Dr.PeteFamMed said:

The glucagon component looks paradoxical and is not.

Bookmarking. The distinction being drawn above is the one nobody else makes.

Adding the clinical framing, because it changes how the question reads. 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.

Worth separating that from thyroid monitoring, which this thread keeps folding into the same question. They behave differently and the advice does not transfer.

NurseLeah_Nash said:

Routine calcitonin screening is not recommended and does more harm than good in this population — the false-positive rate is high and the workup is…

Filing a mild objection. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit. Pushing back on the anecdote-stacking. Twenty people reporting the same thing is twenty samples from the same self-selected pool, not twenty independent confirmations.

The figures, for anyone assembling their own picture. For anyone reading later: the numbers in this thread are worth checking against a primary source before you act on them, including mine. Half the figures circulating in this community trace back to a secondary summary that dropped a qualifier.

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

Moderator note: good thread. Keeping it here rather than moving it, because the question is general enough to be useful. No action needed from anybody.