Been using GlycerGrow for about 3 weeks.
It's not the holy grail, that's for sure.
But it does work very well with pumps, and muscle fullness.
I beleive the main ingredient is GMS, but it also has L-taurine and Electrolytes in the mix.
It has more than enough servings to last you 5 months, if you take it pre-workout only.
Just make sure to drink about 1-2 gallons of water on it, otherwise you will dehydrate.