Hormones rule the lives of all humans – not just women. They are the chemical messengers, secreted by the glands in your body, which travel through your bloodstream to their target organs and tissues, giving instruction on processes that need to be carried out in order to regulate your health and behaviour. When you feel hangry (hungry and angry) they tell you that you need to eat something, when you’re stressed they get your blood pumping so that you can put up a fight or do a runner, and at the end of the day they let you know that it’s time to go to bed. They also control your menstrual cycles and cause or contribute towards the variations in energy, mood, sexual desire, and changes to your body and behaviour that you experience as you transition through each menstrual cycle.