A narrower follow-up, since the general answer is now clear:

How long did you give it before you decided it was working?

TirzTom said:

The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either.

This is where I part company with the consensus forming above. Not convinced. The evidence being cited is consistent with the conclusion and also consistent with two other conclusions nobody has ruled out.

TirzTom said:

The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either.

True, with the qualification that this is a self-selected group. The people for whom it did not work post less, and that shapes everything we think we know.

TirzTom said:

The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either.

This answered a question I did not know how to ask. Adding it to my notes with a link back to this thread.

Clinical perspective, offered as context rather than as advice. Worth answering the question that was asked rather than the one behind it. The narrow version usually has an answer; the broad version usually does not, and answering the broad one is how a thread stops being useful.

Correct me if the detail matters more than I have assumed.