--- title: What is happening in your brain: what the research says ยท Niyora description: What is going on in my brain? Genes, GABA, serotonin, and the add-back studies. This is the best-evidenced part of the research. url: https://niyora.com/research/mechanism/ --- - [Niyora](https://niyora.com/) - [Research](https://niyora.com/research/) - What is happening in your brain [Research](https://niyora.com/research/) # What is going on in my brain? Genes, GABA, serotonin, and the add-back studies. This is the best-evidenced part of the research, and it shows these symptoms have a physical cause. 5 findings. Best evidence here: **strong**. ## What is happening in your brain - Strong PMDD Your hormone levels are normal. The difference is how strongly your brain feels the shift. Same hormone levels in women who feel awful vs fine; the difference is brain sensitivity to normal shifts (~56% heritable) [Schmidt/Dubey](https://pmc.ncbi.nlm.nih.gov/articles/PMC10176022/) - Strong PMDD The calm chemical your body makes from progesterone drops before your period, and sensitive brains feel that withdrawal. Add-back paradigm ties symptoms to GABA / allopregnanolone (progesterone metabolite) withdrawal ["Genes to GABA" review](https://pmc.ncbi.nlm.nih.gov/articles/PMC10176022/) - Strong PMS / PMDD When estrogen dips after you ovulate, serotonin dips with it, and your calm system gets thrown off. Review: luteal estrogen drop lowers serotonin; reduced allopregnanolone sensitivity -> GABA/glutamate imbalance + HPA activation [Zinc/Cu/Mg review](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12647176/) - Moderate PMDD A big part of how strongly you feel this is inherited. GWAS: premenstrual symptom heritability ~35-57% [GWAS 2025 preprint](https://www.medrxiv.org/content/10.64898/2025.12.01.25341208.full.pdf) - Moderate PMDD Researchers can measure the difference in cells and blood flow. Cellular Ca2+/ER-stress + brain-blood-flow studies support the ESC/E(Z) sensitivity finding [ESC/E(Z) follow-ups](https://www.nature.com/articles/s41380-021-01144-8) [See all the research findings](https://niyora.com/research/), each with a link to its study. ## Keep reading [PMS anxiety](https://niyora.com/pms/anxiety/) ## Three steps for the moment it happens Niyora gives you three steps for that moment: reflect on what happened, regulate in about a minute, and respond with a clearer head. [Take the quiz](https://niyora.com/quiz/) [Get Niyora](https://apps.apple.com/app/niyora-pms-emotions/id6764561688)