FeminismsSexuality and Gender

Does our period actually sync up with our flatmates?

For many people that experience periods, it’s a given that our periods inevitably sync up with the nearest uterus owners – usually being our flatmates. But is there actually any science that proves this?

The short answer? No.

But let’s have a look further into this.

Does period syncing actually occur?

periodDr Jack Pearson notes that the first research on period syncing occurred in the 1970s. This study looked at American college students who lived together in dormitories.

This study concluded that those students who were close friends with their flatmates experienced period syncing compared to those that weren’t close friends, even if they did live in the same room.

As a result of this study, it was suggested that menstrual syncing occurred as a consequence of the strong bond of friendship, which therefore meant more time for pheromone communication.

Since this study, the vast majority of research that has been conducted in terms of period syncing does not actually support this hypothesis. Therefore, there is actually not that much scientific support.

Why do some people think their periods sync?

Dr Pearson notes that there is a lot of issues with why there is a misconception that periods do actually sync. One of these instances is that with a small amount of research and common sense, if women’s cycles aren’t regular then it’s more than likely that menstruation will overlap when groups of menstruating individuals live together. For example, Dr Pearson states that their research found that only 13% of cycles are actually 28 days long.

This essentially means this is more down to chance than communication between our bodies with others. Sometimes periods align and sometimes they don’t. Dr Pearson notes that as a society we like to hear meaningful and interesting stories as opposed to things happening by chance – meaning this is where period syncing came about.

Additionally, it was previously believed that period syncing was an evolutionary strategy. Essentially, this meant a group of individuals would cooperate as such between each other in order to prevent them from becoming a harem for a single dominant male.

What this means is that if a group of menstruating individuals were all fertile at the same time, this meant a single male could not reproduce with them all. When this research was released, there was an increase in the visual presence of the feminist movement – which is one theory as to why this became so popular.

But what about pheromones?

Dr Pearson states that it has been suggested that a menstruating individual can smells different and therefore gives off different pheromones. This can happen at different stages of the menstrual cycle. For example, more ‘attractive’ pheromones (to non-menstruating individuals) have been suggested to be produced mid cycle when ovulation occurs.

This theory makes sense for those trying to conceive, as you would want to maximise the chance of success. However, research does not support this idea about a male-female pheromone attraction. However, there is no research to suggest about pheromonal communication between menstruating individuals.


Overall, I think it’s pretty fascinating and amazing stuff. Even though there isn’t enough research or science to back the idea of period syncing, our bodies are doing some pretty cool stuff. Additionally, I think people believe in the idea of period syncing because it provides a comfort to a subject that is still treated as a taboo in today’s society – ridiculous, I know.