^ The majority of studies saying lower doses are not damaging are only talking about a SINGLE dose... not everyday use over an extended period of time.
if it's simple serotonergic action that is causing the upregulation than surely there are MUCH safer alternatives
Can you link a study that's administered like 20-40mg MDMA? I've never even seen one.
This is the theory, which appear's to suggest that it's MDMA's specific mechanism of serotonin release that would have the potential to stimulate neuronal growth. If it was just increasing serotonin then I agree that other drugs could be a better option. But it could be the actual mechanism by which serotonin is released that is also important. Further, there isn't a drug, known to man, that is able to selectively release serotonin like MDMA does. M-CAT causes comparable release but is far less selective to serotonin, instead imposing further actions on dopamine. Perhaps methylone could be an option? I don't really know how methylone works.MDMA’s release of serotonin modulates receptor enzymes and stimulates astrocytes to release Neurotrophic Growth Factors (NGF)
I'm not convinced that there are other alternatives. MDMA is such a unique drug.