Impure/crap MDMA is a scourge. It is extremely common, esp. state-side. Some mandy tablets don't even have anything related to MDA, MDMA etc. This is why you should ideally purchase drug testing kits, especially if you buy from the street instead of SR. In my opinion, this is why more people are buying power over pills today.The science studies really are correct, tolerance issues aside (you drug-pig fiends! lol), 100mg - 200mg is more than enough for most people. This is why SR is a huge blessing for party goers everywhere, you actually have a fair idea of what quantities you've taken. If not, the feedback would very quickly tell you otherwise. People aren't stupid, they don't need a degree in organic chemistry to know they've had a bad time or a good time.This is why I like SR, it provides an environment in which customer and seller can transact without the high drama/soap opera element. I think some people might actually like this at the beginning (oooh, so taboo), but trust me, it gets pretty fucking wearisome after a while.Anyway yeah, lower your dose, protect your wallet. It's just like your momma told you with cooking sauces 'you can always add more', so start with 100mg and then use your judgement to up the dose.Note: Erowid and the DEA agree that the half life of MDMA is 8-9 hours (+/- 2 hours). Frequently people have 1 dose and then have another later. So if 100mg is doing the job for you, you can sustain that by putting your mobile onto a timer for six or seven hours time. However, a lull is likely to occur before the half-life.I know not everybody is like me, but I like to be scientific about these things, I think everybody should be using the kits, mg scales etc as a matter of principal. I cannot for the life of me understand why people pop Rx pills like so many M&Ms into their mouths because the doctor gave them and gave the thumbs up. Do you know that more people accidentally overdose from anti-depressants, aspirin and paracetamol than scheduled substances? You know why? Because they don't take them seriously and imagine they can take them whenever they want, as much as they want.The most bizarre fact about the Drug War, is that a vehemently anti-drug legalization/decriminalization Rx toting granny, is more likely to OD on legal drugs, than her more socially liberal grandchildren on illegal ones.Actually, I take that back, many grannies are more liberal than their stuck-up grandchildren since they remember when many scheduled drugs were legal, but the point remains the same.