If you could try one drug without getting arrested and have no negative effects what would it be?
There is no drug you can try and fail to have negative effects. For each drug, you will have side effects even though it will be mild. On the other hand, one would get arrested if they are not of age or if the drug is illegal according to the law.
To the best of my knowledge, there is no "drug" that doesn't have negative effects, including side effects.
Depends on your definition of negative effects. And there's no such thing as 'side' effects , there's only effects.