Vitamin B12 Injections

Vitamin B12 was first discovered as a cure for pernicious anemia in 1926, but the use of vitamin B12 injections as a means of supplementation didn’t begin until much later.

Liver juice, the ancestor of vitamin B12 injections

Historically, pernicious anemia was always fatal, hence the name. People suffered early symptoms like fatigue, memory loss, and muscular weakness without knowing that low vitamin B12 levels were to blame. Death was inevitable.

One day, Dr. William B. Castle discovered the existence of the digestive enzyme intrinsic factor, while he was in the process of feeding regurgitated raw hamburger meat to patients of pernicious anemia, noticing the absence of this essential protein for digesting vitamin B12.

In 1926, scientists started using raw liver juice as a means of supplying vitamin B12 to people with pernicious anemia. It wasn’t until 1948 that scientists isolated cobalamin as the essential nutrient for preventing pernicious anemia, and started prescribing vitamin B12 injections as treatment, noting that while consumption of oral doses of vitamin B12 were ineffectual for reducing symptoms like extreme fatigue and absentmindedness, prompt administration of vitamin B12 injections produced more significant results.

What is pernicious anemia?

Pernicious anemia is a type of megaloblastic anemia, meaning that it affects the size and shape of your red blood cells. Unless you supplement with vitamin B12 injections, you run the risk of severe red blood cell depletion, as vitamin B12 is crucial for proper cellular development.

Causes of pernicious anemia include autoimmune disorder and stomach damage from chronic gastritis. Pernicious anemia is one of several causes of vitamin B12 deficiency, and is treatable with vitamin B12 injections.

Vitamin B12 injections for the intrinsic factor-challenged

Most people don’t require vitamin B12 injections to avoid deficiency, for the simple reason that most people make enough intrinsic factor to absorb vitamin B12 from the foods they eat.

When you eat B12-rich foods like beef, chicken, fish, or cheese, your stomach manufactures a substance, intrinsic factor, that attaches itself to vitamin B12, escorts it through the digestive tract, and delivers it to the small intestine, where the vitamin B12 molecules enter the bloodstream.

But not everybody is able to produce intrinsic factor (or access it), and must instead receive their cobalamin through vitamin B12 injections, regardless of diet.

People who require vitamin B12 injections are:

  • Pernicious anemia patients
  • People who have undergone bariatric surgery, such as gastric bypass
  • People who have had gastrointestinal surgery to treat Crohn’s disease or ulcerative colitis
  • Diabetics who take metformin
  • GERD patients who take protein pump inhibitors (PPIs)
  • Sufferers of gastrointestinal problems such as with celiac disease, migraines, inflammatory bowel syndrome (IBS), cyclical vomiting, and fibromyalgia
  • Anybody who is susceptible to autoimmune disorders
  • Elderly individuals
  • Alcoholics
  • Sometimes, people with Helicobacter pylori (H. pylori)


Preparing yourself for vitamin B12 injections

If you’re squeamish about needles, then won’t like getting vitamin B12 injections, as they require insertion into the thickest, most muscular sections of your body, such as your thigh or buttock. Vitamin B12 injections contain cobalamin, a bright red liquid vitamin B12.

Because cobalamin is a thick liquid, the injection itself can be painful, and the pain can last for several hours. Sometimes, bruising and scarring result from vitamin B12 injections.

In some states, vitamin B12 injections are available without prescription. Some people opt to self-administer vitamin B12 injections, but that is not advised, as nerve damage can occur.

For people who are nervous about getting monthly vitamin B12 injections, there are other options in the form of over-the-counter (OTC) vitamin B12 supplements, which don’t require prescription.