What is cortisol known to be?

Cortisol is widely recognized as a hormone that is released during times of stress. It is produced by the adrenal glands and plays a crucial role in the body's "fight or flight" response. When an individual faces a stressful situation, cortisol is secreted to help manage and cope with that stress. It aids in increasing blood sugar levels, suppressing the immune system’s response, and regulating metabolism—all of which are essential for helping the body respond to danger effectively. The presence of cortisol allows for enhanced alertness and energy, enabling an individual to deal with immediate challenges.

The other options focus on different biological functions that do not accurately describe cortisol’s primary role. For instance, neurotransmitters, which are involved in mood regulation, are different from hormones like cortisol. Similarly, proteins and vitamins have distinct functions that do not relate directly to cortisol's role in stress response. Thus, the identification of cortisol as a stress-related hormone is essential for understanding its impact on both psychological and physiological processes in the body.