I don't know about the SERT density.

This isn't my trial, but i went through the same steps with beta-cit before my scans - injections, blood work, they watched me carefully, making sure there were no adverse events.

And as has been said over and over - it's an individual decision whether to participate in clinical trials or not. But for every treatment we use today, humans signed up, took their chances, and were experimented on. It's the only way we get new treatments.