From a few days ago.

"Probiotics labelled 'quite useless'"

https://news.ycombinator.com/item?id=17927802

I wonder how much of "X helped me" is a result of the placebo effect and how much of it is truly helpful.

The science is still out and likely will be for a long time, but I think people are generally too eager to label anything they don't understand as impossible or a placebo effect. Not everything true is scientifically known, or ever will be.