Dosage depends on a variety of factors including; age, weight, individual biology, conditions you wish to address and other medications you maybe taking.  Ultimately it depends on the goal an individual wishes to address.  It is recommended to start off with a low dose and gradually increase as needed.  There are no known adverse effects of over dosage and no known over doses with CBD, according to the World Health Organization in 2017. We put together a chart as a reference and a starting point linked HERE.