Most commercial meth on the streets of America today is enantiomeric--meaning it is a mixture of 50% dextro-methamphetamine hydrochloride and 50% levo-methamphetamine hydrochloride. The levo portion is basically inactive and can be had over the counter in Vick's brand nasal inhalers. Levo meth may interact and or interfere with the effects of dextro meth. Racemic methamphetamine is produced when P2P is used as the chemical precursor, for example. If pure, extracted ma huang ephedra ephedrine is used as the chemical precursor, then 100% dextro methamphetamine will result. The pure, recrstallized hydrochloride salt of this substance is legally defined as ICE methamphetamine in the United States and carries with it much stiffer criminal penalties. Ice methamphetamine was more prevalent on the street level around 2000. The longest I stayed awake on it was 6 days with 1.75 grams. The longest I stayed awake on the more recent racemic 'ice' was 3 days with over an eight ball. I now just stick with my legal ADHD medicine. I haven't had a truly good roll or MDMA pill since 2003, I'd say, and have given up on 'ecstasy' for the time being. Prescription methamphetamine is the sulfate salt and is comparable though not really superior to street meth. Meth is hard to find in the North East. Internet drug nerds often insist that ICE refers to 4-methylaminorex, and it can, but usually not.