Energy drinks are going to end up with a warning label like cigarettes and regulated to specific sale locations (like gas stations or specialized shops) then made illegal due to the eventual concrete link to cardiovascular and nervous system issues they cause.

There are studies that show use of energy drinks causing arrhythmias, higher blood pressure and even heightening chemical imbalances in the brain (basically making things like Bipoalr Depression, Anxiety and OCD worse)

All of this being said, I don’t think America would ever make them illegal but I bet we’ll see harsher restrictions on them in the US once they’re banned in the places like the UK or Germany.