Why Is My B12 So Low?

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The Pure TheraPro Team

The Pure TheraPro Education Team is comprised of researchers from diverse backgrounds including nutrition, functional medicine, fitness, supplement formulation & food science. All articles have been reviewed for content, accuracy, and compliance by a holistic integrative nutritionist certified by an accredited institution.
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“Why is my B12 so low?” Is this a question you’re asking right now? You’re not alone, particularly if you’re over the age of 60. It is estimated that in the United States, approximately 20% of seniors are low in vitamin B12. 

It’s not just an age thing, though. With the growing number of autoimmune diseases and gut absorption issues, rates of nutrient deficiencies such as B12 deficiency are on the rise. According to a study, women, non-Hispanic blacks and people of low socioeconomic status are at greater risk of vitamin B12 deficiency. 

Optimal B12 levels are important to your health. Vitamin B12 protects both DNA and RNA, provides you with energy, protects your nerve and brain cells, helps regulate serotonin levels, assists with red blood cell formation, supports your immune system and helps regulate your mood. Many with low levels of B12 suffer from depression and anxiety, insomnia, poor immune function, gut issues, brain fog, neuropathy, cardiovascular issues, chronic fatigue and more.


So, what might be the reasoning behind your low levels of B12?

Here are some of the main causes:


Pernicious Anemia:

Pernicious anemia is thought to be an autoimmune disease which affects the body’s ability to absorb and utilize B-12 due to a deficiency of a substance known as intrinsic factor that is normally produced by the parietal cells in the stomach. Intrinsic factor is necessary for vitamin B12 absorption.   

Those with pernicious anemia can’t absorb B12 from food, so options include B12 injections or high dose sublingual supplements, such as our BioActive B12.



Most B12 injections are in cynocobalamin form. Even B12 injections with methylcobalamin, however, many contain harmful adjuvants, so request the package insert if you’re considering B12 injections and learn more about the various forms of B12 to select the proper one for your individual needs.


Malabsorption Issues:

Low levels of B12 might be an indication of malabsorption issues not related to intrinsic factor, such as low stomach acid. Without ample amounts of stomach acid, food can’t be properly digested, meaning that the nutrients from food aren’t readily absorbed. This is usually due to a combination of factors, such as a deficiency in digestive enzymes, gut flora imbalance, slow digestion due to a metabolic issue or even a parasitic infection. Nutrient deficiencies as a result of low stomach acid are common with thyroid issues, such as Hashimoto’s or hypothyroidism. 


Microbiome Dysbiosis:

SIBO, which frequently accompanies hypothyroidism, may also affect nutrient absorption. An overgrowth of bacteria in the small intestine has been shown to cause vitamin B12 deficiency in studies conducted by the University of Virginia School of Medicine. The bacteria actually compete with our bodies for valuable B12, literally stealing it from us for their own use as energy, which leaves us deficient. Eliminating SIBO and reducing the related gut inflammation may help improve nutrient absorption and is the first step in creating microbiota balance. Maintaining good bacteria in the gut can help maintain this balance. 


Low Thyroid Levels:

It is estimated that about half of patients with Hashimoto’s or hypothyroidism also have nutrient deficiencies, which include B12 deficiency. 

Low levels of thyroid hormone resulting in an impaired metabolism does affect the digestive system. Everything slows down making it difficult for the body to properly absorb nutrients. 

Low levels of iron are also associated with hypothyroidism, resulting in anemia. The body’s inability to carry oxygen effectively via red blood cells as a result of anemia can further complicate absorption of B12. Other common nutrient deficiencies associated with low thyroid levels include iodine, zinc, selenium, glutathione and vitamins A, E, D as well as B. Ferritin levels, which are the stored iron levels in the body, may drop, resulting in chronic fatigue and hair loss. All of these nutrients are instrumental in health and wellness and the depletion can impact multiple systems and affect the absorption of other vitamins, minerals and nutrients. 

Patients with hypothyroidism or Hashimoto’s in the western medical system may be prescribed pharmaceuticals that further deplete the body of nutrients or block the absorption of nutrients. These may include synthetic hormone replacement including birth control pills, proton pump inhibitors to manage GERD, antibiotics and antifungals for chronic infections associated with low thyroid levels. 



It is hypothesized that our guts may sustain damage from eating GMO foods. These genetically modified organisms contain insect-killing proteins. Their method of action is that they attack insects’ guts like a machine gun. Since GMOs introduction into our food industry, many people have complained of a variety of gut-related and systemic issues, such as food allergies, gluten intolerance, Leaky Gut Syndrome, IBS, Crohn's Disease and a startling increase in autoimmune diseases. Autoimmune diseases affect approximately 8% of the population (23.5 million Americans) and the numbers are rising. All of these issues can contribute to nutrient malabsorption. This is why it’s so important to only eat organic. 



Vegans and vegetarians are more at risk of B12 deficiency since vitamin B12 is solely found in animal proteins. This is why it is essential for vegans to supplement with a highly bioavailable source of B12. 

While those with autoimmune diseases such as Hashimoto’s may benefit from a gluten free diet, the elimination of enriched grains may require additional B vitamin supplementation. Most with autoimmune diseases also have methylation issues or MTHFR and will find that methylated forms of B vitamins, which are more readily utilized by the body, are better choices than synthetic forms. 



Our Methyl B Complete contains a compilation of methylated B vitamins and nutrients that help regulate homocysteine levels, promote proper energy and cellular detoxification and optimize methylation. 


Vitamin B12 and folate work together in the body for many functions, such as helping balance homocysteine levels. Both nutrients assist with synthesizing melatonin, allowing you to get a good night’s sleep. Optimal levels of B12 AND Folate have also been shown to be protective against cognitive decline.



Our BioActive B12 is a high-quality VEGAN vitamin B12 complex utilizing three bioavailable forms: Methylcobalamin, Hydroxocobalamin and Adenosylcobalamin.

This advanced formula includes ingredient forms that need no conversion in the liver in order to be available for use by your cells. As a sublingual supplement, BioActive B12 provides maximum absorption through the mucous membranes in the mouth. Just 4 drops equal 4000 mcg of B12.


Have questions about which supplements might be the right fit for you?

Please reach out to us: info@purethera.com

or give us a call: 888-655-4648 (M-F, 9-5 PM, MST).