What about when it does work for people as an oral decongestant though? Are you suggesting that's just randomness? Or perhaps the placebo effect? I guess I'm not entirely convinced it's really useless for that purpose, but I'm just a layman.
Here's my theory: you know that pseudoephedrine works, so taking this thing that's supposed to be a replacement for it, and sounds pretty similar, will convince your brain that phenylephrine will also work. So yes, placebo, but with foreknowledge of the effectiveness of pseudoephedrine. I'm curious if there have been placebo-controlled studies on phenylephrine where the participants were told they were receiving pseudoephedrine
