MTHFR and PMDD: the methylation link

Author: Jessica Lloyd
Senior Vulvovaginal Specialist Naturopath | BHSc(N) | ISSVD, ISSWSH, BSSM, ATMS

Last reviewed: July 20, 2026

Premenstrual dysphoric disorder (PMDD) may be shaped in part by a genetic predisposition, the MTHFR gene variances, with impaired methylation.

In PMDD, neurotransmitters such as serotonin and dopamine are influenced by oestrogen and progesterone fluctuations in the luteal phase of the menstrual cycle¹. That is, from ovulation to the first day of menstrual bleeding.

The symptoms of PMDD include debilitating depression, anxiety, mental impairment and fatigue, amongst others. The nervous system and neurotransmitters are misaligned, though the nature of this is unknown².

During the methylation cycle, SAMe is produced, resulting in the synthesis and balancing of neurotransmitters.

People with MTHFR gene mutations may not produce sufficient SAMe to ensure proper neurotransmitter production and management. In one study, the MTHFR C677T variant was linked to more premenstrual depression, though mainly in women with low folate intake³. SAMe supplementation has good evidence in depression⁴, and in our clinical experience it can ease PMDD symptoms for some people in a relatively short space of time.

Why is SAMe so effective in this situation?

Unclear, but a theory is that if you have MTHFR genetic mutation issues and methylation problems, thus not producing sufficient SAMe, the brain likely already has low serotonin levels. In the luteal phase as oestrogen drops, serotonin levels are very low. We need serotonin to stay feeling happy and well.

MTHFR gene variations and methylation issues may not exist independently, with low zinc, B6 and iron all important for neurotransmitter production. Inflammation causes a reduction in neurotransmitters, and research links higher inflammatory markers, such as CRP, with more premenstrual symptoms⁵.

Getting tested for MTHFR variants will help you move forward in getting the right treatment, and if you need more support, book in with an experienced practitioner.

This article is general information and not a substitute for personalised medical advice. If you are struggling with PMDD symptoms, please see an experienced practitioner.