phytorelaxer - go or no go?

Well, i already have naturally straight hair, but i hear that phytorelaxer can soften hair so that it doesn't stick up on the top or stick out on the sides, AND that it can get rid of frizz. So two questions - can anybody confirm that this stuff really works? And also, since i have thick but reasonably soft hair, which phytorelaxer should i use - the one for fine hair, or the one for normal/thick/coarse hair? Thanks a plenty.