Drugs Q & A

Does Metformin Affect Your Menstrual Period?

Menstruation is the shedding of the lining of the uterus (endometrium) accompanied by bleeding. It occurs in approximately monthly cycles throughout a woman’s reproductive life, except during pregnancy. Menstruation starts during puberty (at menarche) and stops permanently at menopause.

By definition, the menstrual cycle begins with the first day of bleeding, which is counted as day 1. The cycle ends just before the next menstrual period. Menstrual cycles normally range from about 25 to 36 days. Only 10 to 15% of women have cycles that are exactly 28 days. Also, in at least 20% of women, cycles are irregular. That is, they are longer or shorter than the normal range. Usually, the cycles vary the most and the intervals between periods are longest in the years immediately after menstruation starts (menarche) and before menopause.

Regular periods can vary. If your regular cycle is 28 days and you still have not had your period on day 29, your period is officially considered late. Likewise, if your regular cycle is 32 days and you still have not menstruated on day 33, this would be late for you.  Missed or late periods happen for many reasons other than pregnancy. Common causes can range from hormonal imbalances to serious medical conditions. There are also two times in a woman’s life when it’s totally normal for her period to be irregular: when it first begins, and when menopause starts.

What is Metformin?

Metformin is a prescription drug used to treat type 2 diabetes. It belongs to a class of medications called biguanides. People with type 2 diabetes have blood sugar (glucose) levels that rise higher than normal. Metformin doesn’t cure diabetes. Instead, it helps lower your blood sugar levels to a safe range.

Metformin is also often prescribed off-label to treat polycystic ovary syndrome (PCOS), but it isn’t currently FDA-approved for this use. Metformin oral tablet comes in two forms: immediate-release and extended-release. The immediate-release tablet is available as a generic drug. The extended-release tablet is available as the brand-name drugs Fortamet and Glumetza.

Metformin can cause mild and serious side effects. Most side effects are mild and primarily affect your digestive system. Severe side effects such as lactic acidosis are less common but require prompt medical attention.

How Metformin works

Metformin belongs to a class of drugs called biguanides. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Metformin works by:

•          reducing the amount of glucose (sugar) made by your liver

•          decreasing the amount of glucose your body absorbs

•          increasing the effect of insulin on your body

Insulin is a hormone that helps your body remove extra sugar from your blood. This lowers your blood sugar levels.

How should I take Metformin?

Metformin comes as a liquid, a tablet, and an extended-release (long-acting) tablet to take by mouth. The liquid is usually taken with meals one or two times a day. The regular tablet is usually taken with meals two or three times a day. The extended-release tablet is usually taken once daily with the night meal.

Metformin is usually started as 500 mg by mouth twice daily or 850 mg by mouth once daily. Depending on how well it works, the dose can be raised to a total of 2,550 mg by mouth per day split into a few doses throughout the day.

To help you remember to take metformin, take it around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take metformin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow metformin extended-release tablets whole; do not split, chew, or crush them.

Your doctor may start you on a low dose of metformin and gradually increase your dose not more often than once every 1–2 weeks. You will need to monitor your blood sugar carefully so your doctor will be able to tell how well metformin is working.

Metformin controls diabetes but does not cure it. Continue to take metformin even if you feel well. Do not stop taking metformin without talking to your doctor.

Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.

Does metformin affect your period?

Yes, metformin can affect your menstrual period especially if you are suffering from polycystic ovary syndrome (PCOS), a hormonal disorder common among women of reproductive age.

This condition causes the body to produce more male hormones, which can result in irregular menstrual cycles, or may even stop menstruation altogether. Metformin treatment, however, can lower insulin and blood sugar levels in women with PCOS, stimulating ovulation and encouraging regular monthly periods.

When metformin was used in addition to other medication, there was a more significant restoration of menstrual cycles. Using metformin can be highly effective in treating menstrual irregularities experienced among patients with the polycystic ovarian syndrome.

Can I take metformin while on my period?

Yes, you can take metformin while on your period, but it is not uncommon to experience a heavy period after starting metformin. 

How long does metformin take to regulate periods?

Within 6 months of starting treatment with metformin, women with polycystic ovary syndrome (PCOS) will not notice an improvement in menstrual cycle regularity. Discuss with your doctor if you started metformin and have a missed period with a negative pregnancy test.

Metformin side effects

Metformin can cause mild or serious side effects. The following list contains some of the key side effects that may occur while taking metformin. This list does not include all possible side effects.

More common side effects

The more common side effects that can occur with metformin include:

•          stomach problems:

o          diarrhea

o          gas

o          heartburn

o          nausea

o          stomach pain

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

•          Lactic acidosis. Symptoms can include:

o          dizziness or lightheadedness

o          slow or irregular heart rate

o          stomach pains, nausea, or vomiting

o          tiredness

o          trouble breathing

o          unusual muscle pain

o          unusual sleepiness

o          weakness

•          Hypoglycemia (low blood sugar). Symptoms can include:

o          confusion

o          dizziness

o          drowsiness

o          fast heart rate

o          headache

o          hunger

o          irritability

o          shaking or feeling jittery

o          sweating

o          weakness

•          Low vitamin B12 levels. Symptoms can include:

o          loss of appetite

o          low energy

o          muscle weakness

o          tingling or numbness in the hands or feet

Metformin may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program by phone (1-800-332-1088).


Dr. Oche Otorkpa PG Cert, MPH, PhD

Dr. Oche is a seasoned Public Health specialist who holds a post graduate certificate in Pharmacology and Therapeutics, an MPH, and a PhD both from Texila American University. He is a member of the International Society of Substance Use Professionals and a Fellow of the Royal Society for Public Health in the UK. He authored two books: "The Unseen Terrorist," published by AuthorHouse UK, and "The Night Before I Killed Addiction."
Back to top button

Adblock Detected

Please consider supporting us by disabling your ad blocker