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International Units (IU) are a measurement system for the activity of vitamins A, D and E. Many products, particularly in the higher dosage range, are still sold in International Units (IU).
Scientists no longer tend to use International Units, and prefer to measure vitamins by weight.
1 IU vitamin A = 0.3 mcg (micrograms)
1 IU vitamin D = 0.025 mcg
1 IU vitamin E = 0.7 mcg as d-alpha tocopherol
Other vitamins and minerals are measured by weight.
Milligram mg (equal to 1,000mcg)
Gram g (equal to 1,000mg)
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