I read somewhere recently that the effectiveness of a receptor site to AS is directly related to the amount of the mineral, zinc, in the receptor itself. Apparently, use of AS uses up zinc stores at a high rate, and that has a lot to do with how AS quickly becomes less effective over the length of a cycle. The problem is, I can't remember where the hell I read this info, has anyone else seen anything along these lines? That would be pretty sweet if we could prolong the length of cycles by supplementing zinc.....I just bought some, $5 for a month's supply!