To get FDA approval, there must be clinical trials. But this is met with legal barriers.
Recreational use of medical marijuana is illegal in the United States; however, several states now allow its use for patients who are registered. What stands in the way?
The FDA requires the participation of hundreds to thousands of individuals in carefully conducted clinical trials in order to assess both the benefits and risks of the possible medication. To date, researchers have not been able to perform an adequate number of clinical trials on a large-scale level that prove the value of its medical potential (the benefits outweighing the risks).