Vitamin D for Fibromyalgia

Foods with vitamin D, including fatty fish, cereal, milk, and orange juice are displayed on a white background.

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Fibromyalgia (FM) researchers have long noted that the condition’s symptoms bear a striking similarity to the symptoms of vitamin D deficiency. For more than a decade, studies have suggested that people with fibromyalgia may be especially prone to vitamin D deficiency and that supplementation may be a worthwhile treatment.

However, this remains an active question, with research thus far being inconclusive. At the same time, you can find a lot of people online who say vitamin D does help ease their fibromyalgia symptoms.

Vitamin D’s Role in Your Body

Vitamin D plays several important roles in your body. It acts as a hormone, affecting:

  • Inflammation
  • Pain
  • The nervous system (brain and nerves)
  • The immune system
  • Bone strength
  • Muscle health
  • Calcium and phosphorous levels

It’s hypothesized that vitamin D acts as an anti-inflammatory, which can help it relieve musculoskeletal pain. It’s believed to lower inflammation by influencing T cells in your immune system so that they produce fewer pro-inflammatory cells.

Vitamin D Deficiency

Being deficient in vitamin D can lead to a number of health problems, many of them serious, including:

Vitamin D deficiency is also tied to symptoms such as:

  • Fatigue
  • Pain in the bones
  • Muscle weakness, aches, or cramps
  • Depression and other mood changes
  • Balance problems and frequent falls
  • Poor sleep

Vitamin D and FM Symptoms

Fibromyalgia involves dozens of possible symptoms. Some of the main symptoms include:

When you compare this list to those above, it’s easy to see why vitamin D deficiency is suspected in this condition. Whether its role is as a cause or contributor to FM’s development, a cause of symptoms, or an effective treatment remains to be determined.

Inflammation and autoimmunity in fibromyalgia are newer directions of research. Autoimmune disease, which is caused by an overactive and malfunctioning immune system, usually involves significant amounts of inflammation.

Typically, however, someone diagnosed with fibromyalgia has normal or only slightly elevated markers of inflammation in their blood, and there’s no visible swelling in painful areas. This has led many healthcare providers to conclude that fibromyalgia isn’t an autoimmune disease and doesn’t involve inflammation.

Newer research has cast doubt on that, though. Evidence is growing that suggests neuroinflammation (inflammation in the brain and nerves) as well as damage to certain nerve structures, including the optic nerve and what are called “small fiber” nerves.

Other research has suggested inflammation of the thin web of connective tissues called the fascia, as well.

Thus, it may well be that inflammation and autoimmunity play a key role in fibromyalgia, which would make vitamin D not only a suspect in the cause of the condition and its symptoms, but a potential treatment for it, as well.

Fibromyalgia Healthcare Provider Discussion Guide

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What Research Says

Research on vitamins and supplements typically isn’t as robust as studies of pharmaceutical drugs, and that definitely goes for research into vitamin D for fibromyalgia. However, a growing body of literature has been amassed over the past two decades.

A 2018 review of literature on vitamin D and fibromyalgia says the body of research “suggests a positive association between the diagnoses” of FM and vitamin D deficiency. At the same time, the authors note that the evidence is inconsistent.

Specifically, many of the studies were too small to say anything certain. The different studies have employed different methods, making them hard to compare to each other. Additionally, some of the studies didn’t fully account for other factors that could have affected the results.

For now, the researchers say we don’t have a clear picture of the risk versus benefit of using vitamin D supplements as an FM treatment, and they say healthcare providers should consider it on a case-by-case basis.

Some of the more convincing evidence they cited involved associations between low vitamin D levels and specific FM symptoms, including:

In various FM studies, low vitamin D has predicted more severe pain, higher tender-point counts, and poorer daily functionality. In one study, vitamin D supplements consistently relieved pain severity, with the impact maintained at follow up 24 weeks after participants stopped taking the supplements.

Importantly, reviewers said the highest-quality studies did indicate that people with FM had significantly lower vitamin D levels than healthy people in the control groups.

A 2017 meta-analysis had a similar finding, saying “vitamin D serum levels of patients with fibromyalgia was significantly lower than that of [the] control group.”

In a small study published in 2018, researchers identified people with both fibromyalgia and vitamin D deficiency and gave them extremely potent supplements of 50,000 IU of vitamin D once a week for three months. Vitamin D levels increased significantly over the three months, and pain levels and tender-point counts dropped.

A 2017 study in The Eurasian Journal of Medicine found evidence linking vitamin D deficiency to the development of FM and the authors suggested the healthcare providers check serum vitamin D levels in their FM patients.

A study that same year in The Journal of Endocrinology says that vitamin D supplementation can improve sleep, which in turn can alleviate hyperalgesia, a hallmark symptom of FM dealing with amplified pain signals.

In a 2018 study out of Iran, researchers found that combining vitamin D supplements with antidepressants significantly improved symptoms, both physical and mood-related, in vitamin-D deficient fibromyalgia participants.

A 2017 study in Modern Rheumatology showed a correlation between low vitamin D and balance issues in FM. On the other hand, a 2019 study found only a non-significant link between FM and low vitamin D.

Some studies have shown no correlation between FM symptoms and vitamin D, and no higher prevalence of vitamin D deficiency in participants with FM—including a 2020 study in the Journal of Clinical Medicine Research. That one did suggest, though, that people in the fibromyalgia group with the most severe disease did consistently have lower concentrations of vitamin D.

Getting More Vitamin D

If you’ve been diagnosed with a vitamin D deficiency or believe more vitamin D could improve your fibromyalgia symptoms, first, talk to your healthcare provider about the best way to increase your levels.

They may give you a high-dose supplement to rapidly bring them up, or they may recommend supplements or dietary changes. Supplements are an easy, consistent way to get enough vitamin D. However, it’s also pretty easy to increase your levels through diet and lifestyle.


Your skin creates vitamin D from ultraviolet B (UVB) rays, so if you don't get much sun exposure, increasing it could help raise or maintain your vitamin D levels.

About 15-20 minutes of sun exposure three times a week is considered sufficient for people with light skin. If you have darker skin, you need more sunlight to get the same benefit.


To get more vitamin D through your diet, you can include more of the following foods and beverages:

  • Egg yolks
  • Swiss cheese
  • Tuna
  • Salmon
  • Swordfish
  • Cod liver oil
  • Mackeral
  • Beef liver
  • Mushrooms

Some common foods that don’t naturally contain vitamin D are frequently fortified with it, including:

  • Milk
  • Yogurt
  • Orange juice
  • Cereal
  • Soy drinks

Recommended Daily Vitamin D Ranges

0-6 months: 400-1,000 IU

6-12 months: 400-1,500 IU

1-3 years old: 600-2,500 IU

4-8 years old: 600-3,000 IU

9-70 years old: 600-4,000 IU

70 and older: 800-4,000 IU

Symptoms of Too Much Vitamin D

It is possible to get too much vitamin D, which is known as vitamin D toxicity. Symptoms include:

  • Nausea
  • Vomiting
  • Poor appetite
  • Constipation
  • Weight loss
  • Weakness
  • Kidney damage

Because your body uses vitamin D to regulate calcium levels, too much vitamin D can lead to excess calcium in your blood, which is called hypercalcemia. It can cause:

  • Confusion
  • Disorientation
  • Heart-rhythm problems

Vitamin D toxicity usually results from using supplements, not dietary sources or sunlight exposure.

A Word From Verywell

While it’s too soon to say for sure whether vitamin D is a safe and effective treatment for fibromyalgia, some of the evidence is compelling. If you are taking more than 1000 IU of vitamin D a day, you should have your healthcare provider check your vitamin D levels with a simple blood test.

Because supplementation with vitamin D does carry some risks, be sure to discuss it with your practitioner before starting and carefully follow directions from your medical professional/pharmacist or on the product label.

16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Adrienne Dellwo
Adrienne Dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic.