What is the main function of proteins besides building tissue?

Proteins play several critical roles in the body beyond merely aiding in tissue building. One of the primary functions of proteins is indeed related to hormonal regulation. Hormones are biochemical messengers that help regulate various physiological processes, and many of them are proteins or peptides that facilitate communication within the body.

Additionally, proteins can serve as an energy source, although this is not their main role. When carbohydrates and fats are in short supply, the body can utilize amino acids from proteins to generate energy.

Moreover, proteins are essential for a strong immune response. Antibodies, which are crucial components of the immune system, are proteins that help identify and neutralize pathogens like bacteria and viruses.

Overall, proteins are extremely versatile and play multiple vital roles in the body, such as regulating hormones, providing energy when needed, and boosting immune function, making "all of the above" the most comprehensive answer.