Even funnier is that often 0.25mg or 0.5mg is closer to the correct dose, and those sizes tend to be hard to find.

There actually is a condition that calls for extremely high (100mg+ doses), but it is a very rare thing, no one should ever consider that much without instruction from a doctor. But you'll find it right next to the normal <=5mg doses without any explanation.

The Natrol liquid isn't usually too hard to track down. They advertise it as 1 mg or 2.5 mg, but it's the same stuff, the bottle just direct you to take 4 or 10 mL respectively.