I use flux as well. I still don't get tired at night (not if I'm working on something remotely interesting...), but it does seem to help me "settle down" a bit

I use flux as well. I still don't get tired at night (not if I'm working on something remotely interesting...), but it does seem to help me "settle down" a bit at night, so when I decide it's time to pack up for the day, I can often be asleep within 10 minutes (this used to be harder for me).