How Long to Recover from Vitamin B12 Deficiency?

The question is, “How long to recover from vitamin B12 deficiency?” Many factors are involved, but it generally takes six months to 1 year to recover from vitamin B12 deficiency. 

What Is Vitamin B12?

Vitamin B12, also called cobalamin,is one of the eight B vitamins that we need to keep our bodies running. It helps with many things, including red blood cell production, nerve function, and proper digestion.

The body itself does not make vitamin B12. Instead, it must be obtained from food sources like meat and dairy. 

How Long to Recover from Vitamin B12 Deficiency
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Some people cannot get enough vitamin B12 from their diet alone, so they must take supplements or eat fortified foods like cereal or nutritional bars.

How Does the Body Absorb Vitamin B12?

So, first up, our stomach comes into play with its mighty hydrochloric acid, breaking up Vitamin B12 from the protein it’s chilling with. 

Then, B12 travels through your bloodstream until it reaches its target cells, at which point it enters them by binding itself to receptors on their surface called intrinsic factors (IFs). 

If the IFs recognize that no free B12 molecules are floating inside the cell, they grab the incoming B12 molecules tightly and escort them into its interior, where they can do their job. 

If vitamin B12 is coming from supplements, it’s already flying solo, and our body welcomes it with open arms. 

However, vitamin B12 bound to protein in food passes through an initial separation reaction before the body can absorb it. 

When the Body Cannot Absorb Vitamin B12

Absorption of vitamin B12 is dependent on the stomach’s ability to produce intrinsic factors, a substance that binds with the vitamin and allows it to be absorbed in the small intestine. 

In some cases of malabsorption, there may not be enough intrinsic factors produced by the stomach or enough acidity in the stomach to allow for proper binding.

If this happens, vitamin B12 will pass through your digestive tract without being absorbed. Consequently, your body becomes deficient in vitamin B12. 

What Is Vitamin B12 Deficiency?

Vitamin B12 deficiency is a condition in which the body doesn’t have enough of this vitamin. Without enough vitamin B12, your body may have trouble making red blood cells and keeping your nervous system healthy.

Anyone can be deficient in vitamin B12. However, it’s more common among vegetarians or vegans, older adults, pregnant women, and people with certain health conditions, including Crohn’s and celiac diseases.

Causes of Vitamin B12 Deficiency

Vitamin B12 deficiency happens when you’re getting enough of the vitamin in your diet or by having a condition that prevents your body from absorbing it. Some common causes of B12 deficiency include:

  • Vegetarianism
  • Crohn’s disease and other inflammatory bowel diseases
  • Celiac disease
  • Chronic diarrhea
  • Pancreatic disorders
  • Liver disease
  • Alcoholism 
  • Eating disorders like anorexia nervosa or bulimia nervosa.

Symptoms of Vitamin B12 Deficiency

Signs and symptoms of a disease are the same, but they’re usually used in different contexts.

Signs are usually defined as symptoms that you can see, like a rash, or something that you can measure, like body temperature. They are often used to diagnose diseases.

For example, if your doctor sees a rash and knows that it’s associated with Lyme disease, then she can diagnose you with Lyme disease based on the sign (rash).

Symptoms are more subjective: they’re things you feel inside yourself. For example, if you have a fever and start feeling nauseous and dizzy, that could be a symptom of an illness. It might indicate that your body is fighting off an infection or virus.

If you experience the following symptoms, you may be cobalamin deficient: 

  • Fatigue
  • Weakness
  • Numbness around the mouth or tongue
  • Constipation
  • Depression
  • Confusion
  • Memory loss
  • Dementia
  • Weight loss due to muscle wasting rather than fat loss (atrophy)
  • Psychosis (loss of contact with reality)
  • Paranoia (extreme distrust of others)
  • Tingling or numbness in fingers or toes, called paresthesia.

How to Detect Vitamin B12 Deficiency

To evaluate for Vitamin B12 deficiency, a complete blood count (CBC) and serum Vitamin B12 level test are recommended.

The CBC test is used to determine the number of red blood cells and platelets in your bloodstream. It also shows how well your bone marrow is working. If this test shows that you have low red blood cell counts or low hemoglobin levels, it can indicate vitamin B12 deficiency.

The serum vitamin B12 level test measures how much Vitamin B12 is in your blood. If this test shows you have low levels of vitamin B12 (lower than 150 pg/mL), an injection of high-dose vitamins may be needed to treat the deficiency.

However, a serum vitamin B12 level test may not always be a reliable indicator of deficiency, and additional testing may be required. 

In such cases, a serum methylmalonic acid (MMA) level or holotranscobalamin (holoTC) level may be used to confirm Vitamin B12 deficiency when the serum Vitamin B12 level is normal or low-normal. 

MMA is a substance that accumulates in the blood when Vitamin B12 levels are low. Holotranscobalamin testing assesses the level of transcobalamin circulating in the blood that is directly available to cells.

Treating Vitamin B12 Deficiency

We can treat vitamin B12 deficiency by taking large doses of the vitamin.

You may need more than one injection daily, but this will decrease as your body stores more vitamin B12 in its tissues and needs less new supplementation.

If you are concerned about your vitamin B12 levels, talk to your doctor about the treatment options available to help you optimize your health. 

Oral B12

The most common way to treat vitamin B12 deficiency is through oral supplements. This form of treatment is suitable for those who have low levels of the vitamin in their body but not those with pernicious anemia.

You’ll want to talk to your doctor about how much and how often to take these supplements to avoid overdosing on vitamin B12. 

Intramuscular B12

A healthcare professional gives intramuscular injections into the muscle. They can be painful, so know what to expect before your appointment.

Subcutaneous B12

Subcutaneous administration of B12 is the best option for patients who cannot or choose not to take oral supplements or those who have difficulty absorbing other types of vitamin B12.

The most common method is to inject it into the fatty tissue just under your skin (subcutaneous). 

Intravenous B12

Another way to get B12 is through an IV. You can receive this treatment in a hospital or outpatient setting, from a doctor or nurse. It can also be done at home using self-administered kits, but these are not FDA-approved for use as a substitute for medical care.


The best way to treat vitamin B12 deficiency is with a daily supplement containing the recommended amount of B12. If you cannot take a supplement, you should talk to your doctor about getting injections or sublingual tablets.

Vitamin B12 deficiency has no overnight cure, but we can prevent and treat it with proper diet and supplementation.