We've all experienced period syncing, right?
You know it's real friendship when your periods sync up, right? I mean, I've lived with a lot of people who have periods, and it never ceases to amaze me how – once a month – we all morph into highly irate variations of the Hungry Caterpillar at *exactly* the same time.
Whether we're crying over literally nothing, or comparing notes on how menstruation masturbation is working out for us (surprisingly well – thank you v much), it definitely feels as though menstruation is something we all experience together, as oppose to errrm, taking turns.
For many people who have periods, it's a given that our periods will inevitably sync up with the nearest uteruses (usually belonging to our flatmates), but is there actually any science to back this up?
The short answer is no. GLAMOUR chatted to Dr Jack Pearson, who is the Medical Affairs Manager at Natural Cycles to find out why.
Is period syncing real?
To my knowledge the first research on period syncing was conducted in the 1970s which studied American college students living together in dormitories.
It found that those students that were close friends had menstrual cycles that synced compared to those that just lived in the same room whose cycles did not sync.
It was suggested that menstrual syncing occurred due to a strong bond which meant more time for pheromone communication.
Since then the majority of research that has been conducted into menstrual syncing does not support its occurrence and [the] studies that suggest that [period-syncing] exists have been poorly designed. So overall, there is not much scientific support.
Why do people think periods sync?
It’s very interesting to look at why there is a misconception that periods do sync! Firstly, small amounts of research and mathematical common sense suggest that if women's cycles are less regular then it's likely that menstruation will overlap when groups of menstruating individuals are living together – for instance, our research found that only 13% of cycles are 28 days long.
This is more due to chance than communication between our bodies. Sometimes they will align and others they will not. In society we like meaningful, exciting stories (period syncing being a thing!) whereas if things happen by chance it's generally not that interesting.
Secondly, it was believed this was an evolutionary strategy where individuals co-operate between each other to prevent them becoming a harem for a single dominant male.
If a group of menstruating individuals were all fertile at the same time, one male could not reproduce with them all.
Pretty primitive stuff! The release of this research coincided with an increase in the presence of the feminist movement which is one reason why the theory became so popular.
I believe the idea of syncing between individuals is also comforting given the taboo around menstruation and women's health.
If you are aware that someone close by is also on their period the idea of you both sharing this potentially difficult time gives you the feeling you are conquering this societal taboo together.
It has also been suggested that the attachment of mythical communication such as period syncing between women has roots in misogyny and that we should move away from the view that we'll never know the answers in women's health to performing good quality research on menstrual cycle data.
Where do pheromones come into this?
It has been suggested that a menstruating individual smells different (gives off different pheromones) at different stages of their menstrual cycle with more 'attractive' (to non-menstruating individuals) pheromones being produced mid cycle when ovulation is occurring.
This makes sense given that if you're trying to conceive, you want to have sex around the time that you ovulate to maximise the chance of success.
Research does support this idea (male-female pheromone attraction) but not that there is pheromonal communication between menstruating individuals (woman to woman cycle syncing).
This originally appeared on Glamour UK
