Vitamin D Supplementation in MS

What's the Right Vitamin D Dose?

vitamin d pills

Scientific evidence suggests a strong link between vitamin D deficiency and multiple sclerosis (MS). In fact, research suggests that vitamin D deficiency may be a risk factor for developing MS,

One of the most compelling clues in this connection is the geographic distribution of MS. Multiple sclerosis is much more prevalent in northern latitudes, where there is less intense sunlight and colder weather.

Since our bodies produce vitamin D from exposure to the sun's ultraviolet rays, little sun exposure can lead to a deficiency in vitamin D.

In addition, studies have 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, a disease of bone weakening that is common in people with MS. Therefore, preventing osteoporosis and subsequent bone breaks is another potential benefit of vitamin D supplementation in 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.

That being said, the Institute of Medicine reported that a vitamin D (25OHD) that is 50nmol/L or greater is "sufficient." Neurologists who treat MS though may want vitamin D levels that are even higher, like closer to 75 to 125nmol/L.

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. Some doctors may even recommend a maximum daily dose of 4000 IU daily. If your vitamin D level is very low to start, your doctor may also 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 signs and symptoms of hypercalcemia 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 and potentially other medical interventions to bring down the calcium levels in your blood.

A Word From Verywell

All in all, the topic of vitamin D dosing and supplementation in MS is still not totally clear at this time. More scientific studies need to be done to clarify how and when 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.


Alharbi FM. Update in vitamin D and multiple sclerosis. Neurosciences (Riyadh). 2015 Oct;20(4):329-35.

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

Hathcock JN, Shao A, Vieth R, Heaney R. Risk assessment for vitamin D. Am J Clin Nutr. 2007 Jan;85(1):6-18.

Heaney, RP. Vitamin D: criteria for safety and efficacy. Nutr Rev. 2008 Oct;66(10 Suppl 2):S178-81.

Simon KC, Munger KL, Ascherio A. Vitamin D and multiple sclerosis: epidemiology, immunology, and genetics. Curr Opin Neurol. 2012 Jun;25(3):246-51.