Everything You Need to Know About Period Flu

If you often feel sick before you get your period, you may be experiencing what’s informally known as the period flu. The word "flu" is used because symptoms can include headaches, fatigue, and muscle pain, along with other physical, psychological, and emotional symptoms that are typically associated with premenstrual syndrome (PMS).

This article will explain what period flu is, its symptoms, duration, and treatments. It will also point out when you should see a healthcare provider.

Young woman feeling sick on the sofa at home

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Is the Period Flu Real?

“Period flu” is not a medical term. It describes various flu-like symptoms that some people experience before their period. These fluctuating symptoms are not in your head and their impact on your life can be significant.

Documenting your menstrual cycles and the symptoms you experience throughout the month can help you and your healthcare provider determine whether you have the period flu.

In some cases, your practitioner may want to rule out other medical conditions that can cause similar symptoms during your menstrual cycle, such as premenstrual dysphoric disorder (PMDD) and irritable bowel syndrome (IBS)

Period Flu Symptoms

Period flu symptoms vary. They can be hardly noticeable, mildly inconvenient, or severe. These symptoms can begin anywhere from a week or two before the first day of your period or during your period.

Common symptoms include:

  • Abdominal cramps and pain
  • Bloating
  • Back pain
  • Breast fullness, tenderness, and pain
  • Digestive problems including constipation and diarrhea 
  • Headaches
  • Muscle or joint pain
  • Problems concentrating
  • Skin breakouts (acne)
  • Sleep disturbances
  • Water retention
  • Vomiting 
  • Fatigue


The exact cause of period flu is unclear. These flu-like symptoms are hypothesized to be the result of hormonal fluctuations that take place during the menstrual cycle. 

Research suggests that the flu-like symptoms may be caused by a person’s reaction to a drop in progesterone levels during the latter half of the menstrual cycle.

Progesterone may also play a role as a neurotransmitter, a chemical messenger in the brain. For example, a drop in progesterone levels may affect your brain’s ability to modulate other chemicals related to how you feel, like serotonin (known as the "feel-good" hormone).

Hormonal Change Theory Explained

In the latter stage of your menstrual cycle, known as the luteal phase, your body releases an egg from an ovary. This is known as ovulation. If your egg isn’t fertilized, the sex hormones estrogen and progesterone drop sharply as your egg begins disintegrating and your uterine lining begins shedding. This hormonal drop is what’s typically associated with the flu-like symptoms.

Other theories on the potential causes of PMS include:

  • Allergy to progesterone
  • Carbohydrate metabolism changes
  • Estrogen-progesterone imbalance
  • Excessive aldosterone, or ADH (the hormone that helps regulate the metabolism of sodium, chloride, and potassium)
  • Hyperprolactinemia (an excessive secretion of prolactin, the hormone that stimulates breast development)
  • Retention of sodium and water by the kidneys
  • Low blood sugar
  • Psychogenic factors


Treatment options for PMS, which may include symptoms described as period flu, include:

  • Hormonal contraceptives: These may be prescribed to help improve hormone-related symptoms of PMS or PMDD.
  • Antidepressants: Selective serotonin reuptake inhibitors (SSRIs) may help with psychological symptoms. Most of the time they are prescribed daily, but sometimes are limited to just two weeks before your period begins.
  • Painkillers: Over-the-counter medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen may be used to reduce pain and aches.
  • Diuretics: Water pills may be taken to help reduce bloating (water retention).
  • Supplements: Calcium is often recommended, but other supplements, including vitamin D, herbal remedies like St. John’s Wort, and acupuncture, do not have enough evidence to support their recommendation.

Cognitive Behavioral Therapy for PMS/PMDD

Research suggests that cognitive behavioral therapy may help with PMS or PMDD. One 2019 study showed that the benefits of Internet-based cognitive behavioral therapy can help reduce the symptoms of PMDD. 

Lifestyle Choices and Prevention

Certain lifestyle choices can help prevent the emotional and physical impact of PMS. Generally speaking, any lifestyle choice that helps you stay healthy and avoid bloating, an upset stomach, mood changes, and sleep disturbance is helpful.

Specific lifestyle suggestions for coping with the period flu include:

  • Avoiding or reducing alcohol, caffeine, salt, and sugar intake
  • Eating a balanced diet, including plenty of whole grains, vegetables, and fruits
  • Exercising at least three to five times a week
  • Getting adequate and good sleep and rest
  • Quitting smoking

When to See a Healthcare Provider

If your symptoms are consistently severe and/or have a disabling effect on your mental health, contact your healthcare professional. You may be dealing with (PMDD). While less common than PMS, PMDD is a serious problem for 3% to 8% of all girls and women who experience PMS.

In addition, your provider may want to rule out other potential causes of your symptoms, such as digestive or gynecological problems.


While period flu is not an official diagnosis, the symptoms—which include flu-like symptoms such as body aches and digestive problems—can be disabling. They often exist in conjunction with PMS or PMDD. Lifestyle strategies, medications, and psychotherapy are often helpful in preventing or reducing symptoms of period flu.

Frequently Asked Questions

  • Are painful periods a sign of something serious?

    Not usually. As many as 90% of women experience some pain or discomfort with their periods. Often, that discomfort can become intense, but this is commonly a result of normal menstrual cramps and is known as primary dysmenorrhea. Secondary dysmenorrhea, however, could be caused by an infection, ovarian cysts, endometriosis, or other gynecological health problems. Talk to your healthcare provider about pain that's new or different.

  • Is it normal to get diarrhea with your period?

    Yes. About 33% of women experience changes in their bowels during menstruation. In most cases, this results in diarrhea, but constipation can also be a problem. Continue to follow a healthy diet and avoid cravings for foods that could irritate your bowels.

  • When I feel sick before my period, is it all in my head?

    You're probably not imagining it. However, your mood or mental state may affect how you feel physically around your period. Mood disorders such as depression are common just before menstruation, and there's a link between emotional symptoms and gastrointestinal problems such as bowel disorders. 

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Office on Women's Health. Premenstrual dysmorphic disorder (PMDD)

  2. Boston Children’s Hospital. Premenstrual syndrome (PMS) symptoms and causes.

  3. Institute for Quality and Efficiency in Health Care. Premenstrual syndrome: overview.

  4. Hofmeister S, Bodden S. Premenstrual syndrome and premenstrual dysphoric disorder. Am Fam Physician. 2016;94(3):236-240. PMID:27479626.

  5. Shobeiri F, Araste FE, Ebrahimi R, Jenabi E, Nazari M. Effect of calcium on premenstrual syndrome: A double-blind randomized clinical trial. Obstet Gynecol Sci. 2017 Jan;60(1):100-105. doi: 10.5468/ogs.2017.60.1.100

  6. Weise C, Kaiser G, Janda C, et al. Internet-based cognitive-behavioural intervention for women with premenstrual dysphoric disorder: a randomized controlled trialPsychother Psychosom. 2019;88(1):16-29. doi:10.1159/000496237.x

  7. American Academy of Family Physicians. Dysmenorrhea.

  8. Bernstein MT, Graff LA, Avery L, Palatnick C, Parnerowski K, Targownik LE. Gastrointestinal symptoms before and during menses in healthy women. BMC Women’s Health. 2014;14(1):14. doi:10.1186%2F1472-6874-14-14

By Michelle Pugle
Michelle Pugle, BA, MA, is an expert health writer with nearly a decade of contributing accurate and accessible health news and information to authority websites and print magazines. Her work focuses on lifestyle management, chronic illness, and mental health. Michelle is the author of Ana, Mia & Me: A Memoir From an Anorexic Teen Mind.