Opinions - MDMA safety

[Madcow]

Recently, SWIM had a troubling MDMA experience. In the beginning of said experience, he was sweating profusely with fairly shallow breathing, and a hint of MDMA in the mix of effects. After a while these tapered off and left a decent roll for a few more hours.

Now, these pills have had mixed reviews. A couple of SWIM's friends had the same ones, but they had good experiences (mind you none of them have had previous MDMA experience). But, SWIM's brother, who also had not previously had experience, reported effects similar to SWIM. PillReports has a few reports on these particular pills in his area and say they're high MDMA content. There were people who commented on these and said that there were good effects. The reagent test came out purple.

What is the possibility of the pills containing a product of improper synthesis such as MDEA, or are the chances higher for having been cut with something strong enough to ruin the beginning of SWIM's experience? Or is the possibility of having built a tolerance plausible even though SWIM has used MDMA less than even 10 times?