Hi,
I wonder what is the role of Beta Alanine as a pre workout. As far as I understand it, it act in the long term by producing Carnosine so the immediate effects are irrelevant. But I see that so many pre workouts has Beta Alanine in them, so I wonder if there’s any immediate benefit in performance after taking it?
And a side question - which supplements (legal ones) improve performance right after taking them except of Caffeine?
Thanks! 
While I think beta alanine has reasonably good evidence for increasing the amount of training people can do (and subsequently results), plus likely some stamina benefit, I am not sure it needs to be dosed before and after a workout for it to work. That said, most of the studies showing a benefit investigate it like this. We could say the same of creatine re: immediacy of benefit.
I don’t think there are many supplements that reliably increase performance in the short-term, but I’d be thinking caffeine, sodium bicarbonate, and a nitrate supplement.
But with creatine, like beta alanine, your position as of right now that it needs to be taken whenever during the day, right?
Thanks 
Yes, that’s exactly right!