[DantesKite]

I think this is true, with the caveat that men don't have periods like women do, so taking iron supplements every day for say 5 years might cumulatively add up for them.

But otherwise normal/daily supplements for a few months probably won't be negative and indeed, might even be beneficial for certain subpopulations, like athletes.

[danachow]

The otherwise healthy man with no iron deficiency has no reason to take daily iron supplements for 5 years and therefore no need to monitor iron levels. If they are iron deficient there is some sort of blood loss or underabsorption going on and if and until that is corrected an oral iron supplement is unlikely to cause toxicity. If it is corrected, then iron replacement should only take a few months.