Health research is difficult for a bunch of reasons. One of those reasons is the practice of using lawsuits to stifle research. A researcher finds that a product is harmful, and the producers of that product attack the researcher in court, in an attempt to discredit the scientists, stop the research, and protect profits. This has happened with lead, it’s happened with guns, and it has happened with synthetic amphetamines in dietary supplements. Unbelievable, but true.