The Recommended Dietary Allowance (RDA) for vitamin D is 600 International Units (IU ... vitamin D supplements are available ...

Vitamin D experts now believe we need at least 1000 IU’s a day to keep blood levels at a healthy level. Vitamin D3 (“cholecalciferol”) is better at keeping your blood levels up than vitamin D2 ...

1,000 IU (25 mcg) of vitamin D per day over several months should be taken to achieve a normal blood level or 40 ng/ml (100 nmol/L). Upon reaching the goal, most individuals need to supplement ...

Here's how: Related: What Is Vitamin D3? And How Is It Different ... Doctors reccomend taking 1,000 to 2,000 IU of a D-3 ...