Get unlimited access to everything VICE has to offer.

Turn off all ads on VICE.com

Exclusive New VICE Documentaries

Member Exclusive Features & Columns

Turn off all ads on VICE.com

Exclusive New VICE Documentaries

Member Exclusive Features & Columns

Turn off all ads on VICE.com

Exclusive New VICE Documentaries

Member Exclusive Features & Columns

4 Magazines Delivered to Your Door

Your Friends Swear Their Periods Sync Up. I Asked Experts for the Truth.

Actual science, or confirmation bias?

Share on X (Opens in new window)X

Share on Facebook (Opens in new window)Facebook

Share using Native toolsShareCopied to clipboard

If you’re a woman, you’ve likely heard about the phenomenon of periods “syncing up” between friends or roommates. Maybe you and your sister somehow ended up with the same cycle timing, or perhaps your cycle was late one month, so your period ended up falling during your roommate’s period. 

These coincidences might have convinced you that your cycle was actually “syncing up” with other women in your life’s cycles. But is that actually possible?

I spoke with women’s health experts on this common assumption to better understand the concept and its validity. Let’s dive in.

Can Women’s periods Actually Sync Up?

Contrary to popular belief, women’s cycles don’t actually sync up—at least, not according to science.

“The concept comes from a small study in the ‘70s, but researchers after this couldn’t really replicate the results,” says Dr Jody-Ann McLean (MBBCh, BSc), medical doctor and medical writer with expertise........

© Vice