The Flash Season 2: 11 Big Questions We're Asking After 'Trajectory'
5. Will Velocity-9 Be Used Again?
Don't do drugs, kids.
The Flash don't quite go that far with showing the negative effects of using Velocity-9, but they come pretty close, especially as Barry does the whole 'all the other kids are doing it' routine and contemplates taking the drug himself.
It's been tried out by both Jay Garrick and Trajectory, and both times it can be said it's failed, rather spectacularly in the latter's case. Still, it's a drug that can give people speed, or people with speed a boost, and there's always a chance it'll come back into play either later this year or in the future.