If someone told you PMDD is estrogen dominance or a progesterone deficiency, they're wrong. Your hormones are normal. That's not a guess, it's what the research consistently shows.

People with PMDD have normal circulating oestrogen and progesterone. Their hormone shifts across the cycle look the same as anyone else's. Not too much, not too little. So if it's not the hormones, what is it?

Normal hormones, abnormal response

The issue is the brain. Specifically, how your central nervous system reacts to the completely normal rise and fall of those hormones every cycle.

GABA and serotonin, two neurotransmitter systems, are unusually sensitive in PMDD to the normal fluctuation of progesterone and its metabolite allopregnanolone. That sensitivity is what triggers the intense emotional and physical symptoms in your luteal phase. Not the hormone level. The sensitivity.

Think of it as a communication problem, not a supply problem. The rise and fall of oestrogen and progesterone in the second half of your cycle is the trigger, and it's normal. What's different in PMDD is the brain's response to that trigger. Exaggerated. Dysregulated. We're sensitive, and our brain reacts badly to fluctuations most women don't even notice.

That's also why SSRIs can work fast for PMDD, sometimes within days, and why you can start and stop them around your cycle in a way you couldn't for standard anxiety or depression treatment. They're not fixing hormones. They're stabilising how your brain responds.

It's not just hormones. Genetics and brain function are in the mix too

Genetics, stress history, differences in brain structure and function, they all play a role. That's part of why PMDD doesn't look identical from one woman to the next, and why some women still struggle even with textbook-normal hormone levels. This is also part of why PMDD shows up as different patterns for different women, not one symptom timeline everyone fits into.

What this actually means for you

If a doctor has told you your hormones are out of balance, or that your symptoms are all in your head, or that you just need to fix your hormones to feel better, none of that lines up with the science. Your hormones are doing exactly what they're meant to do. The response to them is the issue.

That distinction changes what actually helps. It moves the focus toward working with your nervous system and neurotransmitter pathways, not chasing a hormone fix that was never the problem. That's the whole premise behind regulating your nervous system through the luteal phase, and it's a lot of what I work through with clients one on one. If you want to understand your own nervous system response properly instead of guessing at what might help, a 1:1 session is where we map that out.

Source

• Raffi ER & Freeman MP. The Etiology of Premenstrual Dysphoric Disorder: 5 Interwoven Pieces. MGH Center for Women's Mental Health; September 2017.