Absolutely. If you're looking for examples of things going wrong, the researchchemicals forum unfortunately has more than a few cases of people showing symptoms

Absolutely. If you're looking for examples of things going wrong, the researchchemicals forum unfortunately has more than a few cases of people showing symptoms of serious nerve damage after experimenting with NPS ('novel psychoactive substances') stimulants ordered from RC vendors. That is despite a (smaller) subset of them being careful and methodical with dosage. Personally, as a very squeamish person, I'm more than happy to stick with the tried and true, and in desperately boring moderate amounts :)