[jwbwater]

A plausible mechanism of action is no where near good enough. Molecular biology is crazy complicated and lots of things that sound plausible don't work (and maybe do the opposite). I'll take "it works, but we don't know why" over "this is why we think it might work" every time.

[ksaj]

There are actually a number of drugs where they specifically state the actual mechanism of action is unknown, but they do know from proper and continued clinical trials that the drug does indeed work. A lot of pain killers are in that category.

Here is a list of 68 drugs that are known to work, but apparently we don't know how or why:

https://en.wikipedia.org/wiki/Category:Drugs_with_unknown_me...