms of the condition. Metformin is a medicine used to treat type 2 diabetes and metabolic syndrome, which is a combination of diabetes, high blood pressure (hypertension), dyslipidemia (high levels of fat in the blood), and obesity (2) If you’re a cyster who has been prescribed metformin to manage your PCOS, or if you have recently been diagnosed and want to know more about different treatment options, we’ve covered all you need to know about PCOS and metformin right here. 

What are the metabolic symptoms of PCOS? 

Before we understand how metformin can be used for people with PCOS, let’s understand the symptoms that affect the metabolism in many people with the condition. Whilst PCOS symptoms vary from person to person, insulin resistance is a common symptom within cysters (3). Insulin is a hormone released by the pancreas after a meal that allows all the other organs to take energy from your food in the form of glucose. With PCOS, the cells of the body are “resistant” to insulin and it struggles to help cells take in glucose from your food. In order to compensate, your body will produce even more insulin. 

Unfortunately, excess insulin circulating around your body can have negative effects. Too much insulin puts you at a higher risk of obesity, developing cardiovascular disease, and type 2 diabetes. 

Additionally, too much insulin can have a direct effect on the ovary whilst it also indirectly affects the ovary by increasing the release of other factors, like insulin-like growth factor 1 (IGF-1) from the liver (4). Insulin and IGF-1 both act on the ovary to produce testosterone, which stops your egg-containing follicles from growing to their full potential. This leads to the ovary producing lots of small follicles, giving the ovary the appearance of many cysts, or “polycystic, however, none of these follicles are likely to progress to ovulation. The increased testosterone can also contribute to acne and hirsutism, which can be described as male pattern hair growth in women.

What does metformin do? 

Reducing the amount of insulin in the blood will also reduce testosterone production and restore hormonal balance. This can be done by achieving weight loss (in cases where PCOS cysters are overweight or obese), regular exercise, or with the help of drugs like metformin. Metformin makes your body more sensitive to insulin, so your body no longer needs to overproduce it for your cells to take in glucose. 

Metformin has been shown to help shift stubborn weight and reduce BMI in those with PCOS. It restores hormonal balance by reducing follicle-stimulating hormone (FSH), luteinising hormone (LH), and testosterone, all of which are otherwise elevated with the condition. It also reduces low-density lipoproteins, or so-called “bad” cholesterol. However, metformin has been shown to be most effective in those who have a BMI classification of overweight and does not have the same effect in people with a BMI classification of normal or obese (5).

In people with anovulatory PCOS, which means a failure to ovulate, metformin can regulate irregular menstrual periods and restore ovulation by restoring balance to the levels of circulation FSH and LH, two major players in regulating ovulation. The success of this was shown in a Cochrane review involving 702 women, which found those taking metformin had a higher pregnancy rate than those taking placebos (6). Furthermore, all evidence suggests metformin is also safe to take during pregnancy and while breastfeeding, with very low risks to the baby.

The effect of metformin on reducing testosterone often helps alleviate symptoms like acne and hirsutism, though it may take months to see the effects of metformin on hair growth (7). 

Are there any side effects?

As with all medications, metformin does carry the risk of side effects. These include nausea, bloating and wind. In more severe cases some people experience vomiting and diarrhoea. In order to avoid experiencing side effects, your doctor might recommend starting at a lower dose and increasing its use gradually. It’s also recommended to take metformin during or immediately after a meal. 

Before being prescribed metformin, your doctor is likely to send you for bloods to check your kidney and liver function. People with severe liver or kidney damage are at a high risk of developing a rare side effect of metformin called lactic acidosis. This means, if you suffer from kidney damage or severe liver disease, unfortunately, metformin will not be suitable for you (8). 

Take home message

  • Metformin is helpful for managing PCOS symptoms in overweight people and those with anovulatory PCOS. It is less effective in anyone with a normal or obese BMI and not suitable for women with kidney or liver disease. 
  • Metformin has some minor side effects like bloating and nausea but the risk of these can be lessened by gradually increasing your dose and taking metformin with meals. 
  • Metformin improves insulin sensitivity, restores hormonal balance, and can reduce the appearance of acne and excessive hair growth. 

If you have been diagnosed with PCOS, or have been experiencing symptoms that suggest you may have the condition, our experts are here to help you get the answers you deserve. Our at-home PCOS hormone tests have been developed to help you understand or reach a diagnosis, and our experts can guide you through your next steps to manage your symptoms and make plans for the future.

  1. https://www.nhs.uk/conditions/polycystic-ovary-syndrome-pcos/ 
  2. https://bnf.nice.org.uk/drug/metformin-hydrochloride.html 
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3277302/ 
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4200666/ 
  5. https://www.hindawi.com/journals/ije/2020/5150684/
  6. https://pubmed.ncbi.nlm.nih.gov/22592687/
  7. https://onlinelibrary.wiley.com/doi/full/10.1111/obr.12889
  8. https://www.royalberkshire.nhs.uk/patient-information-leaflets/endocrinology-use-of-metformin-in-pcos 

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