From back in the day, I remember that MDMA was an analog of other meth type drugs, and that shortly after it hit the mainstream in the 80's, it was made illegal and congress passed the Federal Analog Act:
Federal Analog Act - Wikipedia, the free encyclopedia
Which basically made any drug that is 'substantially' similar to an existing schedule I or II drug illegal to sell or possess. Now obviously, slapping a methyl group to an existing drug and then selling it, creates a drug that is substantially similar to it's already illegal counterpart, with similar results. And even by a conservative definition, there are measurable effects on a person's CNS. However, some interpretations have it that simply by having a chemical structure very similar to an already existing controlled substance, it has already met the criteria imposed by the law. So, how in the world, are companies able to sell methylated masteron to people in the United States?