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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

My doctor said that my Vitamin D level is low at 25. He prescribed Vitamin D3 50,000 IU three times a week. I read about adverse effects of taking such a high dose, so instead I've been taking 4000 IU daily. My sister and my daughter both have lower levels than I do and are only taking 2000 IU daily. I'm due for another blood test only 3 weeks after started taking the 4000 IU. Is this too soon to have another blood test? What are your thoughts of taking 50,000 IU three times a week?

Ask the Vitamin D Council

Asked by  peggys846321700 on September 29, 2016


  • peggys846321700
     peggys846321700 on

    See title

    Answered by  peggys846321700 on

  • IAW
     IAW on

    If your level was measured as ng/ml and not nmol/l, this is what I think. (If measured as nmol/l, I would give you a different story.)
    Your level of 25ng/ml is low but really 50,000iu 3 times a week seems excessive UNLESS you are having major medical issues. Most doctors would prescribe 50,000iu ONCE a week and that equals about 7-8000iu a day. After about 8 weeks of treatment then levels should be checked to make sure they have increased. We here at the VDC recommend maintaining a “healthy” level of 50ng/ml. At levels below 40ng/ml, your chances for cancer and autoimmune diseases “rise dramatically.” (Also keep in mind D3 is much better to take than prescription D2.It is also better to take D daily rather than weekly.)
    Now at your level, if you take 5000 iu a day, you should reach the 50ng/ml in 8 weeks. The 5000iu is based on an average weight of 150lbs. If you weigh more, you have to take more.
    It takes about 8 weeks, taking the same amount of Vitamin D, to reach a level you can base that amount on. For example if you take the 4000iu for 8 weeks and then test again, you should make it close to the 50ng/ml. If we pretend for a moment that you only test at 35ng/ml, then you will have to take more Vitamin D and retest in 8 weeks.
    Now it’s nice that your doctor wants to retest in 3 weeks but the most they should look for is are your levels increasing because it will take 8 weeks to get the full affect.
    If your daughter is an adult, then her and your sister are not taking enough. It takes 5000iu a day to reach the healthy level.

    Answered by  IAW on