Adding the clinical framing, because it changes how the question reads. The useful move here is to separate what is established from what is widely repeated. Those two sets overlap less than the confident tone of most write-ups suggests, and the second set is where nearly all the disagreement on this board comes from.

PeptideSynthNJ said:

Say what you would expect to see if you were wrong, before you look.

Genuinely useful, thank you. I had the facts and not the framework. Taking it to my next appointment.

Clinical perspective, offered as context rather than as advice. The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either. Those three things can all be true at once, and most arguments here are two people holding different parts of that.

JenPlateau said:

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

Adding a me-too, because a thread of one person's experience is not much use. I had assumed I was the exception until I read this.

Moderator note: reminder that nothing in this thread is medical advice, and that clinical claims need a source. Carry on.