Is 400 mcg too much? Understanding the Context of Your Supplement
                                
                                
                                •
                                
                                
                        
                                    
                                    4 min read                                
                            
                                While 400 micrograms (mcg) of folic acid is the recommended daily intake for most adults, especially for women of childbearing age to prevent birth defects, this same quantity is the tolerable upper intake level (UL) for selenium and far exceeds safe limits for vitamin D. The safety and efficacy of a 400 mcg dose are entirely dependent on the specific substance being consumed.