Unfortunately, this is quite common among parents who want to make their own infant formula. They don't know how to dose milligrams and give ten or a hundred times the prescribed dose to infants.
Actually, it is possible to overdose on vitamin D, though it’s relatively rare. Vitamin D toxicity, also known as hypervitaminosis D, occurs when there is an excessive amount of vitamin D in the body. This can happen through very high doses of supplements over an extended period or by accidental ingestion of high-dose vitamin D supplements.
everything including water can be toxic at high doses. when I say its not really a thing, it means that it is indeed very uncommon compared to the amount of people who take supplements.
Ok, so paracetamol (aka Tylenol, acetaminophen) overdose is also 'not really a thing', because despite it being absolutely possible to trash your liver and die, the number of people who do that (including as a suicide attempt, as does happen) is miniscule compared to the approximately everybody who takes it.
The safety margin for Vitamin D is on a totally different scale vs the safety margin of Paracetamol (which is very thin, it's easy to overdose on it). bad analogies are bad.
