Impartial sources are hard to find
Medical journals have been called "an extension of the marketing arm of pharmaceutical companies", because industry funding can affect a study’s results and/or the way those results are presented in the paper. When a paper with favourable results manages to pass through peer-review and get published in a major journal it is "worth thousands of pages of advertising." That is, first, because people who aren’t that affected by commercials (say, your doctor) take trials published by a major journal much more seriously . If the media pick up the paper as well, the pharmaceutical company can enjoy further advertising, this time straight to the general public.