[legacynl]

All the quotes you posted basically say the same thing; There is no evidence for the efficacy of xenon. That's scientist speak for: "Xenon doesn't work".

[rtkwe]

Depends, it can also mean "this hasn't really been studied well" if there just hasn't been much research into it. I just pulled all the times it talked about studies or another expert talking about it being ineffective.

[mannyv]

It depends. It might mean that there are no studies that show efficacy or the lack thereof.

A lack of evidence doesn't mean it doesn't work. It depends on what you mean by 'evidence.'

Take one or two reports.

A scientist would say, 'that's an anecdote.'

A lawyer would day, 'I can send you to jail with those two reports.'