Amy Hammer separates menstrual facts from fiction in a way that is both friendly and approachable. Packed with crucial information you may have missed in health class, Cycles gives you everything you need to reclaim and embrace all the seasons of your cycle.

—Amanda Laird, author of Heavy Flow: Breaking the Curse of Menstruation and host of the Heavy Flow Podcast

Why do (some) humans menstruate when most mammals don’t? Cycles offers a fascinating exploration of the science of menstrual cycles as well as the history of hormones, reproductive science, and a physiologic and symbolic understanding of each phase of the menstrual cycle.

This body-literate guide includes:

-40 nutrient-dense, menstrual-phase specific recipes that support overall health

-The science of menstrual cycles and how the different phases of the cycle affect the brain and body beyond the reproductive system

-How to track your cycle using fertility awareness-based methods

-How to prepare for and what to expect during the menopausal transition and beyond

-Detailed movement, self-care, and nutrition tips that support overall health throughout the menstrual cycle phases and your lifespan

Advance Praise for Cycles

Amy Hammer separates menstrual facts from fiction in a way that is both friendly and approachable. Packed with crucial information you may have missed in health class, Cycles gives you everything you need to reclaim and embrace all the seasons of your cycle.

—Amanda Laird, author of Heavy Flow: Breaking the Curse of Menstruation and host of the Heavy Flow Podcast.

For menstruators, learning about our biology and the intricacies of our menstrual cycle is a crucial part of unlearning the stigma we’ve lived through and the misinformation we've maybe been exposed to. Periods are powerful, and with a deeper understanding of our bodily changes, we can make informed decisions to maximize our energies and capabilities according to our menstrual cycles. I love that this book is one step to help do that!

—Nadya Okamoto author of Period Power


Amy J. Hammer has written a truly comprehensive and compassionate guide to reclaiming your menstrual cycle. Cycles provides women with a ton of insight into how their bodies work, and most importantly how to align their daily lives with their menstrual cycles. This is revolutionary information that will help women cultivate optimal health throughout their lives. Definitely one to have on your shelf!”

—Nicole Jardim, certified Women's Health Coach & author of Fix Your Period

In Cycles, Amy J. Hammer has written a remarkably thorough, comprehensive, and accessible guide to the reproductive and sexual health of humans who menstruate. She situates menstrual cycles in context of cycles of life and seasons of nature in a way that enhances our understanding of menstruation. The text presents a finely-tuned balance of the complexity and variety of individual cycles with commonalities across cycles and menstruators, with many helpful illustrations. Hammer explains medical terms for anatomy and for physiological processes clearly and concisely, without getting weighed down by jargon. Cycles can be read straight through or in sections of interest, then kept on the shelf as a reference for life.

—Elizabeth A. Kissling, Ph.D. Professor Emerita of Gender, Women’s, and Sexuality Studies, Eastern Washington University



Amy Hammer’s Cycles is a modern update to understanding our menstrual cycles. The blend of history with modern day science and thoughtful illustrations makes Cycles as interesting as a good novel.

—Halley Strongwater, clinical herbalist Loam Earth



Cycles is the book you always wish you had about your cycle that breaks down the science and history behind menstruation and beyond in an accessible, easy to digest way, while offering no-nonsense tips to improve not only your menstrual health, but overall health as well. After reading the book, it struck me just how little I knew about something I experience every month.”

—Auri Jackson, producer at Buzzfeed and writer, director and producer of The Spot