Cortisol is needed in sufficient quanities, but too much of it will create problems. When you have prolonged stressors (such as infections or mental/emotional stress, or toxins) then you will develop problems either the adrenals will stop pumping out the cortisol (adrenal burn out, adrenal fatigue, Cushings') or if your adrenals can produce adequate cortisol and it continues to push out high amounts, the excess cortisol will begin devouring body tissue and nutrients this is called Catablic - whereas Anabolics will help restore the damage. Catabolic hormones are destructive over time.