I notice you didn't include anti-oxidants in your list of things it is impossible to test, because of the mounting evidence that they A) do nothing and B) have

I notice you didn't include anti-oxidants in your list of things it is impossible to test, because of the mounting evidence that they A) do nothing and B) have a plausible mechanism to be harmful. It's not Pharma or the FDA. Why would a company selling garlic extract want to run a trial to prove that their one product doesn't work? The number of people using it would probably barely increase if the result is positive, and if the result is negative they will go out of business.