What does IE mean on vitamins?
                                
                                
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                                    4 min read                                
                            
                                According to the National Institutes of Health, some vitamins, particularly fat-soluble ones like A, D, and E, are measured by their biological activity rather than their weight. So, what does IE mean on vitamins? It's simply the German abbreviation for International Unit (IU), a standardized measure of a substance's potency.