7 signs of vitamin b12 deficiency 62bc48fc379f8

7 signs of Vitamin B12 Deficiency

Vitamin B12 deficiency is widespread and more common in strict vegetarians. It is also more common in people with acid suppressing medications, people taking diabetes medications like metformin, and those exposed to glyphosate, a pesticide used in growing wheat. Many people get regular injections of B12. They have reported a number of benefits including noted higher energy levels, better brain function, and weight loss among other experienced benefits.

Vitamin B12 or cobalamin is a water soluble vitamin and is vital to proper brain function, production of DNA, and red blood cells. It is stored in the liver and it can take years for deficiency to develop but that also means can take time to replenish.

Up to ninety percent of people that follow a primarily vegetarian or vegan diet have a deficiency of vitamin B12 as B12 is only found naturally in animal foods. Even people that eat animal products like meat can be deficient due to medications, intestinal surgery especially for weight loss, and diseases like Crohn’s disease. Also people that don’t produce enough intrinsic factor leads to vitamin B12 deficiency which occurs as we age. Studies suggest that up to 20% of people over the age of 60 in the United States and the United Kingdom are deficient in vitamin B12. Still, that doesn’t mean children and younger adults, including those who are pregnant and breastfeeding, can’t develop B12 deficiency.

Consequences of vitamin B12 deficiency include neurological problems, fatigue, and pernicious anemia with reduced amount of red blood cells. Vitamin B12 shots are the most common way to prevent or treat a deficiency. They are given as hydroxycobolamine or cyanocobalamine and are very effective at raising blood levels of vitamin B12.

How do you know if you might be Vitamin B12 deficient? You can have a “normal level” of B12 on a blood test but still not have adequate amounts in the cells which is difficult to measure. For reference, B12 levels above 300 pg/mL are considered normal, levels of 200–300 pg/mL are considered borderline, and levels below 200 pg/mL are considered deficient

B12 typically is absorbed through the gastrointestinal tract but if you lack acid or intrinsic factor, have inflammation from bacterial or yeast imbalances, or damage from toxins or pesticides like glyphosate you may not be able to absorb B12. Also, some people have genetic variations in the MTHFR gene and may require B vitamins that are readily useable in the methylated form of vitamin B.  For all these reasons, people with vitamin B12 deficiency improve significantly with vitamin B12 injections.  

Here are 7 common symptoms of low Vitamin B12.

  1. Fatigue

If you’re low or deficient in B12, you’ll feel fatigued.

Inadequate  B12 levels can decrease normal red blood cell production, which can impair oxygen delivery

A deficiency in B12 or folate can cause megaloblastic anemia. This condition leads to the formation of large, abnormal, and immature red blood cells and impaired DNA synthesis

You can develop fatigue and other symptoms related to B12 deficiency, even when your B12 levels are considered within range or only borderline low.

  1. Skin Pallor

Another sign that can indicate B12 deficiency is pale or yellow skin.

Similarly, to iron deficiency anemia, anemia related to B12 deficiency may make your skin pale due to a lack of fully-matured, healthy red blood cells in the body

  1. Headache

B12 insufficiency and deficiency can lead to neurological side effects, including headaches.

It is the most commonly reported symptoms related to B12 deficiency in both adults and kids.

A 2019 study with 140 people, half of whom experienced migraines, found that blood levels of B12 were significantly lower in the participants with migraines compared with the participants with no migraine history.

The study also found that those with the highest B12 levels were 80% less likely to have migraines compared with participants with the lowest B12 levels.

  1. Feeling Depressed

B12 is essential to the proper functioning of your central nervous system, and a deficiency in this nutrient can impact your mental health.

B12 deficiency is associated with a greater risk of developing depression.

Having low levels of B12 can cause elevated levels of homocysteine. In turn, this may contribute to the development of depression by increasing oxidative stress, DNA damage, and cell death in the body.

A 2020 study with 132 children and teens, 89 with and 43 without depression, found that the participants with depression had lower B12 levels and higher levels of homocysteine compared with those without depression.

Other symptoms of low or deficient B12 levels may lead to other mental conditions, including psychosis and mood disorders.

  1. Oral and Gastrointestinal issues 


B12 Deficiency can result in glossitis is a medical term that refers to an inflamed, red, and painful tongue.

In people with this deficiency, glossitis can appear alongside stomatitis, which is characterized by sores and inflammation in the mouth.

Glossitis can also be caused by deficiencies in other nutrients, like folate, riboflavin (B2), and niacin (B3).


A B12 deficiency may also cause diarrhea, nausea, constipation, bloating, gas, and other gastrointestinal symptoms.

Many of these symptoms are non-specific and could be caused by other factors. For example, food intolerances, medications, and infections could all lead to diarrhea.

  1. Difficulty with focus and cognitive executive function

People with low or deficient B12 levels may feel foggy-headed and have difficulty concentrating and completing tasks because a deficiency in B12 negatively impacts the central nervous system

Older adults are especially at risk for these side effects because the risk of B12 deficiency increases with age.

Studies show that mental impairment related to low B12 levels can improve with B12 treatment.

A 2020 study gave 202 people with mild mental impairment and low or low-normal B12 levels and elevated homocysteine levels B12 replacement therapy for 3 months.

After the treatment, 84% of the participants reported significant improvements in symptoms, like poor focus, memory decline, and forgetfulness.

  1. Paresthesia in hands and feet

Paresthesia is a medical term that refers to a burning or pins-and-needles sensation in certain areas of the body. Most commonly this is noticed in the hands and feet.

Many adults and kids who have B12 deficiency report experiencing paresthesia.

This symptom of B12 deficiency overlaps with symptoms related to diabetic neuropathy or nerve damage caused by high blood sugar that can cause pain and numbness in the extremities

Metformin, a common drug for people with diabetes leads to a higher risk of developing B12 deficiency, because this medication can reduce vitamin B12 absorption in the body.

As a result, many experts recommend that people taking metformin regularly get screened for vitamin B12 deficiency.

Other signs and symptoms of B12 deficiency 

In addition to the symptoms above, B12 deficiency may lead to the following:

  • Muscle cramps and muscle weakness. B12 deficiency affects sensory nerve function leading to motor dysfunction, which can cause muscle cramps and weakness
  • Impaired coordination.  Ataxia, or impaired balance and coordination, is a neurological symptom that can be caused by B12 deficiency. B12 deficiency may result in a person having difficulty walking and balancing
  • Erectile dysfunction. Men with B12 deficiency may experience erectile dysfunction as a result of increased levels of homocysteine in the body
  • Vision disturbances. B12 deficiency may cause vision disturbances, possibly due to damage to the optic nerve

How do you detect and treat B12 deficiency?

Because vitamin B12 deficiency symptoms aren’t specific to the condition, it may go undetected or get misdiagnosed.

Evaluation for vitamin B12 deficiency is recommended if you have some of the above mentioned symptoms and you have lifestyle or other risk factors like the following.

This is especially relevant if you:

  • follow a restrictive diet, like a vegan diet
  • are over the age of 60
  • are pregnant or breastfeeding
  • have a medical condition that can deplete B12 levels
  • take a B12-depleting medication, like metformin or proton pump inhibitors

Laboratory studies that can be checked:

  • B12 levels
  • folate levels
  • a complete blood count (CBC) with a peripheral smear
  • methyl malonic acid (MMA) levels
  • homocysteine levels

An appropriate treatment for low or low normal vitamin B12 levels may include B12 injections. Oral B12 supplements may also be considered. There is a need to address underlying health conditions that could be causing the deficiency.

B12 injections are definitely recommended for people who can’t properly absorb B12 from food or supplements, like those who’ve undergone gastric bypass surgery or people with certain autoimmune diseases and is the most effective and efficient way to restore B12 levels.


In Summary

B12 deficiency can cause a variety of symptoms, including fatigue, headaches, depression, skin pallor, mental impairment, and pain and inflammation in the mouth and tongue.

Many of the symptoms caused by low B12 levels are not specific to B12 deficiency, which can cause the condition to go undetected.

If you’re experiencing any of the symptoms listed above, it’s important to get an evaluation and undergo appropriate testing and get the right treatment.

B12-rich foods include fish and shellfish, organ meats, and eggs

If you follow a vegan or vegetarian diet, you can add B12 fortified foods, like nutritional yeast and plant milk, and taking a B12 supplement can help you maintain optimal levels.


Here at All Functional Health we are providing subcutaneous and intra muscular injections with our shot bar services. In addition to personalized B12 formulation injection like Energy with methylated B12 to boost energy, improve brain focus, help burn fat. We have other tailored shots such as:  Skinny Weight Loss Peptide cocktail with MIC/B complex to metabolize fat to energy, liver detox, and remove heavy metals; amino blend to support nitric oxide, strengthen connective tissue, improve fat metabolism, decrease exercise recovery time; Energy Fountain with glutathione for oxidative stress, detoxify, promote immune balance; Hair Repair with B12, biotin, and Glutathione.  Stay tuned for future blogs on these specialized formulations tailored made for you.  We’ve helped thousands of people on their journey of health and look forward to helping you. Please contact us at info@jeffreymarkmd.com, schedule a consultation at www.allfunctionalhealth.com, or call (925) 736-9828. Take Care and stay healthy.


Jeffrey Mark, M.D.

Jeffrey Mark, M.D.

Helping clients with compassionate and comprehensive medical care for over 25 years with 4 board certifications in functional medicine, gastroenterology, internal medicine, and anti-aging/ regenerative medicine . IFMCP, ABIM Gastroenterology, NPAS Internal Medicine, ABAARM.

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