Have you ever had to ask to borrow a tampon from your best friend, only to find out she's also on her period at the same time? You could chalk this up to coincidence, or, this intimate information might muster a small sense of pride, empowerment - or at the very least, camaraderie. 

While the hypothesis of synced periods has been experienced by countless women who remain in close proximity to each other over time, this old wives tale has not been scientifically proven. The original study, published in a 1971 issue of Nature magazine coined it 'the McClintock Effect', and proposed that one woman's pheromones could impact the timing of another woman's menstrual cycle whom she shared a sustained, physical closeness with in a way that resulted in the two experiencing menstruation simultaneously. 

For animals and insects, an individual's pheromones do influence the behavior of other animals of the same species. However, in humans, pheromones haven't been proven to work the same way. 

As wondrous as menstrual synchrony sounds, it isn't actually rooted in any scientific fact. According to Kate Watson of insider.com, "pure mathematical probability is the likeliest reason why women's periods sync up."

While your bestie's cycle can't interrupt the timing and flow of yours, are you now wondering what can?

Birth control can, as can high or extreme levels of stress. Chronic illness (restrictive eating disorders, for example, such as anorexia or bulimia) that have gone untreated can absolutely affect your period. Lastly, although exercising excessively can be good for your physical health, it can also impact your menstruation - or lack thereof.

Every woman's period is different. Some last for a week, others for just two days. Some women get theirs every twenty-one days, while others might only get theirs every thirty-five days. With such a spectrum of experience, you can almost guarantee at some point they will overlap.

So the next time you and your friend, family member, classmate or colleague are menstruating at the same time; while it might not be period-syncing, you can still take comfort in your collective experience knowing you're not going through it alone. And hey, it's always a great excuse to indulge in one of Ladykind's famous CBD Self-Care Parties!

Nani Dominguez

Nani is a writer, co-host of TFAW Project and Tsismis with Jen & Nani podcast shows, and communications consultant residing in Oakland, California. Visit notesbynani.com to learn more.