How pure is methamphetamine?

This article has been translated to English.

Methamphetamine is consistently very pure in the published European samples, and far more consistent than amphetamine. Across 43 samples where methamphetamine was the main compound, the middle half sat between 90% and 98%. Across 436 amphetamine samples, the middle half ran all the way from 14% to 89%.

Only 14 of the meth samples carried a purity number, which is normal enough: a lab has little to report when a sample is essentially one compound. Both columns also cover only samples a lab confirmed contained that compound, so they describe a market. What is in your bag is a question for a test kit.

That is a reason to test more carefully rather than less. The two are sold as each other routinely and look identical as a white powder, and methamphetamine is both purer and active at lower doses: our substance library puts a common oral dose of amphetamine at 15 to 30 mg against 10 to 25 mg for methamphetamine. Mixing them up is not a small error in either direction.

The table below compares the two on the same basis, with the sample count behind each purity figure.

Amphetamine and methamphetamine compared on the same basis: samples, purity and adulteration

	Amphetamine	Methamphetamine
Samples	436	43
With a purity figure	204	14
Median purity	58%	95%
Middle half	14% to 89%	90% to 98%
With a second compound	86%	16%

A white powder gives you no way to tell which column you are holding. That is what the Simon's reagent is for, and it takes a minute.

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Telling it from amphetamine

Simon's is the reagent that does it. Methamphetamine is a secondary amine and turns Simon's deep blue; amphetamine is a primary amine and does not react, turning Robadope pink or purple instead. Marquis gives a similar orange to brown for both, so a kit without Simon's cannot answer this question, and the substitution matters because the two have different durations and different redose behaviour.

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When it is cut, and with what

Rarely, and with caffeine, cathinones or MDMA when it happens. One sample in the set contained ethylbromazolam, a designer benzodiazepine, which is an unusual thing to find in a stimulant and the sort of result that only shows up because somebody sent it to a lab.

Questions?

If meth is usually pure, why test it?

Because those figures come from samples a lab had already identified, and because the two are sold as each other routinely. Through the middle half of the samples amphetamine ran from 14% to 89% and methamphetamine from 90% to 98%, so guessing wrong about which one you have can change the dose by more than half. Simon's settles it in a minute.

How do I tell meth from speed?

Simon's reagent. Blue for methamphetamine, no reaction for amphetamine.

Why does high purity matter?

Because a dose worked out on 58% material is a different dose on 95% material, and nothing about the powder tells you which you have. Methamphetamine is also active at lower doses than amphetamine, so the two errors stack. That makes it an identity question before it is a purity one, which is a reagent rather than a testing card.

Does Marquis separate them?

No, both give a similar orange to brown result. Simon's is the one that separates them, blue for methamphetamine and no reaction for amphetamine, which is why the two reagents are sold together.