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Does Mounjaro Affect Your Periods (Menstrual Cycles)

Mounjaro and Periods

Mounjaro will affect your periods if you are experiencing changes in body weight with it. Mounjaro may not directly affect your hormones but it melts down your body fats.

Changes in body fats have an influence on your periods as the balance between estrogens and progesterone is disrupted.

Estrogen and progesterone are the two primary hormones responsible for female sexual health and timely menstrual cycles.

A change in body weight has been identified as one of the key factors that influence women’s periods. 

It is not always obesity or being overweight that you’ll notice changes in your cycles. Thin lean women also have menstrual problems and sometimes have a complete absence of menstrual cycles.

Another important factor is the rapid weight gain or more importantly rapid weight loss which significantly alters the duration, intensity, and flow of your menstrual bleeding.

A “U” shaped pattern of changes in menstrual cycles and body weight was observed in one clinical trial in Korea [Ref].

u curve association of body weight and menstrual cycles
u curve association of body weight and menstrual cycles

The “U curve” suggests that at the extremes of body weight and BMI, the cycles become abnormal.

Most women have scanty flow and a reduced number of days of periods, however, menorrhagia (increased flow or duration of flow) can also occur. 


Mounjaro and Periods (Menstrual Cycles):

Regular and timely female menstrual cycles are dependent on many factors. The most important factor influencing menstrual cycles is female hormones. The second most common factor is the body weight or change in body weight.

Body weight has other direct and indirect effects. It also alters the balance between estrogen and progesterone which directly affects the menstrual cycles.

Since Mounjaro is one of the most potent medicines associated with weight loss, it is probably more likely than other weight loss drugs to cause a change in your menstrual cycles.

Most women who reported changes in menstrual cycles were those who had the greatest weight loss. The change was greatest in obese individuals who had scanty menstrual cycles or had very brief and delayed menstrual cycles.

These women reported a positive effect on their monthly periods with Mounjaro. Here are some of the comments women shared about their experience using Mounjaro (Tirzepatide):

“For years, I have experienced irregular periods, which became even more unpredictable and irregular after using a hormonal IUD.

However, since starting MJ around 11 weeks ago, I have surprisingly had two normal cycles, which is a first in my life.

Although the bleeding and cramping are more intense, the fact that it lasts only 5-7 days instead of 17-40 is nothing short of a miracle for me.”



It’s truly remarkable how these medications can make us feel younger. I’m experiencing a period that I never had during my youth, and it actually feels like a positive development. It seems that my body is finally functioning as it should. 


 My menstrual cycles were dreadful – heavy, painful, and completely unpredictable.

Even before I started using MJ, I had discontinued birth control in my late 40s. The situation worsened to the point where my doctor recommended a hysterectomy due to complex hyperplasia.

However, after eight months and a weight loss of 35 pounds on MJ, my periods have become light, shorter (maximum of 3-4 days), and consistently regular. Interestingly, my Apple Watch accurately predicts when I’ll start each month.

I had hoped that at 50, my periods would begin to fade, but thanks to MJ, everything seems to be regulated, and my doctor now says I’m right on track for perimenopause.

Fortunately, I no longer require a hysterectomy and can naturally transition into menopause. Although I would have preferred for them to disappear altogether, I’m extremely grateful that my body seems to be functioning normally again.


 I suppose I’m among the minority who actually appreciates having my periods. When I began using MJ, I went without one for over three months, and it truly bothered me. I sincerely hope that moving forward, my menstrual cycle remains regular.


I’m currently on day 8 of Mounjaro (I took my second 5mg shot yesterday), and it’s day 6 of an unexpected period. Whenever I lose more than approximately 5 pounds after being at a plateau for a while, I tend to experience an additional period or a heavier flow.

However, after a few weeks, things usually return to a new normal (although not necessarily exactly the same as my previous cycle).

For me, an abnormal period accompanied by weight loss serves as a signal that my weight loss is more than just water.



To regulate my menstrual cycles during perimenopause, I follow a consistent schedule of taking cyclical hormones, specifically oral birth control. However, one notable difference I’ve observed is that my periods have become noticeably heavier than usual with Mounjaro. 

With a weight loss of more than 5% of your body weight, and especially body fats, your sex hormones that are in bound form are released into your blood. These hormones are responsible for the change in your menstrual cycles.

Since most women who had untimely periods, had them in many months, they felt the same pain as when they had periods during their teenage.

This is why most women, apart from reporting having menstrual cycles after months, had heavy and painful periods.


Mounjaro and Premenstrual Syndrome:

Premenstrual syndrome is a state of physical and psychological discomfort that is experienced by women who are about to have their monthly periods.

Days before the menstrual cycle, women may develop cravings for foods, develop body swelling, bloating, breast pain and tenderness, fatigue, headache, and anxiety.

Women may notice a fluctuation in their mood, develop mood swings, and their sleep may get disturbed.

The effect of Mounjaro on premenstrual syndrome is not yet known. However, most women do experience some of the symptoms, especially bloating, insomnia, fatigue, and headaches which are common side effects of Mounjaro and are commonly observed by women with premenstrual syndrome.

On the other hand, women on Mounjaro do not crave food or sweets during their premenstrual syndrome as they had it before and so weight gain and swelling is minimal.


Mounjaro, Body Weight and Periods:

Mounjaro is one of the most potent medications for weight loss in women with diabetes. It has been associated with up to 24% body weight loss which is greater than Ozempic (Semaglutide).

There are no studies yet that have evaluated and correlated the percentage of weight loss with the change in menstrual cycles. However, theoretically, women who have the most weight loss with Mounjaro, are likely to experience more significant changes in their periods.

Obese women with PCOS may notice more regular and timely periods. Similarly, women may notice more cramps, pain, and heavy bleeding.

Mounjaro and PCOS:

Mounjaro is one attractive treatment option for women with PCOS. It has been observed that GLP-1 stimulation is required for follicle maturation.

In addition, Mounjaro (Tirzepatide) helps in relieving the symptoms of insulin resistance and the dysregulation of sex hormones.

Obesity, insulin resistance, and dysregulation of sex hormones, primarily estrogens, are responsible for most symptoms of PCOS.

Mounjaro targets all three components and may improve the symptoms of PCOS and help women with PCOS to conceive, especially those who are struggling to get pregnant because of their excessive body weight.

It is important to note that Mounjaro (Tirzepatide) should be stopped at least a month before a planned pregnancy.

In case you get pregnant, you should immediately stop Mounjaro and consult your doctor.


In Conclusion:

In conclusion, Mounjaro (Tirzepatide), as a GLP-1 and GIP analog, has shown significant potential for weight loss.

It has also been observed to have a positive impact on regularizing menstrual cycles in women with infrequent and irregular periods.

However, it is important to note that some women may experience heavy and painful bleeding as a result. Further studies are required to fully understand the effects of Mounjaro on menstrual cycles.

What do you think?

Written by Dr. Ahmed

I am Dr. Ahmed (MBBS; FCPS Medicine), an Internist and a practicing physician. I am in the medical field for over fifteen years working in one of the busiest hospitals and writing medical posts for over 5 years.

I love my family, my profession, my blog, nature, hiking, and simple life. Read more about me, my family, and my qualifications

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