Stardust is a free cycle tracking app that integrates science, ancient wisdom, astronomy, and artificial intelligence to help users understand and work with their hormones, track their menstrual cycle, and sync their cycles with friends. The app provides personalized trends and insights about the user's cycle, as well as information on hormones such as follicle-stimulating hormone (FSH), testosterone, estrogen, luteinizing hormone (LH), and progesterone. It also explores the folklore and magic of menstrual-lunar synchronicity.