---
title: How do brain chemicals change during the menstrual cycle? | Niyora
description: Yes, brain chemicals change during the menstrual cycle in specific ways. One chemical involved in mood is lower during ovulation than before the period, and a
url: https://niyora.com/research/papers/monoamine-oxidase-and-free-tryptophan-in-human-plasma-normal-variations-and-1975/
---

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- How do brain chemicals change during the menstrual cycle?

Survey study, 1975

# How do brain chemicals change during the menstrual cycle?

Yes, brain chemicals change during the menstrual cycle in specific ways. One chemical involved in mood is lower during ovulation than before the period, and another is 20% lower before the period than at other times.

 Early or limited evidence

Healthy women (sample size not specified)

## What they did

Researchers measured two specific brain chemicals in blood during different phases of the menstrual cycle in healthy women. They also measured these chemicals at different times of day.

## What they found

One brain chemical was lower during ovulation than before the period. Another brain chemical was 20% lower before the period compared to other times in the cycle. Women had higher levels of this second chemical than men, with greater variability. One chemical showed a daily rhythm (lower at midday, higher at midnight), while the other did not.

## What it means for you

Brain chemicals do shift during the menstrual cycle, and these shifts might relate to mood changes. However, this was a methodological study to develop measurement techniques, not one that directly linked chemical changes to symptoms.

20%

reduction in one brain chemical before period

2

brain chemicals measured

## About the study

Original title Monoamine oxidase and free tryptophan in human plasma: normal variations and their implications for biochemical research in affective disorders Authors Wirz-Justice A, Pühringer W, Hole G et al. Journal Pharmakopsychiatrie, Neuro-Psychopharmakologie Year 1975 Study design Survey study What was tested None Read the paper [doi.org/10.1055/s-0028-1094461](https://doi.org/10.1055/s-0028-1094461)

## Topics

[Sleep and insomnia](https://niyora.com/research/topics/symptom-sleep/)[Pregnancy and postpartum](https://niyora.com/research/topics/comorbidity-postpartum/)

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