Like all hormones, cortisol is a chemical messenger. Produced by your adrenal glands, which are located on top of your kidneys, cortisol is produced during times of stress. Being stress hormones, many people want to know how to lower cortisol levels. But cortisol is often labelled purely as being bad however this is an oversimplification. You see, we need cortisol but high cortisol levels can be problematic. Can stress kill you?