Notes on amphetamines

Methamphetamine is one specific organic molecule, amphetamine is another specific organic molecule. The effects of the two are very similar, but the difference is easily noticeable if you do both of them on various occasions. The differences are probably mostly due to different time-course of activity (meth lasts longer) and different ratios of activity on the serotonin, dopamine and norepinephrine systems.*

It is probably usually possible to tell the difference between the high of methamphetamine and amphetamine, all other things being equal, and possibly even all other things not being equal.

As others have mentioned, the quality of street drugs is very variable. I have heard there's a big difference in experience between crappy street meth and good street meth, and also a big difference in experience between good street meth and pharmaceutical-grade meth. In principle it is not all that hard for unofficial chemists to make extremely high quality products that should be essentially equivalent to pharmaceutical grade, but I suspect this doesn't happen very often. So most users can probably tell the difference between different levels of quality if they pay attention. In some cases it might be a big difference; I suspect that in some cases, the impurities in street meth make the high much more jittery and aggressive. The infamous usenet chemist POPi once wrote a bizarre, semi-coded message about the chemistry and subjective effects of various impurities, including ASCII art of anatomically-correct stick figures representing the different molecules and isomers. It was something to behold, that's for sure.

As a totally separate question, methamphetamine or amphetamine or most other drugs are usually used in the form called the "salt", as opposed to the "free base". The organic molecule by itself is the free base, since it is basic i.e. alkaline. (This is true for a whole class of nitrogen-containing organic molecules called alkaloids, which includes most, but not all, psychoactive drugs.) Some of these free base forms are liquid or non-water-soluble solids. Methamphetamine, amphetamine and MDMA are non-water-soluble liquids in free base form, so all of them are commonly formed into a salt by reacting with some kind of acid (not the drug). The most common acids would be hydrochloric acid (HCl) or sulfuric acid (H2SO4) but others will be used in various cases due to availability or other idiosyncratic reasons. So, for example, most of the prescription amphetamine is in the form of the sulfate (i.e. the salt with sulfuric acid.) Most street meth or amphetamine or MDMA will probably be the HCl salt (which would usually be called the hydrochloride).

When an alkaloid salt is dissolved in water, the alkaloid part disassociates from the acid part. This means that by the time it reaches your brain it doesn't matter what salt it was. However, the different salts might have different flavor or "burn" when snorted. So the average user might be able to tell different salts apart by the taste or feel, but almost certainly not from the high.

The most complicated factor is the stereoisomer. Anything with the amphetamine structure (including MDMA and all the psychedelic amphetamines Shulgin was so fond of) has one particular carbon atom around which the structure can be arranged in two different ways which are mirror images of each other. For methamphetamine, amphetamine, and MDMA only the one called d or R (the other is called l or S) is active. The S isomer has some activity, but it is much, much weaker (possibly as much as 20-100 times weaker) and the effect is generally more like "minor jitteriness and irritability" than like the high people would want.

The really unusual thing is that despite the apparent poor activity of the S isomers, there is some reason to believe that mixing the S isomer with the R isomer improves the quality above the R isomer alone. I have seen various mentions of this, in PIHKAL regarding MDMA, and other places I can't remember, but most notably, the prescription drug Adderall contains a specific mixture of isomers for reasons I don't really know. It is possible that they have some good reason for it, though.

Depending on how an amphetamine-type drug is synthesized, it will usually be either the active d-form alone, or an equal mixture of the two forms. The mixture is called a racemate, or a racemic mixture. Meth made from ephedrine or pseudoephedrine will be the d-form alone, because naturally occuring ephedrine is the d-form alone. Meth made from phenylacetone, like the Hell's Angels used to do it, will be the racemate. I don't know much about the subjective difference, but I have heard unreliable rumors that the racemate is a better high than the d-form alone.

* According to the current research, methamphetamine releases norepinephrine, dopamine, and serotonin in the ratio 1:2:60 by reversing the transporters. The current literature also says that MDMA does essentially exactly the same thing, with perhaps minor differences in the ratio. This pretty much proves that the current literature has no idea what produces the subjective effects, since the effects of MDMA are *very* different from the effects of meth!

You can read the old POPi message from alt.drugs.chemistry on March 5, 1996 at 2:00 AM at the link to Google Groups. Warning: severe old-skool drug geekery ahead!

Note that you might want to copy and paste the text into something with a fixed-width font to be able to appreciate the ASCII art. For some reason, despite having so many smart people, Google is too stupid to realize that the entire universe of Usenet they bought a few years ago was all intended to show up in fixed fonts...