B12 for Fibromyalgia and Chronic Fatigue Syndrome

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B vitamins are essential for energy production, protein metabolism, red blood cell formation, and central nervous system maintenance. B vitamins are water soluble, meaning that your body uses what it can and eliminates the rest through urine.

Raw meat (chicken breast, pork chop, and beef steak)
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B12 is a common supplement for increasing energy. It's available in several forms, including injections, tablets, and sublingual (under the tongue) forms.

A few (but limited) studies suggest that low B12 levels may be involved in fibromyalgia and chronic fatigue syndrome. If so, it's possible that they are, at least in part, responsible for the low energy levels typical of both conditions.

Research on B12 supplements for these illness has just begun, but what little we have is promising. A 2015 study of B12 injections showed a positive response, especially in those who were also taking daily folic acid supplements.

Many healthcare providers disagree with this and consider B12 injections archaic and unsupported by scientific evidence. Some healthcare providers and researchers, however, say anecdotal evidence supports B12 supplements for achieving and maintaining higher B12 levels in people with these conditions.

Dietary Sources

B12 is readily available in almost any animal-derived food, such as:

  • Beef liver & other organ meats
  • Shellfish
  • Meat & poultry
  • Eggs
  • Milk & other dairy products
  • Fortified breakfast cereals
  • Nutritional yeast

Some vegetarian and vegan products are fortified with B12 since a plant-based diet generally will not contain enough. If you're on a special diet, you may want to talk to your healthcare provider and/or a nutritionist about how to best get enough important vitamins and minerals.

Side Effects

It's important to note that side effects are possible and potentially dangerous even with natural substances like B vitamins.

You should get medical attention right away if you experience any of the following:

  • Severe allergic reactions
  • Calf pain, swelling or tenderness
  • Chest pain
  • Feel of swelling throughout the body
  • Fever, chills or a persistent sore throat
  • Irregular heartbeat
  • Muscle weakness or cramping
  • Shortness of breath
  • Unusual bruising or bleeding


You don't need a prescription for B12 supplements. They're available from most places that sell supplements.

Still, if you're considering B12 supplementation, talk to your healthcare provider about it. (Remember that many healthcare providers are skeptical about B12 injections and may favor different types of supplementation.) If your healthcare provider knows about all of your treatments, he/she can give you better guidance and make sure you're not doing anything that's unsafe.

Your pharmacist is also a great resource when it comes to negative interactions between different treatments, including supplements.

5 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.
  1. Academy of Nutrition and Dietetics. What are B vitamins?

  2. Regland B, Forsmark S, Halaouate L, et al. Response to vitamin B12 and folic acid in myalgic encephalomyelitis and fibromyalgia. PLoS ONE. 2015;10(4):e0124648. doi:10.1371/journal.pone.0124648

  3. National Health Services. Treatment chronic fatigue syndrome (CFS/ME).

  4. National Institutes of Health Office of Dietary Supplements. Vitamin B12.

  5. Blumenthal KG, Ziegler JB. Hypersensitivity reactions, dietary supplements, and the importance of the case report. J Allergy Clin Immunol Pract. 2016;4(1):177-8. doi:10.1016/j.jaip.2015.08.001

Additional Reading

By Adrienne Dellwo
Adrienne Dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic.