BBC news about Smart drugs and amazing infographic
The growing use of so-called smart drugs is a concern, government health advisers have said.
The Home Office has told Newsbeat the Advisory Council on the Misuse of Drugs is to carry out a review of their use.
Some users of the drugs, which are legitimately prescribed for brain disorders, say they can help them stay awake longer so they can study.
Health experts say side effects can include psychiatric symptoms, prolonged anxiety and digestive problems.