a cycle of changing hormones
the menstrual cycle is driven by a carefully timed sequence of hormonal changes, mainly involving oestrogen and progesterone. in the first half of the cycle, oestrogen rises to support the release of an egg at ovulation. after ovulation, progesterone increases and oestrogen fluctuates, and it's in this second half of the cycle, the luteal phase, that pms symptoms typically appear.
in the days just before a period, both oestrogen and progesterone drop sharply if pregnancy hasn't occurred. this drop is thought to be one of the main triggers behind pms, although researchers still don't fully understand exactly how it leads to the symptoms so many people recognise.
the brain chemistry connection
hormones don't just affect the reproductive system. they also interact with chemicals in the brain that influence mood, sleep and appetite, including serotonin. some research suggests that changing hormone levels may affect serotonin activity, which could help explain why pms often includes emotional symptoms like irritability, low mood or anxiety alongside physical ones. this is still an area of ongoing study, and individual sensitivity to these shifts seems to vary a great deal.
why some people notice it more than others
it isn't fully clear why some people experience noticeable pms and others barely notice a change across their cycle. it may come down to individual sensitivity to normal hormonal fluctuations rather than the hormone levels themselves being unusual. other factors that may play a role alongside hormones include:
- genetics and family history
- stress levels
- sleep quality
- overall diet and lifestyle
- underlying mood or health conditions
not a sign that something is wrong
it's worth remembering that experiencing pms doesn't mean your hormones are "unbalanced" or that something is malfunctioning. for most people, it's a normal, if unwelcome, response to the natural hormonal rhythm of the cycle. that said, understanding roughly why it happens can make it feel less confusing, and can help when thinking about which lifestyle habits might support you through the luteal phase.
when to seek support
because pms is so individual, what helps one person may do little for another. many people find that gentle, consistent lifestyle habits (good sleep, regular movement, a nourishing diet and stress management) support them through the luteal phase. if your symptoms feel severe, are getting worse, or are significantly affecting your daily life, it's worth speaking with a doctor or healthcare professional, who can help work out what's going on and what support is available.