i suppose it is possible your finger nails, bones, etc. and mineral balance was already great and thus you wouldn't notice much if anything by supplementing with more. otherwise all the people i have seen in person, all have the same story, stronger thicker finger nails with the very first bottle.
often all the bad finger nail chips off, etc. but when the new finger nail finally reaches the end and is ready to be cut, they are stronger and more flexible.
after over a year, i have zero white spots, thick flexable finger nails that don't chip easily and the finger nails to form very small ridges which strengthens them.
ideally, hopefully a dropper a day of the potassium/iodine minerals will help keep your great health.