Question: how many iu is 2 mcg of vitamin d?
Answer: 100 IU (2.5 mcg) per day increases vitamin D blood levels 1 ng/ml (2.5 nmol/L). 200 IU (5 mcg) per day increases vitamin D blood levels 2 ng/ml (5 nmol/L). 400 IU (10 mcg) per day increases vitamin D blood levels 4 ng/ml (10 nmol/L). 500 IU (12.5 mcg) per day increases vitamin D blood levels 5 ng/ml (12.5 nmol/L).