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General Information

"In the treatment of a patient, where proven prophylactic, diagnostic and therapeutic methods do not exist or have been ineffective, the physician, with informed consent from the patient, must be free to use unproven or new prophylactic, diagnostic and therapeutic measures, if in the physician’s judgement it offers hope of saving life, reestablishing health or alleviating suffering."

Declaration of Helsinki


The following Q&A give an overall view of the Coimbra Protocol. For specific information please see the links at the bottom of the page and our list of doctors around the world:


What is Vitamin D?

Despite of its name, vitamin D is not a vitamin. It is a steroid hormone necessary by our body to regulate at least 229 of our genes and thousands of functions in our cells, including the cells of our immune system.  Vitamin D is found in small quantities in food and is primarily produced by the skin when exposed to sunlight. This sun exposure is affected by many factors, such as time of day, the use of sunscreens and geographic location. It has been correlated that areas further from the equator have increased incidence of autoimmune conditions, specifically multiple sclerosis.

What is a physiological dose of vitamin D?

A physiological, safe dose of vitamin D is about 10,000 IU/day. This is the amount our own body produces when exposed to 20-30 minutes to the mid-day sun. With this daily dose, no precautions or medical supervision is necessary. It is worth noting that the IOM (Institute of Medicine) indicates that 10,000 IU/day is considered the "NOAEL"- No Observed Adverse Effect Level.

Why do patients on the Coimbra Protocol need such high doses of vitamin D?

With adequate levels of vitamin D, essential cellular processes will unfold properly; however, the majority of patients with autoimmune diseases have an increased resistance to the effects of vitamin D. This resistance is mostly due to genetic polymorphisms, and may also be influenced by factors such as body weight, body mass index, and age. Consequently, patients with autoimmune disorders require higher levels of vitamin D to overcome this resistance and unlock the beneficial effects of this important substance at their cells and tissue.

Why is vitamin D effective for autoimmune diseases?

Vitamin D is the largest regulator of activity in the immune system. When there is a deficiency of vitamin D, the patient can't regulate, which means stimulate or reduce, the activity of thousands of biological functions inside the cells of the immune system.

Vitamin D suppresses autoimmunity by suppressing the Th17 reaction, which is caused by overproduction of an "immune messenger" (cytokine) called "interleukin 17". Production of interleukin 17 is a natural phenomenon and is beneficial in adequate, regulated amounts. However, overproduction of interleukin 17 is not a natural phenomenon. So, autoimmune disease is the result of a dysregulated immune system that produces an aberrant immunological Th17 reaction, and Vitamin D is the substance needed to modulate this process.

At the same time, vitamin D also induces the proliferation of regulatory immune cells called "T lymphocytes".

It's also important to mention that vitamin D does not suppress the immune system; quite the contrary, it empowers the immune system against viruses, bacteria and other microorganisms.



Is there any scientific evidence for vitamin D and autoimmunity?

The correction of vitamin D deficiency in autoimmune diseases is a therapeutic approach based on scientific evidence. Studies have shown that vitamin D, in addition to the known role in calcium homeostasis, has numerous actions in the body, with major interventions in the immune system.

There are thousands of scientific, peer-reviews studies that show the relationship between multiple sclerosis and vitamin D3 deficiency, as well as the benefits of vitamin D supplementation for patients with such conditions.


Let's take a look at a few examples:

In 2009, a study presented at the annual meeting of the American Academy of Neurology found that high doses of vitamin D dramatically cut the relapse rate in people with multiple sclerosis. Patients in the high-dose group were given escalating doses of vitamin D for six months, to a maximum of 40,000 IU daily. Then doses were gradually lowered over the next six months, averaging out to 14,000 IU daily for the year. The patients given high-dose vitamin D in the study had lower relapse rate, and their T cell activity dropped significantly, when compared to the group who took lower doses

Burton, Jodie. “Is Vitamin D a Ray of Hope for Patients With MS?” Neurology Reviews 7;17.7 (2009) 1-16.

In 2011, a study conducted by 209 patients of systemic lupus erythematosus with the Ohio State University Medical Center found that the majority of patients included in the study had vitamin D deficiency. The authors concluded that vitamin D levels were negatively correlated with lupus disease activity. In other words, the more vitamin D in the blood, the lower the lupus disease activity, and vice versa.
Rovin, Brad H.; Vitamin D Deficiency As Marker for Disease Activity and Organ Damage in Systemic Lupus Erythematosus: [abstract]. Arthritis Rheum 2011;63 Suppl 10 :2276.

In 2013, a study supervised by Dr, Coimbra assessed the effect of prolonged administration of high-dose vitamin D on the clinical course of vitiligo and psoriasis. In this study, nine patients with psoriasis and 16 patients with vitiligo received 35,000 IU daily for six months in association with a low-calcium diet and hydration (minimum 2.5 L daily). The clinical condition of patients significantly improved during the treatment, with no signs of toxicity observed.The results of the trial suggest that, at least for patients with autoimmune disorders like vitiligo and psoriasis, a daily dose of 35,000 IU of vitamin D is a safe and effective therapeutic approach for reducing disease activity.

Finamor, Danilo C; Coimbra.“A pilot study assessing the effect of prolonged administration of high daily doses of vitamin D on the clinical course of vitiligo and psoriasis.” Dermato-Endocrinology 5.1 (2013): 222–234.

In 2015, a study published in PLOS Medicine demonstrated a genetic correlation suggesting that lack of vitamin D may be a cause of multiple sclerosis. Using a technique called Mendelian randomization, the authors examined 14,498 people with multiple sclerosis and 24,091 healthy controls. The study concluded that a genetically lowered vitamin D level is strongly associated with increased susceptibility to multiple sclerosis. According to Dr. Benjamin Jacobs, “This study reveals important new evidence of a link between vitamin D deficiency and multiple sclerosis. The results show that if a baby is born with genes associated with vitamin D deficiency they are twice as likely as other babies to develop MS as an adult. This could be because vitamin D deficiency causes multiple sclerosis.”

Mokry, Lauren E.; Ross, Stephanie; Ahmad, Omar S.; Forgetta, Vincenzo; Smith, George D.; Leong, Aaron; Greenwood, Celia M. T.; Thanassoulis, George; Richards, J. Brent. “Vitamin D and Risk of Multiple Sclerosis: A Mendelian Randomization Study.” PLOS Journal, 25 Aug. 2015. DOI: 10.1371/journal.pmed.1001866.

In 2015, a study published by the MS Society Cambridge Centre for Myelin Repair, demonstrated the important role of vitamin D in myelin repair. Researchers identified that the vitamin D receptor protein pairs with an existing protein, called the RXR gamma receptor, already known to be involved in the repair of myelin. By adding vitamin D to brain stem cells where the proteins were present, they found the production rate of oligodendrocytes (myelin making cells) increased by 80 percent.

Kohlhaas, Susan. “Vitamin D could repair nerve damage in multiple sclerosis, ” University of Cambridge. 07 Dec. 2015.

Not only patients with Multiple Sclerosis benefit from vitamin D modulating therapy but so do most of the common autoimmune diseases such as Rheumatoid Arthritis, Lupus, Psoriasis, Chron's Disease, among others.

What is the ideal dose of vitamin D?

The adequate levels of vitamin D are individual. The test that measures the serum level of vitamin D is called 25(OH)D3. Nevertheless, vitamin D levels are not used for dose adjustments on the Coimbra Protocol. The test that can evaluate each patient's magnitude of resistance to vitamin D is the PTH – parathyroid hormone.

Parathyroid hormone, or parathormone, is a hormone released by the parathyroid glands. Vitamin D suppresses the PTH; consequently, as vitamin D levels go up, PTH levels go down. If PTH were completely suppressed, this would mean that vitamin D would be working at its maximum biological potential. Since PTH cannot be completely suppressed, for it also has its purposes in the body, PTH levels are kept at its lowest normal limit. When PTH levels are at a minimum, the best biological effect of vitamin D is reached for that individual, regardless of the reason why he has a resistance.


How is the Coimbra Protocol applied?

Although the protocol includes other supplements besides vitamin D, achieving the correct level of vitamin D for each patient accounts for 95% of the treatment success. Therefore, in the beginning of treatment, PTH levels are measured, and then measured regularly during the treatment. If PTH is not at its minimum normal limit, vitamin D daily doses are increased until the desired PTH level is achieved. During the treatment, PTH levels are expected to go down to their lowest normal limit and stay there. When this happens, the resistance to vitamin D is overcome and the patient starts benefiting from its powerful immonodulatory effects. It usually takes two years to adjust the doses of vitamin D. After this period, the treatment consists in maintenance of the proper levels of PTH and calcium.

What are the required lab tests?

Some of the tests required by the protocol include, but are not limited to:

  • PTH

  • 24H Calciuria

  • B12 vitamin

  • 25(OH)D3

  • Total and Ionized Calcium

  • Urea and Creatinine

  • Albumin

  • Ferritin

  • Serum Phosphate

  • 24H Phosphaturia

  • TSH and FT4

  • Bone Densitometry

Are there side effects to the Coimbra Protocol?

The possible side effects of taking high doses of vitamin D for extended periods of time are an excess of calcium - in the blood (hypercalcemia) or in the urine (hypercalciuria), and loss of bone mass. Excess calcium can be easily avoided with a diet free of dairy and calcium-enriched foods, and regular lab tests to ensure calcium levels are kept under control.

To avoid loss of bones mass, patients on the protocol are instructed to practice a daily routine of aerobic exercises, like a 30 minute fast walk, for example. Those who cannot practice aerobic exercises might need medication with time, such as bisphosphonates, to prevent osteoporosis.

What is the recommended diet for the Coimbra Protocol?

The diet restrictions are related exclusively to the amount of calcium the foods contain. Dairy and calcium enriched foods must be avoided, nuts should be consumed in moderation. Again, every patient is different, so the test results will ultimately determine if the diet is being correctly followed or if more restrictions are needed. Also, patients need to drink 2.5 L of liquids a day, to ensure that the kidneys will be able to eliminate excess calcium without difficulty.

What other supplements are part of the Coimbra Protocol?

Recommended supplements can vary from physician to physician. Some of the supplements prescribed include, but are not limited to:


  • Magnesium (Glycinate, Malate, Citrate, etc.)

  • Magnesium Chloride

  • Vitamin B2 - Riboflavin

  • Omega 3

  • Vitamin B12

  • Chromium Picolinate

  • Selenium

  • Choline

  • CoQ10

How to find a doctor that prescribes the Coimbra Protocol?

This is the updated list of the doctors that are currently prescribing the Coimbra Protocol. Please make sure to click on the arrow at the  top left of the map's page to read important information about the professionals on the list.



Learn more:

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