vit d3

• Vitamin A: 1 IU is the biological equivalent of 0.3 mcg retinol, or of 0.6 mcg beta-carotene
• Vitamin C: 1 IU is 50 mcg L-ascorbic acid
• Vitamin D: 1 IU is the biological equivalent of 0.025 mcg cholecalciferol or ergocalciferol
• Vitamin E: 1 IU is the biological equivalent of about 0.67 mg d-alpha-tocopherol, or 0.9 mg of dl-alpha-tocopherol.

Example conversion

Let's say that I have a soft gel capsule that contains 500 IU of Vitamin A as retinol. To convert this to mcg, using the information above, I would multiply it by 0.3:
500 × 0.3 = 150mcg.
Conversely, if the soft gel capsule was described as '150mcg of Vitamin A as retinol' and I wanted to convert to IU, I would divide it by 0.3.
150 ÷ 0.3 = 500 IU.
Note that the information contained here is purely for casual interests and is not intended to replace your doctor's advice. Please use it at your own risk. As with all calculations where health could suffer from inaccurate conversions, you are advised to check with a health professional before taking a dosage of any vitamin or supplement.