Examine.com is your friend. Unfortunately they went through a site redesign recently that puts their most powerful organizational tools behind a paywall. Then again, they need to earn their $ and their services are well worth it.

http://examine.com/supplements/Hibiscus+sabdariffa/#summary4...

Also cut all caffeine from your diet. :) (Also the #1 recommendation when people come over to /r/nootropics and ask for help with anxiety!)

Wow, thanks for the tips! I'm not sure how feasible cutting out caffeine would be though :-(

The withdrawal is painful, but at the end of the day, a regular caffeine habit doesn't really help with wakefulness that much.

If you just use it occasionally when it is really needed you will get a much bigger boost from it.