Skip to main content

The menstrual cycle involves a complex interplay of hormones that can have various effects on the immune system. During the menstrual cycle, levels of estrogen and progesterone fluctuate, which can affect the activity of immune cells.

Estrogen, for example, has been shown to enhance the activity of certain immune cells that target viruses and bacteria. During the first half of the menstrual cycle, when estrogen levels are high, this may help to protect against infections. Though, higher estrogen does not necessarily mean better health. 

Progesterone, on the other hand, has been shown to have immunomodulatory effects. It can suppress the activity of certain immune cells, which may help to prevent the body from attacking the developing fetus during pregnancy. However, this can also make women more susceptible to infections during the second half of the menstrual cycle, when progesterone levels are high.

During most of the luteal phase of the cycle (i.e. the second part of the cycle), the immune system is suppressed and much less likely to stage an inflammatory response. This suppression of the immune system during the luteal phase is associated with rising levels of progesterone and with cellular changes that influence testosterone” –Boutot, Maegan: The Immune System and the Menstrual Cycle.

Overall, while the menstrual cycle does involve changes in hormone levels that can affect the immune system, the immune system remains active and is constantly working to protect the body.

Women can take 1 tsp of immune support daily during the second half of their cycle  to help support their bodies immune system function when progesterone is high.


Boutot, Maegan. “The Immune System and the Menstrual Cycle.” Clue Period & Ovulation Tracker with Ovulation Calendar for iOS, Android, and watchOS, 24 Feb. 2020, 

Scheibl, P, and H Zerbe. “Einfluss von Progesteron auf das Immunsystem mit Berücksichtigung der bovinen Retentio secundinarum” [Effect of progesterone on the immune system in consideration of bovine placental retention]. DTW. Deutsche tierarztliche Wochenschrift vol. 107,6 (2000): 221-7.

Hall, Olivia J, and Sabra L Klein. “Progesterone-Based Compounds Affect Immune Responses and Susceptibility to Infections at Diverse Mucosal Sites.” Nature News, 12 Apr. 2017,

Leave a Reply

Shopping from Canada? Check out our Canadian version of the site!