- Hey, guys, my name is Steven
and I'm a fellow here at Buzzfeed.
This is gonna sound a bit weird
but let's just get right into it.
This video is about periods.
(fun and upbeat music)
So you know when you're talking to your friends
and they say something that you're not expecting at all?
Like, my sister and I,
are periods are synced?
Yeah.
And all I ccould really say is,
did you just say that your periods are synced?
So after that conversation all I could really think
about is how little I know about women.
Like how is that even possible
and is this something that every girl knows?
I asked some co-workers to help loop me in.
- It's not necessarily just women's periods.
It's any person in the world that gets a period.
I've only lived with women so I'm gonna say yes
but I'm sure there are nay sayers out there
that would tell you other wise.
- No, I don't think it's true at all.
I've tried to believe it for a long time.
It's never happened.
Now that you bring it up.
Kind of makes a lot of sense, doesn't it?
- I mean, I don't know.
- My period's really not up for negotiation.
It's like determined by birth control.
- Right.
- So, Amy's period is synchronized to my birth control.
- But you don't live together?
- We don't live together
but we do see each other everyday.
- I think there's definitely potentially an alpha period.
- What? - LIke when I lived
- with my room mate.
Yeah!
No, when I lived with my room mate in college
everybody synced up to her.
- I don't know, maybe my body was just craving
some structure that Hillary's body could provide.
- I'm happy to provide that for you.
- Thank you.
- Anything I can do for you.
- Thank you.
- Have you guys experienced that?
- Well, we do live together
and our cycles have kinda adjusted to each other.
- It's almost like every month
there was always a couple of days later.
- And slowly you guys just came together?
(laughing)
- [Jordan and Molly] Yes.
- Slowly but surely we were in sync.
- How does this even happen?
- I don't know.
Animal instinct stuff.
- Yeah, primal.
- Primal stuff.
- [Steven] Primal stuff.
Well, if I'm going to understand this completely,
I need to talk to an expert.
It's time for me to visit an OB-GYN.
For the very first itme.
- There was a psychologist back in 1972
named Martha Martha McClintock who published
a very high profile paper showing that in a dormitory,
women did synchronize their menstruation.
And this was very exciting because this was the first time
that pheromones were shown to affect human behavior.
- So, this is a thing then, right?
- Well, when it was first published,
it created a huge interest
because it was a revolutionary paper.
Since then, people have tried to replicate this.
They're some falling half and half.
Either supporting it or completely disproving it.
- Do you believe it's real?
- Given that there's no solid evidence,
I would have to say no at this point.
- And what about all the women
that I've talked to earlier?
They've all told me that it's happened.
What would you say to them?
- It's something which the field does not
know what to believe.
And so there's still more research being done.
- [Steven] Wow, so the science doesn't back it up.
But that was my cue to go and do my own research.
I needed to talk to a group of women who lived together,
who defined sisterhood.
It was time to go back to college.
- We're all part of a sorority
and we all live together.
We all just love together and live together.
- Are you all synchronized?
- Yeah, pretty much. - Yeah.
- So do you guys know how it works?
- I just think it's if you spend a lot of time together
and you're constantly around each other.
It'll eventually sync up.
- All right, it's not that I don't believe you guys
but I want to collect some data.
I was wondering if you guys could write down the date
of your period, the last period that you had.
I wanna collect them and I'm gonna see
how synchronized you guys are.
(dramatic music)
- Let's see here, Andrea yours was April 28.
- That's a Tuesday.
- April 28.
The day after, 29.
Wow, this is, there's no way.
The 28th.
There's no way!
(laughing)
- No, I remember it was three days
after sisterhood retreat.
- [Steven] I'm like actually in shock right now.
- [Girl] I'm not, I synced with my sister.
- [All] Yeah! - There you go.
- [Marisa] We knew but like when you're reading
it off the paper, like, oh, my God, yeah,
it is like true, there you go.
- Women's periods definitely sync up.
It's a known thing.
We've had periods for millions of years.
(laughing)
But it's definitely a known thing.
- So while science may not fully back up this claim,
I feel like it's gotta be a thing, right?
All the women I've talked to,
the research I've done.
It all point to the fact that menstrual cycles do sync up.
And if you think about it, that's pretty freaking cool.
- [Tess] When I was younger like when you started
getting it in middle school or whatever.
My friend's mom was like, if you touch someone,
it'll happen.
(laughing)