Menstrual Cycle Syncing: Does It Really Happen to Women?

Menstrual Cycle Syncing: Does It Really Happen to Women?

There's a captivating phenomenon that often sparks curiosity and conversation: the alignment of menstrual cycles among women who spend a significant amount of time together.

It's a topic which has frequently sparked fascination, debate, and a curious blend of scientific inquiry and anecdotal evidence. The McClintock effect, often referred to as "cycle syncing" or "menstrual synchrony", is a phenomenon that suggests that when women spend significant time together - at work, home or if they simply share a strong emotional bond - their menstrual cycles might synchronise over time. 

But what exactly is cycle syncing, and does it hold any scientific validity? Let's delve into the intricacies of this phenomenon, exploring how it can influence women's health and the sense of community.

Understanding Menstrual Cycle Alignment

Cycle syncing, also known as menstrual cycle alignment, proposes that when women live, work, or spend time together, their menstrual cycles gradually align, leading to the onset of periods occurring simultaneously or in closer proximity than before. This idea gained traction following a 1971 study by Martha McClintock, suggesting that women in close proximity experienced synced menstrual cycles. However, subsequent research has presented mixed findings, leaving the concept in a space between anecdotal accounts and scientific validation.

The Science Behind the Phenomenon

The exact cause of menstrual synchrony is still a matter of scientific debate. Some theories suggest that it could be due to pheromones, which are chemical signals released by the body that can affect the behavior or physiology of others nearby. Others propose that it's merely a coincidence or a result of shared environmental factors, as menstrual cycles can naturally fluctuate in length.

Moreover, methodological issues in studying this phenomenon, including small sample sizes and varied methodologies, have made it challenging to establish concrete evidence supporting cycle syncing.

Nevertheless, there's ongoing exploration into potential biological mechanisms behind cycle syncing. Hormones like pheromones - chemical messengers possibly emitted by one woman and sensed by others - have been proposed as a potential influencer, yet conclusive evidence remains elusive.

Implications for Women's Health and Relationships

  • Community and Connection: Menstrual cycle alignment may foster a sense of community and empathy among women, creating a shared experience that can lead to stronger emotional bonds.
  • Health Awareness: Understanding menstrual health is crucial, and the phenomenon of cycle alignment can prompt discussions about reproductive health, menstrual irregularities, and related wellness practices.
  • Natural Health Solutions: At Nature's Help, we encourage a holistic approach to menstrual health. Our range of natural supplements and health products is designed to support women through the ebbs and flows of their menstrual cycles, whether they are in sync with others or not.

The Influence of the Moon:

Connecting menstrual cycles to lunar phases has long captured the imagination. Ancient beliefs intertwined the moon's cycles with women's reproductive rhythms. The lunar cycle, spanning about 29.5 days, nearly aligns with the average menstrual cycle. This connection has fuelled debate suggesting that the moon's phases could affect menstrual cycles, leading to ovulation or menstruation syncing with lunar cycles.

However, scientific studies are yet to embrace this notion. Research hasn't provided substantial evidence supporting a direct link between lunar phases and menstrual cycles. While some individuals might feel a connection or rhythm between their cycles and lunar phases, empirical data fails to support a widespread influence.  We must remember that science requires evidence to support theories, however while concrete evidence may not exist, it doesn’t mean that cycle syncing does not exist. There is so much of the human body that we don’t understand yet.

Historical and Cultural Beliefs:

Throughout history, various cultures have embraced beliefs associating women's reproductive cycles with celestial bodies, nature, or communal living. In some ancient traditions, women living in close proximity were thought to harmonise their menstrual cycles, symbolising unity, and interconnectedness among women.

Cultural anecdotes and rituals often highlight the significance of cycles, portraying menstruation as a time of empowerment, renewal, or even spiritual significance. While modern science offers alternative explanations, these cultural beliefs continue to resonate, emphasizing the communal and symbolic aspects of women's reproductive cycles.

Can Menstrual Cycles Align with Other Women?

Skepticism and Further Research

While menstrual synchrony has its believers, there is also skepticism in the scientific community. Some studies have failed to replicate McClintock's findings, suggesting that menstrual cycle alignment might be more perception than reality. Ongoing research continues to explore this intriguing subject.


The idea of menstrual cycle alignment among women is a fascinating concept that blends the worlds of science, health, and human relationships. Whether it's a biological reality or a shared perception, it opens up important conversations about women's health. 

While initial studies hinted at the possibility of synchronization, subsequent research has failed to definitively validate this phenomenon. Though science may not have all the answers, many women throughout history will attest to the fact that working, living, socialising with other women has a direct impact on the cycle of menstruation.

The fascination with this idea continues to spark curiosity and discussion, highlighting the multifaceted nature of women's health and the intricate interplay between scientific inquiry and cultural beliefs.

At Nature's Help, we recognize the importance of these discussions and offer products and resources to support women in every phase of their menstrual journey, synced or not (ha ha).

Written by Mona Hecke

Mona Hecke is a degree qualified Naturopath, nutrition specialist and health and wellness writer.

With over 20 years in the health industry, beginning with a focus on children and families, and a bestselling book ‘The Lunchbox Revolution’, Mona is now empowering women through education and conversation to take action and embrace change. Gut health, mindfulness, nutrition, hormones, and menopause are the topics that women want and need to know to create their healthy future.

Mona holds certifications in Lifestyle Coaching, Kinesiology, holistic herbal medicine, and nutrition.

A recognised leader in the health industry, Mona’s strong social media presence and passion for influencing change will continue to be a catalyst for health reform for the benefit of every Australian.

Learn more about Mona Hecke.

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