Vitamin B12 levels: normal range (table, by age) (2023)

Want to see if your B12 levels are normal? We often get questions like,“My B12 is 201, is it low? That's within my clinic's normal vitamin B12 range chart!”. Readers sometimes ask for a specific chart listing normal B12 levels by age. Sometimes they askideal B12 levels for women, men or children. Let's clear up the confusion.

First, keep in mind that a whole blood vitamin B12 test doesn't tell us as much as people think. This is due to several reasons:

  • In most countries, the low range of what is considered normal blood levels of vitamin B12 is very low (100-250), often lacking in people who are desperately deficient. people showSymptoms of B12 deficiencyeven at higher levels, as damage begins to occurappear in the cerebrospinal fluid below 550. This is why Japan treats anyone with levels below 500 withB12 injections. These are levels that are considered normal in the US and most of the rest of the world. While 200 is often accepted as a low normal value that does not require intervention, Japan and England have updated their suggested range with values ​​of only 500-550 and consider anything lower to be dangerous.
  • B12 whole blood test is unreliable. It measures the total amount of B12 in the blood, it does not distinguish between active and inactive forms of B12. Inactive analogs of vitamin B12 (transcobalamin I and III) can representdo 90%blood levels. If a significant amount of vitamin B12 is inactive, a test can show that you have normal levels of vitamin B12. That's why Japan and England updated their maps. Depending on the number of inhabitants,30-50% of patients with B12 deficiency (as measured by actual and low levels of active B12) will have "normal" total B12 levels of 150-300.

In short, you can't rely on a regular serum B12 test to tell you the whole story. You can only use it as an indicator. Now, let's show some actual graphs.

Vitamin B12 levels: normal range (table, by age) (1)

Normal levels of vitamin B12

In most countries, normal values ​​of vitamin B12 have been observed - both in children and in adults, men and womenwomen– are between 100 and 1400 pg/ml. These observed levels vary from one culture to another. Dr. Ralph Carmelreportedthat blacks have significantly higher levels of B12 (espactive levels of B12) than Caucasians, while the lowest levels were recorded in India, Africa and Pakistan. This may be due to racial differences in vitamin B12 metabolism or social factors –most obviously nutrition. Probably both.

Let's take Konya in Turkey as an example and compare it to other places. We will look at children and adolescents, because we have a lot of information about that.

Normal B12 levels by age – Konya, Turkey

let's lookthis study from Turkey, which measures the level of vitamin B12 according to age (0 to 24 years). In particular, look at the mean levels (middle column) and the full range measured in each percentile group (three columns on the right):

Vitamin B12 levels: normal range (table, by age) (2)

As you can see, the range of B12 levels in children and adolescents under 18 is approximately 100-700. Now compare with children from other parts of the world:

Vitamin B12 levels: normal range (table, by age) (3)

Clear differences.

Although, as you can see, American children aged 13-18 have B12 levels similar to Turkish children in Konya. If England and Japan have updated their low threshold to 500-550, does that mean most of these children are deficient in vitamin B12? Not necessarily, becausemany people with traditionally normal levels of 300-400 have elevated levels of active vitamin B12and they are not disabled. The new higher values ​​are set as a precaution.

The new normal chart of vitamin B12 levels

Again, total blood levels of vitamin B12 are wildly inaccurate and many people are deficient even when they show what many places consider to be normal levels of vitamin B12. The new ranges for Japan and England are similar to the B12 level chart proposed by Sally M. Pacholok and Jeffrey J. Stuart in their bookCould it be B12?An epidemic of misdiagnosis:

Status B12levels of B12(pg/mL)
Normal> 550
A healthy nervous system and disease prevention in the elderly> 1000

To quote Sally and Jeffrey:

At this time, we believe that normal serum B12 levels should be greater than 550 pg/ml. For brain and nervous system health and to prevent disease in the elderly, serum vitamin B12 levels should be maintained at or above 1000 pg/ml.

The tragedy lies in all those people who have symptoms but are in the low range of normal vitamin B12 levels (200-500). That's itgray zone, and although these people show clinical signs of vitamin B12 deficiency, they are never tested or treated because their vitamin B12 is within the accepted range of vitamin B12 levels. This results in a late diagnosis (if any) and a higher incidence of neurological damage. So don't rely on blood tests alone.

observing:If you know you are deficient and want to quickly replenish your B12 supply, now you canorder a bottle of B12 injection here. We are finally making it available 🙂

Order a B12 injection

Finally, how do you actually test for B12 deficiency?

How to check a healthy B12 level?

There are three ways to know if you have good B12 levels or not.

Methylmalonic acid (MMA)

Vitamin B12 helps convert methylmalonyl-CoA, one form of MMA, to succinyl-CoA. When you are deficient in vitamin B12, MMA levels rise in both blood and urine. You can find the MMA test in hospitals or private laboratories.

If you can't find it, you can order an MMA urine analysis atDr., founder of the test. The uMMA test is even better than the serum MMA test because vitamin B12 deficient patients with neurological damagesecrete significantly more uMMA than those without damage. Therefore, uMMA testscan predict the path to permanent neurological damage. The test is impressive99% accuracy, which makes it affirmative.

Note that if you have kidney disease, you may get falsely high levels with the serum MMA test or falsely low levels with the uMMA test. This is because the kidney's function is to excrete MMA in the urine. If they don't work properly, MMA can build up in the blood. Serum levels of MMA may also be elevated in patients with thyroid disease or small intestinal bacterial overgrowth. It can also be elevated in pregnant women or children who have a rare genetic condition called methylmalonic acidemia.

However, if your uMMA levels are high, you are probably suffering from a vitamin B12 deficiency. This is as much confirmation as avitamin B12 deficiency testcan get.

Holotranskobalamin (HoloTC)

Another useful test isholotranscobalamin (holoTC) assays, which registers only the active form of B12 in the blood. Available inViapath.This test is intended as a first diagnostic tool. Low levels may indicate a vitamin B12 deficiency at the cellular level.

We anticipate that this test will one day replace the current test, as there are often very large differences between total B12 and active B12 in the blood.


Another useful tool to assess your actual B12 status is to measure total homocysteine ​​(tHcy). Methyl B12 is needed as a cofactor to convert homocysteine ​​back to methionine. If you have normal vitamin B12 levels but elevated homocysteine ​​levels, this could indicate a deficiency or problem utilizing methyl B12. However, elevated homocysteine ​​levels can also result from low levels of vitamin B6, folic acid, kidney failure, or hypothyroidism.

The above testswill help you get the correct diagnosis.. We also recommend folate and ferritin (iron storage) testing and a complete blood count, as B12 and folate need each other, and optimal iron levels are just as important as optimal B12 levels.

trust the symptoms

To quote FAIL:

In the event of any discrepancy between the clinical results of vitamin B12 deficiency and a normal laboratory finding of vitamin B12, treatment should not be delayed. Clinical findings may include possible pernicious anemia or neuropathy, including subacute combined degeneration of the spinal cord. We recommend storing the serum for further analysis, including MMA, or holotranscobalamin and intrinsic factor antibody analysis, and treating the patient immediately with parenteral vitamin B12 therapy.

UK National Quality Assessment Scheme for Haematin Assays

If you suspect that you may be suffering from a vitamin B12 deficiency, take immediate action. Ignore vitamin B12 blood levels and only consider symptoms, as the risk is very high. Wait too long and permanent neurological damage can occur.

Remember,you cannot overdose on B12. And maybe that's why Japan likes to inject every patient with a level below 500. The risk is zero for those who don't have B12 deficiency, and the potential risk of not injecting for those who do is huge.

The sooner you starttreatment, the more likely you are to avoid damage. Early treatment can sometimes completely reverse symptoms. But there is a small window of opportunity for effective intervention, especially for those withneurological symptoms.

When you suffer from vitamin B12 deficiency, the myelin sheath that surrounds your nerves is removed. If you have any symptoms, especially neurological ones, thenstart injecting methyl B12. These photos are the best way to quickly restock stores. Do this for at least three months, as this is the life cycle of red blood cells. Only after 90 days will you have all your bad cells replaced by healthy cells.

Then see how you feel.

Good luck.


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