Hormones are secreted by the endocrine system or cells with endocrine functions, and hormones can act either on other parts of the body or on the endocrine system itself. Hormones are substances secreted by the body’s endocrine glands or endocrine cells that are biologically active and act as messengers to transmit information. Their main components are peptides, amino acids, and steroids. The endocrine system is composed of the hypothalamus, pituitary gland, thyroid gland, thymus gland, adrenal glands, gonads (ovaries, testes), and gastrointestinal endocrine cells, which secrete various hormones. After being secreted by the endocrine system, hormones are usually diffused into the bloodstream and transported to other tissues throughout the body to exert their physiological effects, either on other systems or on the endocrine system itself, stimulating the endocrine system to secrete other hormones. If you have any other questions, we recommend that you seek medical advice.