The alkaloids are the "active" part that actually does something. Ephedra is a herb, and not all parts of the plant are "active" so when you have Xmg of Ephedra, only a certain percent will be Ephedra alkaloids. As a side note, that is a very high dose of alkaloids if I'm not mistaken. Xenadrine (the real ****) had like 20mg per servering with 200mg caffine and 20mg asprin equivalent and that stuff gets me pretty wired to this day.
ManBeast