Hormones are chemical messengers secreted by endocrine glands that regulate various physiological processes, such as growth, metabolism, reproduction, and mood. For example, insulin controls blood sugar levels, while thyroid hormones regulate metabolism. Hormonal imbalances, such as excess cortisol in Cushing's syndrome or insufficient insulin in diabetes, can disrupt normal functioning, leading to chronic conditions. Proper diagnosis, medication, and lifestyle changes can help restore hormonal balance and improve health outcomes.