Vitamin D Supplementation in MS

What's the Right Vitamin D Dose?

Studio shot of various pills in bottles
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Scientific evidence suggests a strong link between vitamin D and multiple sclerosis (MS), especially in terms of being a risk factor for developing MS.

One of the most compelling clues in this connection is the geographic distribution of MS. MS is much more prevalent in the northern latitudes, where there is less intense sunlight and colder weather, meaning that people get much less exposure to the sun.

Our bodies produce vitamin D from exposure to the sun's ultraviolet B rays.

Studies have also shown that vitamin D may play a role in how a person's MS progresses. For instance, vitamin D has been found to reduce MS relapses. There is also solid evidence that vitamin D, especially when taken with calcium, can help prevent osteoporosis, which is common in people with MS.

Supplementing With Vitamin D in MS

Based on the link between vitamin D deficiency and MS, it's not surprising that many neurologists check vitamin D levels and/or recommend vitamin D supplementation for their patients. That being said, there is currently no standard guideline stating exactly what a "normal" vitamin D level is and how much a person should take based on that level. 

Typical Vitamin D Dosing Strategies

If your doctor does recommend vitamin D supplementation, he or she will likely calculate your dose based on your vitamin D level, where you live, and the time of year—you may need more vitamin D during the winter months when there is less sunlight.

While not a hard and fast rule, a typical vitamin D dose is between 1,000 IU and 2,000 IU of vitamin D daily. If your vitamin D level is very low to start, your doctor may prescribe a higher dose, like 50,000 IU vitamin D weekly for 6 to 8 weeks, and then a lower daily dose, like 2000 IU. Again, the dosing is highly variable at this time and is mostly tailored to the individual patient.

What Happens if You Take Too Much Vitamin D?

The main consequence of vitamin D toxicity is hypercalcemia, which means that there is too much calcium in your blood. The symptoms include:

  • Nausea and/or vomiting
  • Irritability and/or confusion
  • Constipation
  • Fatigue
  • Decreased appetite
  • Weakness
  • Kidney stones

The treatment for vitamin D toxicity is stopping vitamin D supplements.

Bottom Line

All in all, the topic of vitamin D dosing and supplementation in MS is unclear at this time. More scientific studies need to be done to clarify how doctors should monitor and treat vitamin D levels in MS. For you, this means that it's best to only take vitamin D under the care of your personal MS doctor.


Bowling AC. National MS Society. Vitamin D and MS: Implications for Clinical Practice

Hathcock, J.N., Shao, A., Vieth, R., & Heaney, R. (2007). Risk assessment for vitamin D. American Journal of Clinical Nutrition, Vol. 85, No. 1, 6-18.

Heaney, R.P. (2008). Vitamin D: criteria for safety and efficacy. Nutrition Reviews, Oct;66(10 Suppl 2):S178-81.

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