^With magnesium it may help keep tolerance from building, but more importantly I have found that opiates just don't work that well if I am deficient in magnesium. Being a daily heroin heroin (aka junkie) I have found it is the absolutely necessary to make sure I get the most bang for my buck. I actually ran out of mag supplements on Monday, so didn' take any on Tuesday, which was not a big deal b/c I had taken a good amount on Monday. But on yesterday I noticed I was not getting very high at all from my first 2 doses of the day, and my 2nd dose was a pretty good sized one. Noticing this, first thing I thought was the stuff was bunk, which seemed odd b/c it looked identical to my last bags and they were good. Then I though about not having taken a Mg sup recently, so I ran to GNC and grabbed some Mag Ox (would of liked Citrate or Stearate but unbelievably GNC had neither, the guy working there even said someone had just came in looking for Mag Citrate, as well). I went straight home, ate a decent meal and popped a few of those along with the meal. Waited an hour and then dosed up again. Surprise, I was nice and high, much higher than earlier off less than I used earlier. IMO Mg is an absolute must for anyone using opiates regularly.