Fatigue & Fibro Fog: Could You Have a B-12 Deficiency?


A feeling of being tired all the time. Problems with memory and concentration. Trouble sleeping. Diarrhea and/or constipation. These can all be important signs of the body’s need for more vitamin B-12. 

Vitamin B-12 (cobalamin) is an essential nutrient, meaning it is required for normal body functioning but cannot be produced by the body.

Therefore, it is necessary to obtain the B-12 our bodies need through the food we eat and/or dietary supplements. 

A vitamin B-12 deficiency is relatively common – thought to affect approximately 15% of the general population. That percentage goes much higher among people with chronic illness. 

Because so many people are deficient in B-12 – particularly people with fibromyalgia and ME/CFS – and because a number of FM and ME/CFS specialists recommend high doses of B-12 for their patients, ProHealth’s founder, Rich Carson, set out to develop the most potent B-12 supplement available.

The result was B-12 Extreme™ – containing the world’s most potent single dose of all four forms of vitamin B-12 on the market. 

Symptoms of a Vitamin B-12 Deficiency

The symptoms of a vitamin B-12 deficiency are remarkably similar to many of the symptoms of fibromyalgia, ME/CFS, Lyme disease, multiple chemical sensitivities and Gulf War syndrome. While a B-12 deficiency is not thought to be the cause of these illnesses, it has been implicated as a possible factor in a number of different chronic illnesses.(1) The symptoms of a vitamin B-12 deficiency may include:

• Fatigue, weakness

• Memory loss

• Depression

• Confusion

• Insomnia

• Shortness of breath

• Poor sense of balance

• Vision problems

• Diarrhea or constipation

• Loss of appetite

• Cognitive functioning problems

• Beefy, red, smooth and sore tongue

• Sore mouth and/or bleeding gums

• Numbness and tingling of hands and feet

• Loss of hearing and tinnitus

• Pale, possibly yellowish pallor in light-skinned individuals; blotchy pigmentation in dark-skinned

The B-12 & Fibromyalgia-ME/CFS Connection

Since a B-12 deficiency has so many symptoms in common with FM and ME/CFS, researchers were naturally interested in whether or not low levels of B-12 could play a part in those illnesses. 

A 1997 study of 12 patients with fibromyalgia and ME/CFS found that most had little or no detectable B-12 in their cerebrospinal fluid – despite the fact that their B-12 blood tests were all normal. Conversely, they had high levels of homocysteine in their cerebrospinal fluid.(2)

Note: Homocysteine is an amino acid, too much of which can be toxic to nerves and blood vessels, and may result in increased pain sensitivity and/or heart disease. When there is not enough vitamin B-12, homocysteine levels increase. As B-12 levels rise, homocysteine levels decrease.

Well-known and highly respected specialists like Drs. Mark Pellegrino, Paul Cheney, Charles Lapp, Kenny DeMeirleir, Jacob Teitelbaum, and Martin Pall all recommend vitamin B-12 for their FM and ME/CFS patients. 

Dietary Sources of Vitamin B-12

Vitamin B-12 is produced exclusively in the digestive tracts of animals. The richest dietary sources of B-12 are beef liver and clams. Other good natural sources include meat, fish, eggs and dairy products. Some breakfast cereals are fortified with B-12; however, they do not contain adequate amounts to be used as the sole dietary source.

Are You Getting Enough B-12?

A better question might be “Are you absorbing enough B-12?

A deficiency of vitamin B12 is not usually caused by insufficient dietary intake but rather by a lack of intrinsic factor secretion. In order for the B-12 obtained from food to be absorbed by the body, it must attach itself to a protein called intrinsic factor, which is secreted in the stomach. Without intrinsic factor, vitamin B-12 cannot be absorbed.

Unfortunately, a number of things can inhibit the secretion of intrinsic factor, which in turn blocks the absorption of B-12 and results in a vitamin B-12 deficiency. High-risk factors for poor absorption include:

Digestive disorders such as celiac disease, Crohn’s disease, irritable bowel syndrome, bacterial overgrowth in the small intestine or a parasite.

Gastric bypass surgery.

Acid-reducing medications – Medications commonly prescribed for heartburn, GERD, acid reflux and peptic ulcers, such as proton pump inhibitors like Prilosec, Prevacid and Nexium, or H2 (histamine2) receptor antagonists like Pepcid and Zantac, suppress the secretion of stomach acids, also blocking the secretion of intrinsic factor. 

Diabetes medications – Drugs like Metformin, used to treat diabetes, are known to impair intestinal absorption.

Aging – The older we get the more likely we are to be deficient in B-12.(3) The Institute of Medicine (IOM) recommends that adults over 50 supplement their diets with vitamin B-12.(4)

Vegetarian and vegan diets – Since B-12 is only found naturally in animal foods, it is important for people on these diets to supplement their diets with B-12.

Pernicious anemia – a blood disease that develops when the body lacks the intrinsic factor necessary to naturally absorb vitamin B12 from food.

Diagnosing a Vitamin B-12 Deficiency

A B-12 deficiency can be difficult to diagnose because serum blood levels of B-12 may test normal. Having circulating B-12 in the blood doesn’t mean it is being utilized properly by the body’s cells.

Some doctors suggest that a test measuring methyl-malonyl coenzyme A levels in the urine gives a more accurate reading of B-12’s availability in the body.

However, because there are no known toxic effects, even at extremely high dosages, often doctors will prescribe vitamin B-12 based on symptoms and risk factors, rather than testing for a deficiency.

The Four Forms of B-12 – Which Is Best?

We tend to talk about vitamin B-12 as a single entity, but there are actually four different forms of B-12 in the cobalamin family – each with its own distinct purpose.

Promotes improved memory, focus and concentration. Is important for the central nervous system, playing a vital role in cell growth and nerve cell regeneration. Supports healthy homocysteine levels. Helps regulate circadian rhythms, which contributes to improved sleep quality and refreshment.(5) 

Adensylcobalamin (Dibencozide)
Promotes metabolism of essential fatty acids to produce more energy. Reacts with cells to provide muscles and nerves with bursts of energy.

The most common form of B-12 found in oral supplements and injections. Becomes active in the liver, creating enzymes to help with blood formation, cell reproduction, iron utilization, and tissue synthesis. Promotes the digestion and absorption of foods.

Helps remove heavy metals from the system and supports overall detoxification. Is FDA-approved as an antidote for cyanide poisoning. Important for smokers because it removes the cyanide found in cigarette smoke. Also assists with methylation (gene regulation) and energy production.

How do you know which form(s) of B-12 you need? You don’t have to decide. By combining all four forms of the vitamin, B-12 Extreme provides you with the best of each.

Injections or Pills – Is There a Difference?

Vitamin B-12 can be administered either orally or by injection. Since no one wants to get a shot unless they absolutely have to, it’s important to determine whether oral tablets are as effective as injections.

Two studies addressing that very issue concluded that oral supplementation with large doses of B-12 was as effective, if not more effective, than injections:

• A 1997 study showed that oral supplementation with 2,000 mcg per day was three times as effective as injections in increasing B-12 levels in pernicious anemia patients.(6)

• A review of two clinical trials, published in 2006, concluded that 2,000 mcg doses of oral B-12 were as effective as intramuscular administration in vitamin B-12 deficient patients.(7)

When it comes to oral supplementation of B-12, sublingual tablets are the best option because they are absorbed directly into the mucous membrane, by-passing the digestion process, which is often the cause of the deficiency to begin with.

Need-to-Know Information:

Safety:  The IOM has not established any maximum dosage for vitamin B-12 because “no adverse effects have been associated with excess vitamin B-12 intake from food and supplements in healthy individuals.”(4) Surplus B-12 is simply eliminated in the urine.

Dosage The suggested dose of B-12 Extreme is one tablet once or twice a day, or as otherwise recommended by your healthcare professional.

How to Take B-12 Extreme™ is a sublingual tablet. Place the tablet under your tongue and allow it to fully dissolve there. You should be aware that cobalamin, which is in all four forms of B-12, is an intense red color. As the tablet is dissolving, you may notice that your teeth, gums and sometimes even your lips appear to be red. Once the tablet has dissolved, the redness will begin to disappear on its own or you may want to brush your teeth to speed the process – particularly if you are going out.



1.  Fletcher RH, et al. “Vitamins for chronic disease prevention in adults.” JAMA. 2002;287(23):3127-3129.

2.  Regland B, et al. “Increased concentrations of homocysteine in the cerebrospinal fluid in patients with fibromyalgia and chronic fatigue syndrome.” Scand J Rheumatol. 1997;26(4):301-7.

3.  Stott DJ, et al. “Prevalence and haemopoietic effects of low serum vitamin B12 levels in geriatric medical patients.” Br J Nutr. 1997 Jul;78(1):57-63.

4. Institute of Medicine. Food and Nutrition Board. “Dietary Reference Intakes: Thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline.”  National Academy Press. Washington, DC, 1998.

5. Mayer G.,Kroger M., Meier-Ewert K. Effects of vitamin B12 on performance and circadian rhythm in normal subjects. Neuropsychopharmacology. 1996. vol. 15, no5, pp. 456-464.

6. Journal of the American Geriatrics Society. January, 1997; 45(1):124.

7. Butler CC, et al. “Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency: a systematic review of randomized controlled trials.” Fam Pract. 2006 Jun;23(3):279-85. Epub 2006 Apr 3.

Note: This information has not been reviewed by the FDA. It is general information, not intended to diagnose, prevent, treat or cure any illness, condition or disease, and should not replace the personal attention of a qualified healthcare professional. It is very important that you make no change in your healthcare plan or health support regimen without researching and discussing it in collaboration with your professional healthcare team.

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