So they put GABA inside it, which is too big a molecule to cross the blood-brain barrier and therefore has zero effect on anxiety and stress. Useless, unless you want a growth hormone for building muscle mass or you don't actually have a blood-brain barrier (chances are you do, however).
They use passionflower, valerian and kava-kava which are very mild anxiolytics and they top it off with a dopamine precursor which is exactly what you don't need for anxiety inhibition. Kinda like a speedball. Maybe they should add some caffeine and xanax in there to increase the potency.
Bottom line, I never tried serelax but it looks like utter BS.
I'd use passionflower or kava-kava alone for anxiety. Problem is, they are extremely mild and you build tolerance very quickly but you have nothing to lose and they'll definitely come cheaper.