Are vitamin B-12 injections helpful for weight loss?

Answer From Brent A. Bauer, M.D.

There's no solid evidence that vitamin B-12 injections aid weight loss.

Vitamin B-12 is a water-soluble B complex vitamin found naturally in a variety of foods, including meat, fish and dairy products. Vitamin B-12 is also added to some foods and is available as a dietary supplement. Vitamin B-12 injections are commonly prescribed to help prevent or treat pernicious anemia and B-12 deficiency.

Some weight-loss clinics offer vitamin B-12 injections as part of their weight-loss programs. Proponents of vitamin B-12 injections say the shots give you more energy and boost your metabolism, helping you shed unwanted pounds. But unless you have a vitamin B-12 deficiency, vitamin B-12 injections aren't likely to give you an energy boost.

Metformin (Fortamet, Glucophage, Riomet) is a drug sometimes used as part of a weight-loss strategy for people with type 2 diabetes. Vitamin B-12 deficiency can be a side effect of this drug. If you take metformin, talk to your doctor about strategies to maintain adequate B-12 levels.

Getting large amounts of vitamin B-12 through vitamin B-12 injections isn't likely to harm your health. But vitamin B-12 can interfere with the effectiveness of some medications, so if you receive vitamin B-12 injections, be sure to let your doctor know.

If you're hoping to lose weight, resist the lure of quick and easy solutions. What counts is a healthy lifestyle. Enjoy healthier foods in appropriate quantities and include physical activity in your daily routine.

Get the latest health information from Mayo Clinic’s experts.

Sign up for free, and stay up to date on research advancements, health tips and current health topics, like COVID-19, plus expertise on managing health.

To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.

Aug. 26, 2020 See more Expert Answers