From the other side of the consultation, briefly. 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.

If somebody has the primary source to hand I would rather cite it than paraphrase it.

pete_nash 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.

pete_nash said:

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

There is a second half to this that has not been said yet. Whatever the answer turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, and invite the correction. That is slower than asserting, and it is the only version that survives being wrong.

One concrete data point for the thread. Worth stating the units and the reference range whenever you post a number here. A large fraction of the apparent disagreement in these threads is two people using different units and both being right.

One thing that is still open after pete_nash’s answer:

What would you measure differently if you were starting again?