Can vitamin B12 injections boost your health?

Although medical professionals have long used shots to correct severe nutrient deficiencies quickly, you can now book a vitamin shot as a spa treatment add-on.

One common offering is a B12 shot, an injection containing a high dose of (you guessed it) vitamin B12, also known as cobalamin. 

Aside from correcting nutritional deficiencies, wellness spas offering injections boast a long list of health benefits, from increased energy to weight loss. But do these supplements actually help? What about people who get enough B12: will an injection give them a boost? Here’s what you need to know before getting a shot of B12.

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If you’re suffering from a deficiency, B12 injections are an effective way to get your levels back to normal. Healthcare professionals use shots that are injected into the muscle to treat low levels of B12.

While effective at correcting a cobalamin deficiency, B12 injections may not be the best treatment choice for you. Taking oral B12 via tablets or gummies is just as effective at getting a shot––and it’s also cheaper, one meta-analysis found (Wang, 2018). 

The main benefit of a B12 shot compared with other supplement routes is speed. This treatment works faster than oral B12 because it skips the process of digestion. While it may take oral B12 longer to raise low levels back to normal, the final results for each type of supplement are similar (Amin, 2021; Wang, 2018).

The downside of oral B12 is that it requires a substance in your gut called intrinsic factor in order to be absorbed. Some people don’t make enough intrinsic factor to keep their B12 levels high enough. In this case, an injection may be necessary (Amin, 2021).

Getting a vitamin B12 injection may also be painful, especially for thinner people. Unlike shots given just under the skin (subcutaneous injections), vitamin B12 shots have to go deeper to penetrate the muscle.

Injections are more likely to cause an allergic reaction than oral forms of B12, although allergic reactions to cobalamin shots are still very rare (Amin, 2021).

If you have a B12 deficiency, it’s vital that you fix it right away. How you do it matters less. 

Vitamin B12 is water-soluble and performs many essential functions in your body, such as keeping blood and nerve cells healthy. It also plays an important role in making DNA––another reason why a deficiency can have such serious impacts on your body.

The main symptom of a vitamin B12 deficiency is weakness or fatigue. Those with low levels can also experience other side effects including (NIH, 2021):  

• Heart palpitations (being aware of your heart beat) 

• Loss of appetite

• Pale skin, confusion

• Poor memory

• Balance issues

• Depression

• Weight loss

Eventually, not having enough of this vitamin can damage nerves, causing numbness or tingling in the hands or feet. A B12 deficiency can also affect your ability to get pregnant.

Does B12 help with weight loss?

Since a B12 deficiency causes fatigue and weakness, it may make exercising feel impossible. A lack of physical activity could then contribute to weight gain. 

In this case, boosting B12 levels may regulate weight due to increased energy levels and movement, although this hasn’t been studied. There are also no studies to date evaluating whether people with normal levels of B12 can benefit from supplementation when it comes to losing weight. 

Before seeking out dietary supplements, talk to a healthcare professional about whether you actually need one. If you eat a balanced, omnivorous diet, you’re likely getting enough B12 already.

If your blood levels are low, shots and oral supplements aren’t the only ways to raise them. Vitamin B12 is in many animal products like red meat, fish, poultry, eggs, and dairy products. This is why deficiencies are more common among vegans and vegetarians. Try incorporating these dietary sources into your weekly menu before turning to a supplement (Ankar, 2021).

If you follow a vegan diet and don’t eat any animal sources of B12, you’re not out of luck. There are various vitamin B12 supplements on the market, as well as fortified foods that don't contain animal products, such as nutritional yeast and breakfast cereals.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

August 10, 2021

Written by

Linnea Zielinski

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.