I edited my comment to be more neutral towards Methamphetamine; I wasn't aware of the significant dosing differences and that's important. The real problem is

I edited my comment to be more neutral towards Methamphetamine; I wasn't aware of the significant dosing differences and that's important. The real problem is the way the studies were conducted. They didn't test hair samples to verify whether the participants used MDMA, much less control the environment it was taken in. The largest study I referred to that was done by Harvard Medical was done on people who had never tried the drug before, were not at raves taking drugs which could not be verified for purity (amongst other problems like dehydration and hyperthermia), and they verified their study through hair samples.