So, what is cortisol and why is it so important? Many people think of cortisol as just the “stress hormone”, but that is not its main role in the human body. Cortisol is primarily the body’s protective mechanism to keep your glucose levels from dropping dangerously low, preventing you from going into a hypoglycemic coma and dying. It does this by breaking down lean muscle, bones and brain tissue into amino acids that your liver can then convert into glucose.