No one knows what causes PMS. It is likely that changes to the levels of estrogen and progesterone and individual sensitivity to these changes trigger PMS symptoms. These hormones affect levels of neurotransmitters such as gamma-aminobutyric acid, dopamine, and serotonin which in turn can affect mood. Some evidence suggests that suppressing estrogen can improve PMS symptoms,[1] and a deficiency of progesterone may worsen symptoms, but more research is needed.[2]
What causes PMS?
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•Last Updated: May 16, 2025
The exact cause of premenstrual syndrome is unknown, but it is likely related to changes in estrogen and progesterone levels and individual sensitivity to these changes, which can affect neurotransmitter levels and mood. Some evidence indicates that suppressing estrogen may alleviate symptoms, whereas a deficiency in progesterone could worsen them, though further research is necessary.