What is the difference between MDA and MDMA?
This article has been translated to English.
The difference is a single methyl group. MDA is MDMA without it, which sounds trivial and is not: MDA lasts longer, leans more psychedelic and less empathogenic, and is active at a lower dose, so a gram of one is not a gram of the other. MDA is also a metabolite of MDMA, which is part of why the effects overlap enough for people to confuse them.
Telling them apart with reagents
Simon's reagent is the one that separates them, and it does it by a quirk of chemistry rather than by recognising either compound. Simon's reacts with secondary amines and turns deep blue; MDMA is a secondary amine and MDA is a primary one, so MDMA turns Simon's blue and MDA does not. Robadope does the mirror image, reacting with primary amines, so MDA turns Robadope pink or purple while MDMA leaves it alone. Run both and the pair of results tells you which you have, where either one alone leaves you guessing.
The table below sets the MDMA colour against the MDA colour for each reagent.
| Reagent | MDMA | MDA |
|---|---|---|
| Marquis | purple to black | purple to black |
| Mecke | blue to black | blue to black |
| Simon's | deep blue | no change |
| Robadope | no change | pink or purple |
Marquis and Mecke are nearly identical for the two, which is exactly why a kit with only those two cannot answer this question.
Why it matters for dose
MDA is generally taken at a lower dose than MDMA and runs longer, so somebody who redoses on an MDA schedule learned from MDMA is stacking a longer-acting compound. Neither reagent result tells you how much you have, which is a separate test: for a pressed pill the mg figure comes from the alerts database if the press has been tested, and for powder it comes from a quantity or TLC test.
The table below sets the oral figures side by side: threshold, common and strong doses, and how long each one lasts.
| Compound | Threshold | Common | Strong | Total duration |
|---|---|---|---|---|
| MDMA | 35 mg | 75-125 mg | 125-175 mg | 4-6 h |
| MDA | 20 mg | 75-125 mg | from 125 mg | 4-8 h |
Sources: dose figures come from our substance library, which aggregates dose.wiki, PsychonautWiki, TripSit and Erowid. Treat them as approximate.
What the labs see
MDA on its own is uncommon in the published European samples, which is worth knowing when you are told a pill is "MDA rather than MDMA". Far more often what turns up is MDMA, sometimes alongside something else. If somebody is selling MDA as a premium alternative, the reagent pair above is a two minute check on that claim.
Questions?
Is MDA stronger than MDMA?
Active at a lower dose and longer lasting, which is not the same as stronger. Treat the dose you know for one as no guide to the other.
Will Marquis tell them apart?
No. Both go purple to black. You need Simon's and Robadope.
Is MDA a metabolite of MDMA?
Yes, which is part of why the subjective effects overlap.
What if Simon's and Robadope both react?
That indicates both a primary and a secondary amine are present, so a mixture rather than one compound. A TLC test will show you how many things are in there.
No test result can tell you a substance is safe. No substance is 100% safe.This article is published for harm reduction purposes. It does not encourage the use of psychoactive substances and does not replace medical advice.