There are in fact a lot of supplements that are effective. Magnesium for heart issues, Calcium for bone density, creatine for weight lifting.

There are also a lot of supplements that do nothing. The "snake oil".

Examine exists so that you can use studies to determine which is which.

Snake oil per se is an analogue of fish oil, effective. It's use as a pejorative term dates to false advertising of petroleum as actual snake oil in the 19th century. The biggest problem was it wasn't well processed at the time, and was not really edible like petroleum derivatives can now be made to be.

And I generally don't take it at face value, I accept it as a glitch in English.