Is Metformin A Good Treatment For PCOS?

Have you considered clinical trials for Polycystic ovarian syndrome (PCOS)?

We make it easy for you to participate in a clinical trial for Polycystic ovarian syndrome (PCOS), and get access to the latest treatments not yet widely available - and be a part of finding a cure.

What is PCOS?

Polycystic ovary syndrome (PCOS) affects between 6% and 12% of women in their childbearing years. PCOS occurs when there's an imbalance of the reproductive hormones in your body, which plays havoc with your ovaries releasing healthy eggs on schedule.¹

The ovaries are supposed to release an egg every month (and when that egg isn't fertilized, you get your period). But with PCOS, the egg doesn't develop, or it doesn't release during ovulation. This causes irregular periods, which is one of the signs that you may have PCOS. 

PCOS is a major cause of infertility. It can lead to the development of ovarian cysts, tiny fluid-filled sacs that make more of the hormone androgen than your body needs — causing problems for your menstrual cycle. 

PCOS is a disease that affects your reproductive system, but the complications of the disease aren't confined to your uterus. It has a high degree of morbidity — meaning several long-term consequences and health problems. 

Many women with PCOS are obese or overweight and have also shown unusual levels of insulin resistance (IR), although these two conditions are not part of the diagnostics for PCOS. These are some of the complications of PCOS:

  • Type 2 diabetes

  • Metabolic syndrome

  • Cardiovascular disease

  • Hypertension

  • Endometrial cancer

  • Gestational diabetes

  • Sleep apnea

  • Anxiety and depression

Risk factors for PCOS

Your risks for PCOS are a combination of genetics and lifestyle choices. Insulin resistance is the primary culprit, and that too can be hereditary or the result of dietary and exercise habits. 

Insulin resistance 

The common denominator for PCOS appears to be insulin resistance — when your muscles, fat, and liver don't use the insulin your body produces efficiently and can't easily absorb glucose from the blood. This sends your pancreas into an insulin-producing overdrive, and so long as it can make enough insulin to make up for your cells' poor response, your blood glucose levels are okay. 

Some medications can lead to IR — for example, steroids, which you might take to reduce inflammation or a rash, and antipsychotics. Cushing's syndrome, when your body overproduces steroids, and sleep apnea, can also cause IR.²

Hereditary risk factors

If your mother or sister has PCOS, chances are you'll have it, too. These are other genetic factors that may cause PCOS: 

  • Ethnicity

  • Weight

  • Family history of hyperandrogenism

  • History of metabolic disorders  

Symptoms and causes of PCOS

When you have PCOS, one of the effects is that your body produces too much of the hormone androgen. Your body produces several hormones related to reproduction, but abnormal levels of the pituitary luteinizing hormone and increased amounts of the hormone androgen hamper ovarian function. 

Although androgen is considered a "male" hormone because it is associated with testosterone, it plays a key role in fertility — starting with converting into estrogen to start puberty. In the normal progression, androgen leads to underarm and pubic hair growth as external signs. Internally, androgen regulates organ function and promotes estrogen synthesis and bone density. 

When your body produces high levels of androgens, one of the signs is hirsutism — excessive hair growth on the face and body and thinning hair on the scalp. 

Other subtle symptoms of PCOS may include:

  • Irregular, missing, or very light periods

  • Unexplained weight gain, especially around the belly

  • Unusually oily skin or acne

Your doctor may find other signs of PCOS with an internal exam, namely enlarged or cystic ovaries. Infertility is also a common symptom of PCOS. 

Finally, in many women, PCOS can increase the risk of developing type 2 diabetes.

What about metformin to treat PCOS?

Metformin is an oral medication that lowers blood sugar levels, but it is somewhat controversial as a first-line medication against PCOS. It is recommended for the treatment of type 2 diabetes but has not been approved for either pre-diabetes or PCOS — however, doctors often prescribe it as an off-label treatment. 

How does metformin help PCOS treatment?

Metformin may be a beneficial therapy for women with PCOS who are trying to get pregnant. For women who are not obese, it can help stimulate ovulation. It has the added benefit over clomiphene citrate (CC) because there is no known negative endometrial effect, whereas CC can cause thinning of the endometrium, reducing embryo receptivity. 

There is also a much lower risk of multiple pregnancy with metformin. However, CC is the better option for obese patients. 

Doctors caution that to get the most benefits from metformin, you should make dietary and physical lifestyle changes. 

Here's why. A study measured the efficacy of metformin, CC, and other pharmaceuticals against lifestyle changes. The outcome variables the researcher was looking for were the following:³

  • Change in menstrual cycle

  • Waist circumference

  • Endocrine parameters

  • Lipid profile

These were the results for clinical pregnancies:

  • CC group — 12.2%

  • Metformin — 14.4%

  • CC + metformin — 14.8%

  • Lifestyle modification — 20%

Given the 5% swing between changing your diet and exercise habits and taking a combination of drugs with many side effects, making those lifestyle changes may well be better for you in the long run.

 Potential side effects

Women who take metformin should be aware of the possible side effects:

  • Nausea and vomiting

  • Diarrhea

  • Stomach ache

  • Loss of appetite

  • Vitamin B12 deficiency

  • Metallic taste in your mouth

  • Flatulence and bloating

What is a normal dose of metformin for PCOS?

Your doctor will likely prescribe metformin for a week or two. You should take it with food to reduce the possibility of side effects. Dosage increases weekly or biweekly by 500mg daily until you are up to a dosage you can tolerate or are taking the maximum of 2500mg per day.

Alternatives to metformin

There are several alternatives to metformin. Which one you and your doctor choose should be guided by whether you want to be pregnant. 

If you're not interested in getting pregnant anytime soon, a hormonal birth control — oral contraceptive, a patch, Mirena, vaginal ring, or depo shot — that blocks ovulation can have these benefits:

  • Regulate menstrual cycle

  • Reduce risk of endometrial cancer


Berberine, a staple of Chinese medicine, is a plant-based chemical with similar properties to metformin. The European Journal of Endocrinology published the results of a study of Chinese women with insulin resistance and PCOS, comparing the effects of berberine and metformin.⁴

Overall, berberine lowers total testosterone, fasting glucose, and fasting insulin levels. It also resulted in a lower BMI and improved cholesterol levels. 


A promising new group of therapeutics for PCOS are inositols. Myo-inositol and D-chiro-inositol have both shown that they are safe alternatives to metformin. 

Some benefits of using inositols include: 

  • Lower testosterone levels

  • Improved insulin sensitivity

  • Reduced hirsutism

  • Improved ovarian function

What makes inositols even more appealing is that they do not have the side effects of metformin. 

The lowdown

Women with PCOS have an increasing number of treatment options, both pharmacological and natural. Researchers are continuing to find better medication to control the disease. But doctors maintain that one of the best ways to manage PCOS and the type 2 diabetes that usually accompanies it is to maintain a healthy lifestyle. 

Obesity, insulin resistance, and PCOS appear to be intertwined, and it's more common to find a woman with PCOS who is overweight or has problems with insulin resistance. The ideal scenario is for patients to get their weight and BMI under control, which generally leads to better overall health and improves insulin sensitivity. 

Determining whether metformin is right for your particular diagnosis is a decision you should make with your doctor. If you haven't been diagnosed with PCOS but have the symptoms, make an appointment with your healthcare provider as soon as possible to confirm the diagnosis and start a treatment plan.

  1. PCOS (polycystic ovary syndrome) and diabetes | Centers for Disease Control and Prevention

  2. Cushing's syndrome | National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

  3. An assessment of lifestyle modification versus medical treatment with clomiphene citrate, metformin, and clomiphene citrate–metformin in patients with polycystic ovary syndrome (2010)

  4. A clinical study on the short-term effect of berberine in comparison to metformin on the metabolic characteristics of women with polycystic ovary syndrome (2012)

Other sources:

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