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 ...

There are two types of vitamin D supplements available for over-the-counter purchase (vitamin D2 and vitamin D3). Vitamin D3 is the type that most experts believe should be utilized in clinical ...