Does metformin cause missed periods? (+3 studies)

In this article, we will discuss whether metformin causes missed periods. We will also share how metformin influences periods, evidence from research, and other relevant information. 

Does metformin cause missed periods? 

No, metformin does not cause missed periods. Metformin is frequently used to treat irregular periods caused by polycystic ovary syndrome (PCOS). Thus, metformin is more likely to regulate your periods than cause missed periods. 

Metformin, a biguanide agent, is used to manage type 2 diabetes due to its ability to reduce sugar levels in the blood and enhance the response of cells to insulin. Due to its effects on insulin, it also helps to manage PCOS and irregular periods (1).

Missed periods can be caused by hormonal irregularities, health conditions, and different medications. You can be prescribed metformin for missed periods caused by PCOS. 

If you are prescribed metformin for diabetes, it is likely to aid you in regulating your periods as well. If you experience missed periods while taking metformin, it can be due to several reasons and you should reach out to your healthcare provider. 

How does metformin affect your periods?

One of the mechanisms through which metformin helps with diabetes is that it improves the response of the body to insulin that is otherwise impaired leading to a phenomenon called insulin resistance (1). 

Due to insulin resistance, the pancreas is compelled to produce more insulin. The elevated insulin levels in the body trigger the release of androgens which are male sex hormones. Increased insulin also decreases the levels of luteinizing hormones (1). 

The dysregulation of hormones in the body leads to PCOS and missed periods. Metformin reduces the levels of insulin in the body and helps to normalize the levels of hormones which ultimately regulate periods (1). 

Metformin can also aid in weight loss and obesity is a common cause of PCOS and missed periods. Thus, metformin is known to help with missed periods caused by excessive weight, PCOS, and diabetes mellitus (2). 

What does research suggest? 

Several studies have explored the impact of metformin in regulating periods and have found it effective. In one study, the effects of metformin on obese women who had PCOS and produced excessive amounts of insulin were observed (3). 

Findings from this study revealed that metformin successfully regulated the frequency of periods and decreased the levels of testosterone in the participants (3). 

Metformin is used in the long-term management of PCOS. In one study, metformin was used to treat PCOS in both obese and normal-weight women for 24 months. Metformin effectively regulated hormones and periods in this study (4). 

Another study aimed to test the efficacy of insulin-lowering treatment in managing PCOS and regulating periods. The study utilized metformin as an insulin-sensitizing agent and it was effective in regulating periods and improving fertility in women (5).

How is metformin used for missed periods?

Metformin is used off-label to manage PCOS which is the major cause of missed periods. Metformin is recommended when patients with PCOS also have diabetes mellitus or impaired glucose tolerance (2). 

Metformin can also be used in adolescents to manage PCOS. It is also prescribed to those patients who are not able to manage PCOS through lifestyle modifications or those who cannot be treated with hormonal contraceptives (2). 

Metformin is available in both immediate-release and extended-release (ER) formulations. The recommended starting dose of immediate-release metformin for PCOS is 500 mg once or twice a day (1). 

If you are taking an immediate-release formulation of metformin, you can cut the tablets. Do not cut or crush the tablets if you are using an ER formulation. You can take metformin with food to reduce the gastrointestinal side effects (1). 

It is better to take metformin same time daily for a consistent response. If you are using an ER formulation, swallow the whole tablet with a full glass of water. Taking the ER tablet with an evening meal is recommended(1). 

How to regulate your periods while taking metformin?

You may be prescribed metformin if you have diabetes or PCOS. If you experience missed periods in general or while taking metformin, you should do the following: 

Confirm the cause of missed periods: 

Metformin is rarely a cause of missed periods. While taking metformin, missed periods may be because individual responses to medication vary and the hormonal changes might be causing irregularity in the period cycle. 

If you experience irregular periods, first, you should get it checked by a healthcare provider to find out the reason behind missed periods. Periods can be missed due to the following reasons (6): 

medications health conditions 
  • antipsychotics like olanzapine and haloperidol
  • antiepileptics like gabapentin and carbamazepine 
  • antidepressants like Prozac, Lexapro, and citalopram 


  • PCOS
  • Cushing’s syndrome
  • hyperthyroidism
  • prolactinomas
  • androgen-secreting tumor of the ovary or adrenal gland
  • Asherman syndrome
  • primary ovarian insufficiency 

Lifestyle modifications: 

Lifestyle modifications are the first approach to manage irregular periods and PCOS. Low-carbohydrate and calorie-restricted diets help regulate periods and also aid in weight loss. Obesity is also a common cause of PCOS (2). 

Incorporating healthy sources of foods like vegetables, fruits, lean proteins, nuts, seeds, and legumes is very helpful in regulating periods. Avoiding foods that cause rapid blood sugar spikes like highly processed and sugary foods is also important. 

Engaging in regular physical activity is also important as it helps to improve insulin sensitivity and reduce weight. Maintaining a healthy weight improves the symptoms of PCOS and regulates periods significantly. 

Stress management: 

Stress management is crucial in maintaining hormonal balance and overall quality of life in individuals with PCOS. Persistent stress can result in hormonal imbalance, insulin resistance, and unhealthy eating patterns which lead to missed periods.

Stress can be managed through meditation, deep breathing exercises, adequate sleep, and maintaining social networks for emotional support. 

In my experience: 

As per my understanding, metformin does not cause missed periods. In fact, it is used to treat missed periods caused by PCOS or overweight.

Metformin improves insulin sensitivity, helps with hormonal imbalance, and reduces weight and all of this helps to regulate periods. The efficacy of metformin in regulating periods is well established. 

If you experience missed periods while taking metformin, contact your healthcare provider to find the underlying cause. Periods can be regulated through lifestyle modifications and stress management along with taking metformin. 

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