How long it takes for vitamins and supplements to work depends on factors like the type of vitamin, your diet and hydration, ...

Dear M.E.B.: I think many media sources avoid the complexity of the issue. The preferred unit to describe doses of vitamin A are now micrograms RAE, or “retinol activity units.” Different vitamin A ...

Women who might become pregnant should be especially cautious with vitamin A supplements or avoid them entirely .

For example, 3,000 IU of vitamin A (as retinol) is 900 mcg RAE. About 18,000 IU beta carotene, which is less potent than ...

If I am taking vitamin A, what is a reasonable dose? I have seen reports that taking too much can cause liver damage, but ...