All About B12 Injections

By Natalie Ledbetter CRNA, DAcOM

B12 is a water-soluble vitamin that is important in many functions in the body. Without it, the body cannot function properly and can suffer permanent damage. Supplementing B12 in instances of deficiency can reverse many negative symptoms and can prevent permanent damage if it has not already occurred. B12 can be taken orally but does not absorb properly in many instances. In these cases, B12 can be administered by injections and is instantly in the blood stream ready to assist the body.

B12 is necessary for red blood cell formation and a deficiency can cause a condition called pernicious anemia. It is needed for nerve cell health and neurologic function, helping to make and maintain the myelin sheath that surrounds and protects the nerves. It helps with the proper function and development of the brain and nerve cells. B12 is required for proper energy metabolism in the mitochondria and helps sustain metabolism.

With all of these important functions, it is easy to see how low levels of this important vitamin can cause or contribute to many unwanted symptoms. Many can be reversed with supplementation, but chronic deficiency can lead to permanent neurological complications.

Common symptoms of B12 deficiency include:

Memory and learning problems

Lethargy and fatigue




Heart Palpitations

Sore tongue or mouth ulcers

Tingling in hands and feet


Food sources particularly high in B12:

Organ meats



Beef or buffalo


Who is at increased risk of having low B12 levels?

Many medications and gastrointestinal problems interfere with B12 absorption from the gut. People with diabetes and thyroid issues, smokers, older adults, and vegans and vegetarians are at an increased risk for lower levels.

Medications that can lower B12 levels include:


Some antibiotics

Anti-seizure medications



Conditions that increase risk for deficiency:

Older age

Crohn’s disease

Irritable Bowel Syndrome (IBS)

Celiac disease

History of gastric bypass, gastric stapling, or any weight loss surgery involving the GI system

Vegetarian/Vegan diet (as much as 90% of vegans are low in B12 if they do not supplement)

Abusers of alcohol



People on the medications listed above

B12 shots
                                           B12 shots work quickly to increase B12 levels

What form of B12 injection is best?

There are two forms of B12 that are most commonly used to supplement- methylcobalamin and cyanocobalamin. Cyanocobalamin is a synthetic form of B12 and methylcobalamin is a naturally occurring form that can be found in food sources such as fish, meat, eggs and milk. Because cyanocobalamin has to be converted into an active form in the body, not everyone can benefit from this version. Some people have problems methylating substances (adding a methyl group) and so can’t convert other forms of B12 into methylcobalamin which is the form the body uses. Methylcobalamin also remains in the body longer so it is a more effective form of B12. We only use this form of B12 in our clinics and do not charge more for it even though it is a more expensive supplement.


Benefits of B12 injections

The benefits of having adequate B12 levels are many and the risks of B12 injections are extremely rare. Any excess is stored in your liver and once the liver has enough the rest is filtered and discarded by the kidneys. Because of this it is generally considered safe. Even at high doses research suggests that it is practically impossible to overdose. An allergic reaction can occur, but is rare.

Only about 2% of an oral supplement of 500mg is absorbed, and that is if the pH of the GI tract is not altered by medications or other ingested substances. Injections of B12 whether intramuscular, subcutaneous, or intravenous bypass the GI tract and are readily absorbed.

B12 injections treat and avoid or decrease the risk of complications related to B12 deficiency. Proper levels are required for optimal energy production in the mitochondria and help sustain the metabolism. Supporting metabolism and energy production helps increase energy levels and may assist in achieving or maintaining proper weight.

Methylcobalamin (not any other form of B12) benefits sleep by helping to improve the circadian rhythm because of its relationship to melatonin. It works on the pineal gland increasing the production of melatonin at night and causing it to be released earlier making it easier to fall and stay asleep.

A quick review of the benefits of B12 injections

Ease of absorption with higher blood levels than an oral supplement

Decreased risk of or treatment of pernicious anemia

Increased energy

Increased metabolism

May help with weight control

Positive effects on mood

Promotes brain and nerve cell health

Supports memory and learning

Improved sleep

If you are feeling tired or foggy in the head, want metabolic support, or suspect you may not be getting enough B12, call one of our Austin area offices and pop in for a quick B12 (Methylcobalamin) injection.


Interested in more information about other vitamins to support health?

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