Folic Acid for Fibromyalgia & Chronic Fatigue Syndrome

What Can It Do for You?

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Folic Acid Basics:

You probably associate folic acid with pregnancy, since it's commonly recommended for preventing birth defects. Folic acid does a lot more than that, though, and it's even gotten attention as a potential treatment for fibromyalgia and chronic fatigue syndrome.

Folic acid is also called vitamin B9 or folate. It plays a role in:

  • Turning food into fuel,
  • Using fats and protein,
  • Keeping hair, skin, and eyes healthy,
  • Brain/nerve function,
  • Liver health,
  • Heart health,
  • Cancer prevention,
  • Production of genetic material,
  • Making iron and red blood cells work properly.

Some studies suggest that folic acid may help alleviate depression; however, results are mixed.

Folic acid and vitamin B12 work closely together in many of these functions, and therefore it's often recommended that they be taken together.

Low folic acid levels are somewhat common. A true deficiency, however, is rare. Deficiency can lead to:

  • Mental sluggishness,
  • Forgetfulness,
  • Irritability,
  • Anemia (low red blood cell count),
  • Nerve problems in the limbs,
  • Diarrhea,
  • Loss of appetite,
  • Poor growth.

Folic Acid for Fibromyalgia & Chronic Fatigue Syndrome:

We don't have a lot of research on folic acid for fibromyalgia and chronic fatigue syndrome. Studies done back in the 1980s and '90s produced mixed results, but more recent ones have suggested that it may play a positive role in our treatment.

A 2006 study (Lundell) provided evidence that more than 80% of people with chronic fatigue syndrome, especially those with B-cell immunodeficiency and reactivated Epstein-Barr virus infection, saw their symptoms improve on folic acid supplements.

A 2015 study (Regland) supported the use of folic acid and B12 supplementation in chronic fatigue syndrome, especially in those with comorbid fibromyalgia.

Researchers concluded that higher dosages led to better response, especially in those with both conditions. However, those regularly taking opiate painkillers, Cymbalta (duloxetine), or Lyrica (pregabalin) on a daily basis reported a lesser effect. That led researchers to suspect a negative interaction between the drugs and supplements.

It's common to see nutritionists and natural healers suggest folic acid as a treatment for fibromyalgia and chronic fatigue syndrome as well.

Folic Acid in Your Diet:

Folic acid is readily available in foods. Common dietary sources include:

  • Asparagus,
  • Avocado,
  • Beef liver,
  • Beets,
  • Brussel sprouts
  • Kidney, lima, white and mung beans,
  • Milk,
  • Orange juice,
  • Root vegetables,
  • Salmon,
  • Spinach and other dark leafy greens,
  • Wheat germ,
  • Whole grains.

In the US, all grain and cereal products are fortified with folic acid.

Folic Acid Dosage:

If you choose to take folic acid supplements, first check on whether you're already getting it in a multivitamin or B-vitamin complex.

In adults, the recommended daily allowance of folic acid is 400 mcg.

(Higher doses are suggested for pregnant and breast-feeding women.)

It's often recommended that you take a B-complex supplement because long-term supplementation with one of the B vitamins may lead to imbalances in the others. Also, folic acid supplements may mask symptoms of a dangerous B12 deficiency.

Side Effects of Folic Acid:

Any supplement you take has the potential to cause unwanted side effects. Side effects from folic acid are rare at the recommended daily allowance. High doses may lead to:

  • Confusion,
  • Loss of appetite,
  • Nausea,
  • Seizures,
  • Skin reactions,
  • Sleep problems,
  • Stomach problems.

The following medications may interact negatively with folic acid:

  • Antibiotics,
  • Dilantin (phenytoin),
  • Daraprim (pyrimethamine),
  • Chemotherapy medications.

Many drugs can interfere with folic acid levels or absorption rates, including some that are common for those of us with fibromyalgia and chronic fatigue syndrome. Those include:

  • Anti-inflammatories (NSAIDs) such as Aleve (naproxen) or Advil/Motrin (ibuprofen);
  • Azulfidine (sulfasalazine) for rheumatoid arthritis or inflammatory bowel disease;
  • Acid blockers, including antacids, H2 blockers (cimetidine, famotidine, ranitidine), and proton pump inhibitors (lansoprazole, omeprazole, rabeprazole).

Your doctor can help you identify any potential interactions and the pinpoint the correct dosage for you. It's also never a bad idea to check with your pharmacist about interactions—they may be aware of some that your doctor is not.

More Supplement Information:

To learn more about taking supplements for fibomyalgia and chronic fatigue syndrome, see:


Harmon DL, et al. annals of clinical biochemistry. 1997 Jul;34 ( Pt 4):427-9. A common genetic variant affecting folate metabolism is not over-represented in chronic fatigue syndrome.

Jacobson W, et al. Neurobiology. 1993 Dec;43(12):2645-7. Serum folate and chronic fatigue syndrome.

Kaslow JE, Rucker L, Onishi R. Archives of internal medicine. 1989 Nov;149(11):2501-3. Liver extract-folic acid-cyanocobalamin vs placebo for chronic fatigue syndrome.

Lundell K, et al. Arzneimittel-Forschung. 2006;56(6):399-404. Clinical activity of full and a gas it in patients with chronic fatigue syndrome.

Regland B, et al. PLoS One. 2015 Apr 22;10(4):e0124648. Response to vitamin B12 and folic acid in myalgic encephalomyelitis in fibromyalgia.

University of Maryland Medical Center. All rights reserved. Vitamin B9 (Folic acid). Accessed July 2015.

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