MD-6 used to contain norephedrine. The formula was changed sometime ago and it now contains, I believe, ephedra, caffein, yohimbine HCL, ALA, and 5-htp. Only Biotest is stupid enough to market a combination ephedra/yohimbine formula. SOme tolerate taking yohimbine and ephedra together, but for other it can cause dangerous elevations in blood pressure and/or heart rate. Adipokinetix, which like the old MD-6 is a norephedrine/yohimbine/caffeine stack, is at this point near impossible to find--as are all products containing norephedrine. I recently scoured the net trying to find a norephedrine/yohimbine stack and my only luck was ordering directly from SAN, which is selling its remaining stock of 'Hollywood Cuts' direct from their site(It's basically an identical formula to Adipokinetix.)