Why isn’t my Vitamin D working?


Q. When I saw my doctor for my annual physical, he did a blood test for vitamin D and it came back deficient. Although live in Southern California, I tend to avoid the sun and keep covered when I am out in it. But my daily multivitamin contains 1,000 IU of vitamin D.  My doctor recommended adding another 1,000 IU to that. My question is, why didn’t the vitamin D in my multivitamin work? 

A. When you are deficient in vitamin D, it can take a surprisingly high dose of oral vitamin D to correct it. (Exposure to sunlight is much more efficient .) My guess is that the 1,000 IU in your multivitamin simply wasn’t enough to dig you out of the hole you’d dug yourself into, thanks to your diligent avoidance of UV rays.

But 2,000 IU may not be enough either. Effective protocols for treating vitamin D deficiency often involve taking 10,000 IU per day for 2-3 months. Fortunately, high doses of vitamin D are quite safe.

Hopefully, your doctor will order another blood test to check your vitamin D levels again before too long. If they haven’t moved (which is fairly likely), he may suggest a higher dose or even give you an injection.

Once you get your vitamin D levels up where they should be, 1,000 to 2000 IU per day should be more than enough to keep you there.


6 thoughts on “Why isn’t my Vitamin D working?

  1. Hi Monica, I was diagnosed with vitamin D deficiency a few months ago. My level was 23. I was told to take a 2000 Iu. supplement daily. After a couple days I broke out in a rash. I was told it may be the oil in the gel tabs. So, I switched to a dry tablet. To be on the safe side, I broke it in half to see if it would still cause the rash. It did. Any suggestions?

    1. Apparently, this is an uncommon but not unheard of reaction. I’m not sure what to suggest. Does your doc have any ideas?

  2. The only suggestion was to keep trying different brands. I’m not sure that is a cost effective solution. I guess I’ll just try to get more D from natural sources. I don’t think I’ll be able to get enough that way, but I guess it’s better than nothing.

    1. Vitamin D can also be administered by injection but if the reaction is to the vitamin itself (as opposed to a binder or other ingredient), I’m not sure that helps. The fact that your doctor suggested trying different brands suggests that she thinks the reaction is not to the vitamin itself. There are also sun lamps that can promote vitamin D formation in the skin, but these obviously need to be used cautiously to avoid skin damage.

  3. Thanks Monica. I want you to know how much I enjoy reading your newsletter. I have learned a lot from you. I have gluten intolerance and Hashimoto’s disease. I’ve read that both can impact Vitamin D levels. Thanks for your input.

  4. I am 13 years old and I have been in my everyday all day and then all of the sudden I feel like I am going to pass out I went to my mom and I went to the doctor they took blood and told me my vitamin d was a 5 and that it should be on 30 I got my medicine and it worked for a while but then I missed a certain time to take my medicine not I feel the same but I have this week to take my medicine.

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