Infertility may not be the first thing you think of when you hear metformin, but this insulin-sensitizing drug can help promote ovulation and treat female infertility.
Metformin is an older medication that is a safe and effective treatment for type 2 diabetes and insulin resistance. Weight loss is a known side effect, so it is also used off-label for weight management.
While metformin is not technically a fertility drug, meaning that it is not what it is FDA-approved to treat, metformin can help with fertility for many people with polycystic ovary syndrome (PCOS) who are trying to get pregnant.

What Is PCOS?
PCOS is a common endocrine disorder affecting about 10% of women. It is the most common cause of anovulatory infertility in women.
Symptoms of PCOS include:
- Irregular menstrual cycles
- Decreased ovulation or anovulatory cycles
- Excessive hair growth on the face, chest, abdomen, and upper thighs
- Acne
- Thickened, velvety, darkened skin patches
People with PCOS are at increased risk for the following conditions:
- Infertility
- Insulin resistance
- Obesity
- Type 2 diabetes mellitus
- Abnormal blood lipids
These conditions are all related, and insulin resistance and obesity are common denominators. Since metformin treats insulin resistance and helps with weight loss, it would make sense that metformin would also help manage PCOS symptoms.1 However, many women with PCOS are able to maintain a healthy weight. Insulin resistance is more common in women with PCOS than in weight-matched women who do not have the syndrome.2

What Is Insulin Resistance?
Insulin resistance is a condition in which body cells do not respond as well to insulin. Early on, your pancreas responds to insulin resistance by increasing insulin production. Eventually, the pancreas cannot keep up, and you end up with an unhealthy combination of increased blood sugar and insulin.
Excess glucose not used by cells is stored in fat tissue, leading to weight gain. When blood sugar levels remain chronically high, it is diagnosed as type 2 diabetes. Insulin resistance, obesity, and type 2 diabetes are all related.
Insulin resistance also increases androgens and reduces sex hormone-binding globulin, further increasing androgens. Increased androgen hormones in women can lead to problems with ovulation.3
How Does Metformin Help You Get Pregnant?
How metformin improves ovulation and helps you get pregnant is not currently understood. However, research has shown that people with polycystic ovary syndrome who take metformin alone, with Clomid, or with in-vitro-fertilization treatments may have better results than those who do not.4
Metformin improves ovarian cycles and decreases the risk of gestational diabetes. Metformin increases the ovulation rate but does not necessarily increase the rate of live births.
Metformin has the following beneficial effects:
- Inhibits liver glucose production
- Increases fatty acid oxidation
- Inhibits gluconeogenesis
These effects would improve insulin sensitivity and reduce androgen levels. This can restore ovulation and normal menstrual cycles.2
What Are Metformin’s Side Effects?
Metformin’s most common side effects are gastrointestinal, including stomach upset, diarrhea, vomiting, and nausea. Taking metformin with a meal can help reduce these side effects.
The most serious side effects associated with metformin are liver dysfunction and lactic acidosis, both of which are rare. Provide your doctor with your complete medical history, especially if you have liver, kidney, or lung disease.
Metformin can cause vitamin B12 deficiency. Watch for symptoms associated with vitamin B12 deficiency, such as:
- Fatigue
- Muscle weakness
- Sore, red tongue
- Mouth ulcers
- Visual symptoms
- Pale or yellowing tinge to skin color
How Long Does It Take To Get Pregnant With Metformin?
In a study in which 320 women received metformin or a placebo for three months before fertility treatments, for nine months during treatment, and up to 12 weeks of gestation, there was an increase in pregnancy rates from 40.4% to 53.6%. The live birth rate also increased. Women with obesity experienced the greatest benefit from metformin.5
There are many potential causes of infertility. Metformin may help some women, especially if they have PCOS and obesity, ovulate and maintain a pregnancy. However, research also suggests that while metformin may increase ovulation, it may not increase live birth rates.4

Does Metformin Help With Weight Loss?
Metformin can help with weight loss and insulin resistance. While it does not take long for metformin to start working, it may take two to three months to notice weight loss and better blood sugar levels.
Women with obesity seem to experience more benefits when taking metformin to stimulate ovulation and increase fertility. In one study, people who took metformin for up to six months lost an average of 10 to 14 pounds, which was 5.6% to 6.5% of their body weight.6 In another study, participants lost between 4.5% and 6.5% of their body weight after taking metformin as part of a weight loss program.7 A weight loss of 5% of your body weight has been shown to have important health benefits.
Metformin can help you regulate your insulin levels, which can reduce androgens. This may also increase fertility.
If you have questions about metformin and its many uses, contact one of the treatment specialists at Invigor Medical.
