The hormone responsible for regulating metabolism is thyroid hormone, primarily produced by the thyroid gland. Thyroid hormones, including thyroxine (T4) and triiodothyronine (T3), play crucial roles in various bodily functions, such as metabolism, energy production, and growth. They influence how the body uses energy from food and how it interacts with nutrients. When thyroid hormone levels are balanced, metabolism operates efficiently, but imbalances can lead to conditions like hyperthyroidism (excess hormone production) or hypothyroidism (insufficient hormone production), both of which significantly affect metabolic processes and overall health.