Are there any side effects to taking a B12 supplement?
                                
                                
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                                    4 min read                                
                            
                                According to the National Institutes of Health, vitamin B12 has not been shown to cause harm, even at high oral doses, since the body excretes excess amounts. This brings peace of mind to many, but it still begs the question: are there any side effects to taking a B12 supplement?