Is it better to take vitamin D3 4000 IU or 5000 IU? A Dosage Comparison
                                
                                
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                                    4 min read                                
                            
                                For most healthy adults, the tolerable upper intake level for vitamin D is 4,000 IU per day, according to the National Institutes of Health. The question of whether it is better to take vitamin D3 4000 IU or 5000 IU depends on your specific health status and guidance from a healthcare professional.