What Do You Mean 
”Too Much Vitamin D?”

A senior woman holding a bottle of pills

In the first three blogs of this series I discussed the relationship among magnesium, calcium, Vitamin D, and Vitamin K; the magnesium factor; and the calcium myth. Today I am going to share one of my most controversial views – you can supplement too much and/or the wrong kind of Vitamin D.

Too Much Vitamin D?

You get your annual checkup including blood tests. Your doctor tells you that your Vitamin D is too low. He/She gives you a prescription for high dose Vitamin D (50,000 IU or more). You start using the supplements and experience eye twitches and muscle spasms. What’s wrong with this picture? Why didn’t taking high dose Vitamin D improve how you feel?

As a doctor and practitioner of over 50 years of experience, I’m not sold on high-dose, synthetic Vitamin D supplementation. Here are my reasons:

  • My first questions about the safety of high dose Vitamin D came when I heard about people taking high doses and developing magnesium deficiency symptoms, including seizures. 
  • When we measure Vitamin D, we are measuring the storage form and not even the active form. So, how do we really know what’s going on?
  • The body can’t possibly process incredibly high doses like 50,000 IU of synthetic Vitamin D a day.
  • Synthetic Vitamin D is made from lanolin from sheep’s wool. Once people know this, they hardly want to take this form of Vitamin D.
  • Vitamin D is not even a vitamin but it’s really a hormone that requires magnesium to turn it into the active form.
  • Since Vitamin D is a hormone with a feedback loop for calcium, when D levels are low, does that mean it has enough calcium and doesn’t want to make more Vitamin D to pull in more calcium?
  • We are a calcified country, so the effect of high calcium may be lower levels of Vitamin D. And without understanding the complex chemistry involved, most people think we just need to take more.
  • When you take that much Vitamin D, the strain on magnesium is dramatic. The accumulation of calcium is dramatic. And there are probably many other consequences that we don’t even know about.
  • A very intensive randomized, double-blind, placebo-controlled study concluded that: “Calcium and Vitamin D supplementation may cause hypercalciuria (excess calcium in the urine) and hypercalcemia (a condition in which the calcium level in your blood is above normal) in some postmenopausal women.”
  • Kidney stones have been reported in previous research in women who take calcium and vitamin D supplements compared with placebo.

My Vitamin D Recommendation

My recommendation for Vitamin D supplementation is contained in my Supplement Recommendations– No. 9. As you can see, you can spend 30 minutes in the sunlight (You will still need magnesium to convert this Vitamin D to a usable form.) or 1,000-2,000 IU of natural Vitamin D daily. In my next post, I will talk about the product I use as well as give you a starting point for your research on Vitamin K.

Start Your Own Exploration

In order to get the most benefit from supplementing Vitamin D, please make sure to supplement magnesium so that you don’t experience or increase your magnesium deficiency. To start exploring the importance of this combination, please begin your research with Magnesium and Vitamin D – It Takes Two to Tango!


Dr. Carolyn Dean

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