Which hormone increases the metabolic rate of all cells?

Thyroxine, a hormone produced by the thyroid gland, plays a crucial role in regulating the body's metabolism. It increases the metabolic rate of virtually all cells by elevating oxygen consumption and stimulating the use of carbohydrates and fats for energy. When thyroxine levels rise, cells become more efficient in their metabolic processes, leading to an increase in energy expenditure. This is critical for maintaining body temperature, supporting growth and development, and ensuring that energy needs are met, especially during periods of increased physical activity.

In contrast, while insulin regulates glucose metabolism and can influence lipid storage, it does not directly increase the overall metabolic rate of all cells. Cortisol, a glucocorticoid hormone, can affect metabolism but primarily during stress and in response to low blood glucose levels, and it does not universally elevate metabolic rates. Estrogen has various roles in the body, particularly in reproductive health and secondary sexual characteristics, but it does not have a direct and consistent effect on metabolic rate across all cells like thyroxine does.