Cortisol is a steroid hormone produced by the adrenal glands of the body. It belongs to a group of glucocorticoid hormones which are mostly involved in the metabolism of carbohydrates and fat proteins, as other activities such as inhibition of inflammatory reactions. It plays an important role in bone growth, regulation of blood pressure and cardiovascular function, immune system function, metabolism of fats, carbohydrates, proteins and stress response. Too much or too little cortisol in the body can cause a number of problems including weight gain, excessive fatigue, changes in mood, depression, infertility and impairment in cognitive function.