Caffeine is nasty, barely drank it over the last 15 years.

I tend to find enough stimulation from the B5 and B3; flushing Niacin is great. I get jittery when I take a B-Complex regularly (currently have Jarrow's B Right - it's like rocket fuel for me), most likely methylation issues.

I sometimes take L-Tyrosine or L-Phenylalanine if I'm feeling a bit low on Dopamine - both of those are stimulatory and can also raise adrenaline (while 500mg of DLPA is on another level - great for intense workouts, BUT definitely not a PM supplement!)