Hormones have the following effects on the body:
* stimulation or inhibition of growth
* wake-sleep cycle and other circadian rhythms
* mood swings
* induction or suppression of apoptosis (programmed cell death)
* activation or inhibition of the immune system
* regulation of metabolism
* preparation of the body for mating, fighting, fleeing, and other activity
* preparation of the body for a new phase of life, such as puberty, parenting, and menopause
* control of the reproductive cycle
* hunger cravings
A hormone may also regulate the production and release of other hormones. Hormone signals control the internal environment of the body through homeostasis.