The Truth About Vitamin B12 Injections

Vitamin B12 deficiency is common among vegans and vegetarians who often don't get enough B12 from their food, and it can pop up in other cases, too. "Vitamin B12 is an essential nutrient for human health," Elizabeth Ko, assistant clinical professor of medicine at UCLA's David Geffen School of Medicine, told InStyle. "It plays a key role in the function of the brain and nervous system, and it's crucial to red blood cell production in the bone marrow. [It] also aids in DNA synthesis and is involved in the metabolism of carbohydrates, fats, and proteins." 

Because it's so important, those with this type of vitamin deficiency, which is diagnosed via a blood test, are usually recommended to take either supplements or get regular B12 shots. "For those who have a mild or moderate deficiency, or for vegans, then oral B12 supplements generally suffice," Ko explained. "For those who have a severe deficiency, injections can quickly raise the level."

Shanna Levine, a primary care physician and instructor of medicine at the Mount Sinai Health System, believes injections are the best way to get B12 if you have a deficiency. "Injections are the preferred treatment for patients unable to absorb vitamin B12, such as patients with autoimmune-related anemia or pernicious anemia, or history of gastrectomy, which means partial removal of the stomach, or a history of bariatric surgery," Levine told InStyle. They are often self-administering, meaning you can inject yourself after undergoing training with your doctor, or have a close family member or friend do it if you can't stand the sight of needles.

However, vitamin B12 injections are not without their risks. "Patients should only use injections if indicated by their healthcare provider, as the benefits of the treatment should outweigh any risks," warned Levine, listing hypokalemia as a potential side effect, which means your potassium levels are too low. According to Healthline, like almost anything your ingest or inject in your body, when getting B12 shots, there is also a possibility that you may experience an allergic reaction or sensitivity. Most people, though, can tolerate them well, and enjoy increased B12 levels as a result.