A hormone is a chemical messenger produced by glands in the body that helps regulate various functions. These substances travel through the bloodstream to target organs, influencing processes like growth, metabolism, and mood. For example, the thyroid hormone plays a crucial role in controlling how the body uses energy. Hormones are essential for maintaining balance in the body, often referred to as homeostasis. They can affect everything from sleep patterns to reproductive health. When hormone levels are out of balance, it can lead to various health issues, highlighting the importance of these tiny but powerful molecules in our daily lives.