That's what right to try is. There are people who believe that should not be the case.
But the same logic also works for anything non-fatal as long as the proposed treatment is also non-fatal. If you want to try something and it probably won't work but it also probably won't cause permanent damage, there is nobody who should stop you from finding out what happens for yourself.
And in general nobody will stop you doing stuff to yourself.
The problem comes when these things are advertised or otherwise promoted. Ideas don't exist in a vacuum, they can become cultural parasites for all sorts of reasons, and even if they don't begin as a scam, there are always a bunch of get-rich-quickers waiting in the wings to sell, say, sheep dewormer to people with a respiratory virus.
> And in general nobody will stop you doing stuff to yourself.
The relevant doing stuff to yourself here is that you want to take some particular drug. Unless you're a competent chemist with the relevant equipment, that implies that somebody would have to be able to sell it to you in order for you be able to do it.
Also, what happens if the thing you want to do to yourself is to take MDMA?
But the same logic also works for anything non-fatal as long as the proposed treatment is also non-fatal. If you want to try something and it probably won't work but it also probably won't cause permanent damage, there is nobody who should stop you from finding out what happens for yourself.