Oh wow. I saw the title and was ready to explain how the cartels had perfected p2p synths such that they yield almost exclusively pure d-methamphetamine, but before explaining that I was going to need to explain the general concept of chirality and enantiomers, and the fact that for amphetamines (especially meth) the d-entantiomer is always the "one you want" and the l-entantiomer is always the less desirable, less powerful form that causes peripheral stimulation but no cerebral effects, and as an anecdote I was going to mention that vics vapo inhaler (commonly used at raves, although people don't actually know what they're inhaling) is levomethamphetamine, and I was even going to mention the humorous fact that they label it "levmetamfetamine" to make the spelling as distinct as possible.

Then imagine my surprise when I open the article and it literally covers every one of those points, section by section. Brilliant.

I guess the only minor thing I'd add is that the way the cartels (and others) are getting pure d-meth is by bubbling through d-tartaric acid or the like at the end of the process, which separates the racemic meth into its l and d enantiomers respectively.

I'm glad this article debunked the fallacious "new meth" article that cropped up here the other day.

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EDIT:

Oh and one more thing. There's a common myth among tweakers about "n-iso", which is structurally very similar to methamphetamine - similar enough that it will join the crystal lattice - but it is at best inert, but might actually cause undesirable side effects. The fact that n-iso exists is real, but if you look online you'll see tons of tweakers convinced that they've been smoking n-iso and that it's why they smoke meth and just get a headache and other bad physical side effects but don't get the stimulation or the pleasurable rush. What's actually happening is that they've spiked their tolerance so high that they're getting almost exclusively the bad effects. It's analogous to how if someone takes MDMA for 4 days straight, by the end of it they're not going to "roll" at all because they've acutely downregulated their serotonin (and dopamine) receptors, and furthermore that they've literally (almost) exhausted their current pool of neurotransmitters, which need to be re-synthesized by the body.

When looking at the DEA seizure data it's clear that meth is one of the most pure and potent (wrt methamphetamine, the dea defines purity as what % of the compound is meth, meaning either levo or dextro methamphetamine, whereas potency only factors in the d-meth content, since d-meth is the enantiomer that actually gets you cerebrally high) street drugs out there. By comparison, cocaine is one of the most disgusting, cut at the source level with stuff like levamisole (which is thought to be disastrous to health, ie it's not just inert), and then further cut every step down the chain, albeit usually with inert cuts (baby powder, baking soda, glucose, creatine, that kinda stuff) the lower down the chain you get. Seriously kids, don't do cocaine. It's overhyped and a waste of money.

So anyway, as I said two paragraphs above, n-iso is real but the idea that there's tons of n-iso crystal floating around is just an urban legend promulgated by tweakers who spiked their tolerance the moon and refuse to see that fact.