It starts breaken down almost immediately once you swallow it, however for true benefits, most multi vitamins need to be taken AT LEAST for a month.
Well it starts working as soon as its disolved but to feel the benefits of the vitamin I would give it about a week or so to build in ur system
Depends whether they are water or fat soluble, in any event if you take a complete multivitamin daily your levels stay pretty constant.
I would think as soon as it is broken down in your stomach... Then it would be absorbed.. so fairly quickly.
I've always thought that it takes about 30min
Less than 15 minutes