1000 IU (25 mcg) per day increases vitamin D blood levels 10 ng/ml (25 nmol/L). 2000 IU (50 mcg) per day increases vitamin D blood levels 20 ng/ml (50 nmol/L). If the vitamin D blood test was 30 ...

In the United States, current guidelines suggest that consuming 400–800 International Units (IU), or 10–20 micrograms (mcg), of vitamin D should meet the needs of 97%–98% of all healthy people.