How do hormones regulate biological processes?

 Hormones are molecules that act as chemical messengers in the body’s endocrine system. They regulate various biological activities including growth, development, reproduction, energy use and storage, and water and electrolyte balance. Hormones are produced by certain organs and glands and are secreted into the blood or other bodily fluids. They carry chemical messages from the glands where they are produced to cells in different parts of the human body. These chemical messages help to turn on or turn off cellular processes that control stress, appetite, growth, sleep cycles, blood sugar, sex drive, and sexual function.