Which hormone helps to regulate metabolism?

The thyroid hormones are primarily responsible for regulating metabolism in the body. These hormones, primarily thyroxine (T4) and triiodothyronine (T3), are produced by the thyroid gland and play a crucial role in controlling the speed at which the body uses energy, processes nutrients, and maintains proper functioning of various organs. They influence several metabolic processes, including protein synthesis, oxygen consumption, and the overall metabolic rate.

When thyroid hormones are present in balanced amounts, they help ensure that the body's energy levels are optimized and that metabolic processes function efficiently. An underproduction of thyroid hormones can result in a slower metabolism, leading to weight gain and fatigue, while an overproduction can accelerate metabolism, potentially resulting in weight loss and increased energy levels.

Insulin primarily regulates blood glucose levels, cortisol is involved in stress response and metabolism of fats, proteins, and carbohydrates, and adrenaline plays a role in the body's fight-or-flight response. While all these hormones have metabolic effects, they do not primarily dictate metabolic rate in the way thyroid hormones do. Therefore, the correct answer highlights the central role of thyroid hormones in metabolic regulation.