"In the past 30 years or so, bioethical control of medical research on humans has transitioned significantly. Intense federal regulation of clinical trials makes it hard to believe that abuses of the past could be repeated."
On the contrary it makes it hard to believe that no one would ever abuse the system again.
"Does a purveyor of alternative/natural products perform any sort of documented long term research on human subjects for efficacy and safety? Do they collect and react to information about adverse effects? "
Yes absolutely they do. Not only that but there is thousands of years of natural medicine documentation.