Eggs with high vitamin B12 content against a blue background

Does B12 Help With Weight Loss?

Written on August 28, 2023 by Sendra Yang, PharmD, MBA. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

Vitamins are essential for your body to function correctly.[1] The known vitamins are A, C, D, E, K, and B.[2] There are eight B vitamins, one of which is vitamin B12. Vitamin B12, also known as cobalamin, is vital for various pathways in the body.[2,3] It is a water-soluble vitamin, meaning it cannot be stored in your fat tissues, and you need to consume this vitamin throughout your diet.[3]

With the increasing obesity prevalence (up to around 42%) in the United States and many people trying to lose weight every year, B12 has been suggested as a possible remedy for weight loss.[4-6] Continue reading to learn more about whether B12 can help with weight loss.

What Does Vitamin B12 Do?

Vitamin B12 has a role in proper red blood cell formation, cell metabolism, nerve function, and DNA production.[3,7] DNA is the genetic material located inside body cells. Vitamin B12 is needed for two significant enzymes central to biological pathways, including DNA and protein synthesis. Vitamin B12 also impacts the process of fat metabolism.[8]

Sources Of B12

Vitamin B12 is absorbed through the intestines and can be stored in the liver for up to a year.[9] B12 is available in foods like red meats, fish, poultry, eggs, milk, and dairy products.[14] The vitamin can also be fortified in foods such as nutritional yeast, certain bread, and breakfast cereals. Fortified foods are foods with added vitamins and nutrients that do not naturally have them.

Vitamin B12 And Obesity

Human trials have demonstrated the association of vitamin B12 with obesity.[9-11] A study including 9,075 adult participants in the National Health and Nutrition Examination Survey evaluated the association of serum vitamin B12 concentrations with obesity in the United States.[10] The serum vitamin B12 concentrations were found to be lower in obese adults compared with non-obese adults. Individuals with higher serum vitamin B12 levels were less likely to be obese. However, some studies investigating the association between vitamin B12 concentrations and obesity were inconsistent.[12, 13]

Does Vitamin B12 Help With Weight Loss?

Vitamin B12 has various functions in the different body pathways.[3,7,8] Although some studies have reported an association between low vitamin B12 levels and obesity, the results were inconsistent.[9-13] So, does vitamin B12 help with weight loss? It is not clear if vitamin B12 can lead to losing weight.[6] Vitamin B12 has been suggested to help increase energy levels in people with low levels. But if you already have normal vitamin B12 serum levels, supplementing with vitamin B12 will not likely improve your energy.[6,7]

Everlywell Weight Loss Support

Vitamin B12 Deficiency

Vitamin B12 deficiency occurs when you do not have enough or are not absorbing enough vitamin B12 for your body.[14] Not getting adequate amounts of vitamin B12 can cause physical, nerve, and mental issues. Conditions that can lead to vitamin B12 deficiency include [14]:

  • Insufficient vitamin B12 in your diet
  • Gastritis
  • Pernicious anemia (a rare medical condition where your stomach is not able to make a protein that your body needs to absorb vitamin B12)
  • Digestive diseases
  • Gastrointestinal surgery
  • Alcohol use disorder
  • Transcobalamin II deficiency (a rare genetic disorder impairing vitamin B12 transport)

Symptoms of vitamin B12 deficiency can develop slowly and worsen over time, though some people have no symptoms.[14] General physical symptoms are fatigue, nausea, vomiting, diarrhea, sore mouth or tongue, yellowish skin, diminished appetite, and weight loss. Nerve-related symptoms may not be reversible and include vision issues, numbness or tingling in your hands and feet, memory loss, confusion, and difficulty walking or speaking.

Next Steps With Everlywell

If you are trying to lose weight and would like to discuss it with a healthcare provider, Everlywell has a Weight Care+ program that pairs GLP-1 prescriptions online with regular clinical care, lab testing, and support for related conditions. You have access to regular one-on-one virtual visits with a licensed healthcare provider to discuss your weight goals with lifestyle support and recommendations.

During the initial session, your healthcare provider will review and evaluate your medical history and order any appropriate lab testing that may be needed to determine whether weight loss medication may be for you. At your second visit, your provider will evaluate your test results and discuss your health and weight-related goals to help design a personalized care plan. If you start a medication, you will have regular check-ins with your certified clinician. They will review your weight loss progress, assess your medication tolerance, order follow-up lab testing or prescription refills, and adjust your care plan as necessary.

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  1. Tardy AL, Pouteau E, Marquez D, Yilmaz C, Scholey A. Vitamins and minerals for energy, fatigue and cognition: A narrative review of the biochemical and clinical evidence. Nutrients. 2020;12(1):228. doi: 10.3390/nu12010228
  2. Vitamins and minerals. National Center for Complementary and Integrative Health. Accessed August 19, 2023.
  3. Vitamin B12. NIH Office of Dietary Supplements. Accessed August 19, 2023.
  4. Adult obesity facts. Centers for Disease Control and Prevention. May 17, 2022. Accessed August 19, 2023.
  5. Data briefs - number 313 - July 2018. Attempts to lose weight among adults in the US, 2013-2016. Centers for Disease Control and Prevention. July 12, 2018. Accessed August 14, 2023.
  6. B-12 shots: Do they work for weight loss? Mayo Clinic. September 13, 2022. Accessed August 19, 2023.
  7. Vitamin B-12. Mayo Clinic. August 10, 2023. Accessed August 19, 2023.
  8. Boachie J, Adaikalakoteswari A, Samavat J, Saravanan P. Low vitamin B12 and lipid metabolism: Evidence from pre-clinical and clinical studies. Nutrients. 2020;12(7):1925. doi: 10.3390/nu12071925
  9. Pei X, Yao J, Ran S, Lu H, Yang S, Zhang Y, Wang M, Shi H, Tan A. Association of serum water-soluble vitamin exposures with the risk of metabolic syndrome: results from NHANES 2003-2006. Front Endocrinol (Lausanne). 2023;14:1167317. doi: 10.3389/fendo.2023.1167317
  10. Sun Y, Sun M, Liu B, Du Y, Rong S, Xu G, Snetselaar LG, Bao W. Inverse association between serum vitamin B12 concentration and obesity among adults in the United States. Front Endocrinol (Lausanne). 2019;10:414. doi: 10.3389/fendo.2019.00414
  11. Ozer S, Sonmezgoz E, Demir O. Negative correlation among vitamin B12 levels, obesity severity and metabolic syndrome in obese children: A case control study. J Pak Med Assoc. 2017;67(11):1648-1653.
  12. Oliai Araghi S, Braun KVE, van der Velde N, van Dijk SC, van Schoor NM, Zillikens MC, de Groot LCPGM, Uitterlinden AG, Stricker BH, Voortman T, Kiefte-de Jong JC. B-vitamins and body composition: integrating observational and experimental evidence from the B-PROOF study. Eur J Nutr. 2020;59(3):1253-1262. doi: 10.1007/s00394-019-01985-8
  13. Allin KH, Friedrich N, Pietzner M, Grarup N, Thuesen BH, Linneberg A, Pisinger C, Hansen T, Pedersen O, Sandholt CH. Genetic determinants of serum vitamin B12 and their relation to body mass index. Eur J Epidemiol. 2017;32(2):125-134. doi: 10.1007/s10654-016-0215-x
  14. Vitamin B12 deficiency: Symptoms, causes & treatment. Cleveland Clinic. Accessed August 19, 2023.
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