Hormones are chemical substances having a specific regulatory effect on the activity of a certain organ or organs, especially substances secreted by various endocrine glands and transported in the bloodstream to the target organs. Hormones are your body's chemical messengers that travel in your bloodstream to tissues or organs. They affect the body's processes such as growth and development, metabolism, sexual function, reproduction, and mood. Hormones are produced by endocrine glands. The major endocrine glands are the pituitary, pineal, thymus, thyroid, adrenal glands and pancreas. Men will produce also hormones within the testes and women produce hormones in the ovaries. Hormone balance is regulated by the pituitary. Tiny shifts cause large changes to cells or throughout the entire body. Hormone levels are measured in your blood, urine or saliva.