Z-Mass is certainly not a miracle supplement.It is purported to increase levels of testosterone and growth hormone while you sleep.Perhaps if you are deficient in zinc,which is doubtful,you would raise your test levels somewhat.As for the growth hormone,it does contain a natural form of l-dopa which can raise GH a little.I took it for a while and it did help me sleep better for a while,but the effect wears off.Personally,I wouldn't bother with it...just my opinion.