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Vitamin B12 part of the Vitamin B complex is considered to be a “Painkilling vitamin”. It helps DNA production, cardiovascular support, and Energy metabolism.

Introduction to Vitamin B12


Vitamin B12 also referred to as cobalamin, is a water-soluble vitamin (R).

It contributes to the successful synthesis of DNA, the normal functioning of the nervous system, and the production of hemoglobin (R).

The liver is the main site of storage of vitamin B12 in the human body (R). Humans obtain vitamin B12 through dietary sources, fortified foods, and supplements (RR1R2).

It can take the form of cyano-, hydroxyl, methyl, and deoxy adenosyl- cobalamin (R).

Cyanocobalamin, the most stable and unnatural form of vitamin B12, is most commonly used in supplements and does not have a direct cofactor role in cellular metabolism.

The most biologically significant forms of vitamin B12 are methylcobalamin and coenzyme B12 (5’-deoxy-5’-adenosylcobalamin) (R1 R2).

Vitamin B12 was considered as the “Painkilling vitamin” in some countries in the 1950’s (R).

The Vitamin B12 That I Recommend

There are a few forms that people can take, depending on what they’re looking for:

Health Benefits of Vitamin B12

1) Vitamin B12 is an Effective Analgesic

Methylcobalamin, a form of Vitamin B12, reduces the clinical symptoms in legs such as paresthesia (an abnormal sensation like tingling or pricking), burning pains and spontaneous pain (R).

In one study spontaneous pain, allodynia, paresthesia of patients with neck pain were improved significantly in the Methylcobalamin group (R).

Intramuscular cobalamin injection is effective in alleviating low back pain in patients with no nutritional deficiencies (R).

Cobalamin provides effective pain management for mouth ulcers (R).

Methylcobalamin treatment reduces pain symptoms in neuralgia, diabetic neuropathy, and lower back pain (RR1R2).

Methylcobalamin improves neuropathic pain (RR1R2R3).

2) Vitamin B12 is Essential for the Brain


Methylcobalamin (MeCbl) is the most effectively taken form of vitamin B12 in neuronal organelles (R).

Cobalamin may have a role in the prevention of disorders of brain development, mood disorders, and Alzheimer’s and vascular dementia in elderly (R).

Supplementation of cobalamin is useful in neuronal regeneration. It also repairs the negative effects of ischemia on neurons (R).

A study on rats with sciatic nerve injury supports the treatment of peripheral nerve injury with Cobalamin (R).

It also increases regeneration of axons and promotes neuronal repair (R1R2R3).

3) Vitamin B12 Improves Sleeping Patterns


Cobalamin treatment improves sleep-wake rhythm disorders in human subjects (RR1).

It may increase the light sensitivity of circadian rhythms due to decreased melatonin levels (R).

4) Vitamin B12 Reduces Depression


In a randomized trial performed on patients with depression and low normal cobalamin levels cobalamin supplementation improved depressive symptoms (R).

5) Vitamin B12 is an Anti-inflammatory

Methyl B12 suppresses cytokine production of T lymphocytes in cells and is speculated to do the same in patients with rheumatoid arthritis (R).

6) Vitamin B12 for the Skin

Topical cobalamin is a new therapeutic option in atopic dermatitis. It is well-tolerable and has low safety risks for both adults and children (RR1).

7) Vitamin B12 has Positive effects in Pregnancy and Lactation


One randomized clinical trial states that oral cobalamin supplementation with 250 μg/day throughout pregnancy and early lactation elevates maternal, fetal, and breast milk vitamin B12 levels (R).

Sources of Vitamine B12


Vitamin B12 Deficiencies

Patients with type 2 diabetes mellitus (T2DM) who are prescribed Metformin, may be at risk for cobalamin deficiency (R).

Maternal cobalamin deficiency is associated with infertility and recurrent spontaneous abortion (R).

Infants born to cobalamin deficient mothers or receiving deficient amounts of animal-sourced foods are  susceptible to deficiency between the ages of 6-12 months (R).

Hormonal birth control (oral contraception and DMPA) usage among female subjects reduced B12 levels (R).

Cobalamin deficiency causes hyperhomocysteinemia, which is a proven risk factor for cardiovascular disease (R).

Individuals with cobalamin deficiency have a higher prevalence of cardiovascular risk factors such as heart failure, a history of transient ischemic attack, and diabetes mellitus (R).

Deficiency of cobalamin inhibits melanin transfer between melanocytes and keratinocytes, which may cause hyperpigmentation of the skin.

19% of subjects in one clinical trial manifested skin hyperpigmentation resulting from cobalamin deficiency (RR1).


  • Genes (notably TCN2) related to cobalamin deficiency may determine clinical manifestations of autoimmune gastritis (R).
  • Cobalamin is an indirect precursor (by methionine production in one-carbon metabolism) of the production of  (SAM), a universal methyl donor (RR1R2R3R4).
  • Cobalamin facilitates the conversion of methyl malonyl coenzymeA (MMA) to succinyl-CoA (R).
  • Histamine 2 receptor antagonists (H2RAs), may lead to malabsorption of food-bound cobalamin due to inhibited b12 cleavage from dietary proteins (R R1).
  • A gene variant CblD (Cobalamin D) is currently speculated to be responsible for the branching of the cobalamin metabolic pathway to the mitochondrion (R).
  • TCII-B12, a cobalamin transport protein, delivers cobalamin to the mitochondria where it is used for the production of MMCoAM, a mitochondrial enzyme (RR1).
  • Allodynia is a clinical feature of many painful conditions, such as neuropathies, complex regional pain syndrome, postherpetic neuralgia, fibromyalgia, and migraine.
  • Methylcobalamin increases nerve conduction velocity, myelin regeneration, neuronal regeneration, and inhibiting peripheral pain transmission (RR1R2R3).

Vitamin B12 on SelfDecode

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  • Q

    Thank you for such a great explanation! I have pernicious anemia on my father’s side, and Alzheimer’s on my mother’s side. My dad has had 2 heart attacks, and my mom’s mother died of complications related to Alzheimer’s, and is losing her memory herself now, quite rapidly. Unfortunately, she will not take any type of supplement, and will only take something with a “brand name”, i.e. prescription medicine. I have Graves’ Disease myself, and am now supplementing with Methyl B12, as I am deficient, as well as using many other helpful supplements. My mom’s symptoms have increased (memory DECREASED) exponentially in the last 4 months, so I am trying to find a way to convince her to supplement with Methyl B12! She won’t go to a doctor, either… sigh. In any case, I’M taking the stuff! 😉

  • Margaret Hawes

    I was on Metformin for 20 years !

    I have a new Dr thankfully. I was so tired all of the time .
    My blood test came back with serious B12 deficiency + very low Potassium.
    He immediately took me off of Metformin.
    I have been havingB12 injections for the last 5 weeks. I have to continue to have them for once a month for next 5 months.

    I must say I am impressed with vitamin B12. My energy levels are thankfully improving . Pottasium slowly increasing too.

    And not having Metformin anymore after taking it for 20 years my sugar levels are stable .

    I thank my lucky stars I now have a goid Doctor

  • B12

    Thank you, I will try Methylcobalamin

  • Brian Fisher

    Thank you! Great info!

  • Firdosh

    Can I take b12 vitamin 2500 every day

  • Raj

    Thank you very much Peter, excellent sharing of information and it’s very easy to understand… unlike much technical information which is extremely difficult to understand for a common man… Regards

  • Peter Rutkiewicz

    My family has had significant experience with Vitamin B12 deficiency and treatment and the state of current medical profession’s knowledge with the B12 vitamin’s role in health. First,. the current levels of B12 sought in the United States of 200-850 ng/L (pg/ml) are wrong. In Japan, the range is 550 pg/ml and above and any reading below 550 is supplemented. The Framingham Study of 23,000 residents over 20 years found B12 deficiencies in 75% of the elderly population over 80 years old. The long term symptoms of B12 deficiency are subtle, gradual and can do permanent damage to the CNS and particularly to the health of the elderly. B12 must be methylated to be usable by the body and the best way to supplement is with methylated B12 taken sublingually (under the tongue) once a day. You cannot overdose on B12,,,there is no upper limit. My own B12 level is double the normal range in the USA with no ill effects. If you are B12 deficient, you will typically be given a shot and perhaps pills. But the reason you are deficient is almost always due to an absorption problem and attempting to get more B12 through diet as cyanocobalamin will be unsuccessful. I suggest using 5000mcg methylcobalamin sublingually to rebuild your B12 reserves and maintain your health during the rebuilding. The liver is capable of storing B12 and its reserves are used up gradually over many years (a decade or more) which is why symptoms of deficiency come on gradually and are often not recognized or a B12 test ordered to check.

    B12 deficiency in the elderly is often attributed by doctors as “old age” and our seniors don’t get treatment. Poor short term memory, forgetfulness and then dementia are gradual symptoms that the elderly experience as deficiency gets worse. B12 is responsible for the collagen laid down in the bones (deficiency causes brittle bones leading to fractures) and for the principle neurotransmitter norepinephrine (deficiency causes mental problems, dementia and eventually CNS damage to the spinal cord which is not reversible). Also, B12 is important for the conversion of homocysteine (from protein digestion and absorption) into products that the body can use to maintain cellular repair. High homocysteine levels that result from B12 deficiency can cause heart attack and stroke…common diseases afflicting the elderly.

    Some families have an uncommon genetic affliction called “familial pernicious anemia” which causes absorption problems with B12 earlier in life (20 and 30’s) and is often discovered as anemia results in blood tests. Doctors are not familiar with this condition because it appears in less then 1 in several thousand patients and a doctor may only meet one patient in their career who presents with this problem. My family of English/Scottish origin has this anomaly and we have seen several of our older members suffer unnecessarily due to misidentification and inadequate treatment. One the symptoms have begun to appear it is a critical juncture to treat adequately to prevent fractures, memory problems, dementia and an ongoing and worsening assault on health as you age. Methylcobalamin is the only adequate treatment for the elderly. Cyanocobalamin shots produce extremely slow recovery rates, further risking the patient’s health for several years because the elderly cannot methylate it quick enough to make use of it. If you supplement, methylcobalamin is the way to go. If you are deficient, you most likely have an absorption problem, Methylcobalamin taken sublingually every day will produce an immediate improvement in symptoms and keep you from becoming a life long patient with worsening health.

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