Science
What is a hormone?
A hormone is a chemical messenger that travels through your blood to control body processes from a distance. Made by glands, hormones regulate growth, metabolism, mood, sleep, and much more by telling distant cells what to do.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains a hormone.
Key things to understand
- 1It's a chemical signal released into the bloodstream.
- 2Glands (like the thyroid and adrenal) produce them.
- 3They travel to distant organs and tell them how to act.
- 4They control growth, metabolism, mood, and reproduction.
- 5Tiny amounts can have powerful, body-wide effects.
Frequently asked questions
- What do hormones do?
- They act as chemical messengers carried in the blood, regulating processes like growth, metabolism, mood, sleep, and reproduction.
- Where are hormones made?
- By glands of the endocrine system, such as the thyroid, pancreas, adrenal glands, and pituitary.
- Why can small hormone changes have big effects?
- Hormones are extremely potent signals, so even tiny shifts can noticeably change energy, mood, growth, or body functions.