Reply To: Hello, My daughter has level 15.8 of Vit D. She is 19. Her naturopath wants her to take 10,000 units for the next month or two and then recheck. Her nutritionist says not to take this all at one time. The naturopath prescribed 10,00 unit capsules. Is this a problem for absorption? She is also iron deficient. She is also overweight and trying to get healthy. Please let us know if it is ok to take the 10,000 once a day. THANK YOU!!