How Long Does It Take to Have an Allergic Reaction to a Vitamin?
                                
                                
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                                    4 min read                                
                            
                                While severe anaphylactic reactions to vitamin supplements are rare, most allergic responses can happen within an hour of taking a vitamin, while others may be delayed by hours, days, or even weeks. The answer to **how long does it take to have an allergic reaction to a vitamin?** depends heavily on the type of reaction and the specific substance triggering the immune response.