Metformin for PCOS: What to Know

Polycystic ovary syndrome (PCOS) is a condition that affects more than one in 10 women of childbearing age. Many people with PCOS struggle with hormonal imbalances that cause irregular periods, excess hair growth, and other symptoms, as well as fertility problems.

As an ex-doctor, I know that PCOS can be a real headache — it’s extremely upsetting having to tell patients that scientists are still unsure of why some people get a condition they struggle with, and that, sadly, there’s no cure for it.

So it shouldn’t come as a surprise that those with PCOS actively look for solutions themselves. If you’re one of them and have recently found out about a drug called metformin, here are some of the main things you need to know before asking your healthcare provider if it’s right for you.

What is PCOS?

PCOS stands for polycystic ovary syndrome, a condition that affects the ovaries, as well as other parts of the body. It’s found in around 7–10% of women in their reproductive age. People with PCOS may experience various symptoms, including:

Some of those affected by PCOS may present with multiple small fluid-filled sacs (cysts) in their ovaries seen by ultrasound, hence the name polycystic ovary syndrome.

PCOS is associated with trouble getting pregnant and a higher risk of certain health problems, such as high blood pressure and diabetes (including gestational diabetes mellitus or diabetes when pregnant), as well as endometrial cancer.

What causes PCOS, and what is insulin resistance?

Scientists are still uncertain of why some people with ovaries develop PCOS. It’s likely caused by many factors working together, including higher amounts of ‘male’ hormones, also known as androgens, as well as genetics. One of the factors that may play a role is resistance to insulin.

Insulin is a hormone that helps the body process sugar and use it for energy, and insulin resistance is a condition in which the body’s cells do not respond as expected to the said hormone, leading to high insulin and sugar levels in the bloodstream.

Eventually, the balance between ‘male’ and ‘female’ hormones in the body may be disturbed. Excessive amounts of androgens may lead to hair growth in unusual places, such as the chin, and may contribute to acne, as well as problems with periods and fertility.

Abnormally high insulin levels may cause weight gain and vice versa — carrying excess weight contributes to resistance to insulin. As many as four out of five women with PCOS live with obesity.

How is PCOS managed?

Though PCOS cannot be cured, there are various options for managing the condition. Treatment is tailored individually according to various factors, including one’s symptoms, health status, and reproductive needs (meaning if the person wishes to get pregnant now or not).

For those not planning to become pregnant soon, healthcare providers may recommend:

• Hormonal birth control methods that are proven to help regulate the menstrual cycle, with some types providing relief from acne and excess hair growth
• Anti-androgen medicines that block the effects of androgens
• Lifestyle changes, including weight loss, which may help regulate the cycle
• Insulin-sensitizing drugs, such as metformin, that help the body use insulin more effectively and lead to improvements in several PCOS symptoms

Metformin and PCOS: the connection

Metformin is a prescription drug that helps control the amount of sugar (glucose) in the blood and increases the body’s response to insulin. Therefore, it’s typically used as a first-line treatment for managing type 2 diabetes, which is a condition in which the body doesn’t use insulin normally, leading to abnormal glucose levels in the bloodstream.

Knowing that the symptoms of the syndrome and resistance to insulin are closely connected, metformin may be used to manage the symptoms of PCOS.

While metformin is not approved by the U.S. Food and Drug Administration (FDA) for the treatment of PCOS, its off-label use for managing PCOS symptoms is acknowledged by many major women’s health bodies, including the American College of Obstetricians and Gynaecologists (ACOG).

How does metformin work for PCOS?

Metformin works by helping the body respond to insulin or, in other words, improving insulin sensitivity. It’s been shown that biguanides, the drug class metformin belongs to, may lead to improvements in PCOS characteristics and symptoms, including:

• Improve ovulation, which may help regulate periods and make them more predictable
• Improve glucose tolerance (how the body responds to sugar) and reduce the risk of developing diabetes in those with impaired (abnormal) glucose tolerance
• Decrease androgen levels and therefore manage symptoms associated with the excess levels of ‘male’ hormones, though its effect on acne and extra hair on the face or body is debated

A 2023 scientific review and meta-analysis published in the European Journal of Endocrinology has suggested that metformin, when used hand in hand with lifestyle changes, could be an effective treatment method in adult women with PCOS that could improve not only resistance to insulin but also weight loss and lipid (fat molecule) concentrations in the blood, especially in those with a higher body mass index (BMI).

PCOS, fertility, and metformin

As briefly mentioned above, PCOS may lead to anovulatory infertility and affect one’s chances of getting pregnant. Though many people with PCOS do get pregnant naturally, others may require some help. For those who wish to become pregnant with PCOS but are struggling to do so on their own, multiple treatment options — from drugs to induce ovulation to in vitro fertilization (IVF) — may be suggested.

Metformin is prescribed to those who are not currently trying to conceive. However, due to its health effects, it’s known that it may stimulate fertility, making it important to use reliable methods of contraception for those who are sexually active.

How is metformin for PCOS used?

Metformin is a prescription drug, meaning people can only take this medication under the guidance of their healthcare provider, who evaluates whether this is a suitable treatment option.

Doctors also explain how to and for how long to use metformin, as well as what dose is suitable for PCOS. While it may vary by person, according to ACOG, the dose most commonly used to treat PCOS is 1,500–2,000 mg per day given in divided doses.

Metformin comes as a tablet or a liquid taken by mouth and is intended to be taken every day once or multiple times, depending on the formulation. Doctors often suggest starting at a lower dose and then increasing the dose slowly in order to help lessen the risk of experiencing unpleasant side effects.

Metformin for PCOS: adverse effects and health risks

If you’re thinking of discussing taking metformin with your healthcare provider, you may wonder whether taking it may lead to side effects.

People taking metformin may experience various adverse effects. Most commonly, they affect the stomach and the bowel, and may include:

Most often, these side effects occur first when the drug is taken. While taking metformin is rarely associated with causing low blood sugar levels (hypoglycemia), it carries a small risk of lactic acidosis, which is a serious, life-threatening condition in which lactate — a natural byproduct of metabolism — builds up in your blood, leading your pH levels to become too acidic.

Metformin may not be suitable for all people, including those with severe kidney problems. Make sure to clear all of your concerns with your doctor, including your past or current illnesses and drugs you’re taking, and be honest while answering all of their questions. This will help them decide whether taking metformin could be a fitting and safe treatment option for you.

PCOS and metformin: the takeaway

While PCOS cannot be cured, metformin may offer a promising option for managing its symptoms. Through its ability to improve insulin sensitivity, metformin’s benefits include the potential to help decrease circulating androgen levels, regulate menstrual cycles, and improve ovulation.