[code_reuse]

You were under a false impression if you're referring to a single recreational dose (approx 120mg) taken once or even twice a weekend. The studies on animals that are often pointed to in Wikipedia involve exposing lab animals to doses that are both quite high and importantly far more frequent than the way this drug would utilized during sessions or as a party drug. Controlled tests on lab animals where a more normal dose was given and a more appropriate period of time was given between the next dose do not show any compelling evidence of any kind of long-term anomalies.

The studies on humans that are often cited are typically unscientific because they're inclusive of individuals who also use other substances that are known to be neurotoxic such as alcohol or even methamphetamine. Also more importantly these recreational users are not given a supply of pure MDMA so it's safe to assume that some percentage of them are actually ingesting a cocktail of MDMA adulterated with other substances.

With all of this said, the verdict is still out on whether or not this is neurotoxic in human at normal doses.. there definitely is a long term tolerance that builds up to the effect of the drug but this alone does not prove anything about neurotoxicity.