The 8 Best B12 Supplements of 2023, According to a Dietitian

Nature Made's Sublingual B12 has 1,000 micrograms of B12 and is USP Verified

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Best B12 Supplements

VWH / Amazon / Thorne / Vitacost

Most people who eat a varied diet including animal foods like meat, fish, eggs, and poultry get enough B12 through food. However, anyone following a mostly plant-based diet or vegan diet may need a supplement to get enough. Additionally, registered dietitian Amanda Lane notes, “people over 60 or those that have any type of digestive disorder may not absorb B12 efficiently, and a supplement may be needed even if you do eat a diet that contains B12.” Supplements may also be helpful for people who have had GI or bariatric surgeries, or have certain medical conditions that can affect the body’s ability to metabolize and absorb B12.

The best way to know if you need a B12 supplement is to have your levels checked. “Your healthcare provider can check your B12 levels, but it is not part of routine blood work, so if you are concerned, ask for it specifically,” recommends Lane. Knowing your baseline will also help a healthcare professional determine the best form and dose for repleting your stores if you’re deficient. The two most common forms of B12 found in supplements are cyanocobalamin and methylcobalamin.

You can find B12 as an individual supplement, as part of a B-complex supplement alongside other B-vitamins, and in certain multivitamins, including prenatal vitamins. Because of this, it's helpful to check the B12 levels in other supplements you’re taking if you are thinking of adding a separate B12 supplement. To compile our list of top B12 supplements, our dietitian (who works with many plant-based eaters in her practice) consulted trusted experts in the field and carefully examined the different supplements on the market including ingredients, form, dose, company reputability, and third-party testing.

Editor's Note

Our team of registered dietitians reviews and evaluates every single supplement we recommend according to our dietary supplement methodology. From there, a registered dietitian on our Medical Expert Board reviews each article for scientific accuracy.

For those taking gastric acid inhibitors or metformin, a sublingual supplement or B12 injections may be more suitable. Also, if you have sensitivity to cobalt, a methylcobalamin B12 supplement may be better.

Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs, and to find out what dosage to take.

Best Overall

Nature Made Sublingual B-12 1,000 mcg

Nature's Made Sublingual B-12 1000 mcg


  • Form may be better absorbed

  • Budget-friendly

  • USP verified

  • Some people may not like the flavor

Nature’s Made Sublingual B-12 lozenges are an easy and effective way to prevent or treat deficiency whether you don't get enough through diet or have difficulty absorbing B12 from food. These cherry lozenges are absorbed in your mouth (under your tongue) and go directly into the bloodstream, bypassing the gut. This may be important for those who have lower levels of intrinsic factor—a protein required for B12 absorption in the small intestine—or have poor gut absorption rates due to medical conditions or medications. Sublingual B12 has been shown to be as effective at treating deficiency as intramuscular injections.

We like that Nature’s Made products are USP verified and are budget-friendly. For those that might benefit from a higher B12 dose, they also make a 2,000 microgram (mcg) and 3,000 microgram lozenge. Keep in mind you only absorb about 1.3 percent of the B12 in supplement doses this high, so the additional benefits of megadoses may not be significant.

Price at time of publication: $7 for 50 count ($0.14/ serving)

Form: Lozenge | Dose: 1,000mcg | Servings per container: 50

Best B-complex

Designs for Health B-Supreme

Designs for Health B-Supreme


  • NSF certified

  • Contains active form of B12

  • Vegan, allergy-friendly

  • Lower dose of vitamin B12

“When there are multiple B vitamin deficiencies I typically recommend seeking out a B complex,” says registered dietitian Jenna Volpe. The Designs for Health B-Supreme is a quality supplement that is NSF certified, a third-party agency that tests for purity and accuracy of the label. It contains methylcobalamin, an active form of B12 that may be better absorbed by the body than cyanocobalamin (though more research is needed).

This B-complex vitamin supplement contains a lower dose of B12 than some singular supplements at 250 micrograms per serving. This may be adequate for many people as a maintenance dose, but might be low for those that are deficient and require repletion. Ask a healthcare provider to determine the best dose for you and if a B complex is the right choice for your needs.

Designs for Health B-Supreme is vegan, gluten-free, soy-free, dairy-free, and Non-GMO making it a good choice for those with these dietary restrictions.

Price at time of publication: $24 for 60 count ($0.40/ serving)

Form: Capsule | Dose: 250mcg | Servings per container: 60 

Best Spray

Garden of Life mykind Organic Whole Food B-12 for Metabolism and Energy, Raspberry

Garden of Life B12 Vitamin - mykind Organic Whole Food B-12 for Metabolism and Energy, Raspberry


  • approved

  • Suitable for those with impaired gastrointestinal absorption

  • Active from of B12

  • Requires refrigeration

Those with impaired gastrointestinal absorption, including bariatric patients, may benefit from a sublingual or spray form of B12, to allow for absorption in the mouth. We like Garden of Life myKind Organic Whole Food B12, containing 500 micrograms of the active form of B12, methylcobalamin, from a certified organic food blend of fruits and vegetables.

This spray is flavored with organic fruit juices and citrus extracts, and sweetened with stevia. It rates high from consumers on both taste and ease of use. Note that this product is not intended for children and does require refrigeration after opening.

This product is USDA Organic, Certified Vegan and Gluten-Free, and has been tested and approved through's voluntary certification program, and was included in's 2023 B Vitamins Supplements Review.

Price at time of publication: $16 for 140 sprays ($0.11/ spray)

Form: Spray | Dose: 500 micrograms (1 spray) | Servings per container: 140 

Best Liquid

Vitacost Liquid Vitamin B12

Vitacost Liquid Vitamin B12


  • Third-party tested

  • Adjustable dose

  • Vegan and gluten-free

  • Not suitable for someone with a soy allergy

Vitacosts’s Liquid Vitamin B12 is a good choice for someone who struggles with other forms of supplements like tablets and capsules. The liquid form also allows you to adapt the right dose for you by adding more or less than the suggested serving size of 16 drops, which contains 1,000 micrograms of cyanocobalamin. You can place the drops directly on your tongue or add them to a glass of water, juice, or a smoothie.

This supplement is third-party tested and approved for purity and potency, and is also vegan, and gluten-free. However, it does contain soy, so it is not appropriate for someone with a soy allergy.

Price at time of publication: $7 for 74 servings ($0.09/ serving)

Form: Liquid | Dose: 1,000mcg | Servings per container: 74 

Best Lozenge

NOW Foods Methyl B-12 1,000mcg Lozenges

NOW Foods Methyl B-12 1,000mcg Lozenges


  • Contains active form of B12

  • Allergy-friendly 

  • Vegan, Kosher, and Halal

  • Must be chewed or dissolved under tongue

Lozenges may be the preferred form for those that have difficulty absorbing B12 such as older adults with lower intrinsic factor, people who have had bariatric surgery, and those that have medical conditions that affect their small intestine. Now Foods Methyl B-12 is a budget-friendly, quality option that meets nearly every dietary need or preference. It’s free of the top 8 allergens and is vegan, kosher and halal. We also like this lozenge is the active form of B12, methylcobalamin, that may be better absorbed by some people.

People who have trouble swallowing tablets or capsules will welcome this easy-to-consume lozenge. However, it does have to be chewed or dissolved under the tongue, which some people may not like. While it is not third-party verified by one of our preferred agencies, Now Foods does extensive in-house testing of all of their supplements for safety and quality.

Price at time of publication: $13 for 100 lozenges ($0.13/ serving)

Form: Lozenge | Dose: 1,000mcg | Servings per container: 100

Best Gummy

Country Life B12 Gummies

Country Life B12 Gummies


  • Certified vegan

  • No artificial flavors or colors

  • Certified gluten free

  • Contains added sugar

  • No third party testing

If you prefer a gummy vitamin, we recommend Country Life B12 Gummies.  Many gummy vitamins on the market are made with gelatin, which is not vegan. Country Life’s gummies are made with pectin and are certified vegan by the American Vegetarian Association. This is important since following a vegan or vegetarian diet increases your risk for B12 deficiency. While Country Life supplements are made in an NSF registered facility, their products are not third-party tested for ingredient amounts or contaminates.

While these gummies do contain added sugar, it’s very little—only 2 grams per gummy. We also like there are no artificial colors or flavors, soy, and gluten free making it a good option for those with these dietary needs. With 850 micrograms of B12 (as cyanocobalamin) per gummy, some people may need to take two gummies for adequate repletion if recommended from a healthcare professional.

Price at time of publication: $21 for 120 count ($0.17 per serving)

Form: Gummy | Dose: 850mcg | Servings per container: 60 

Best Multivitamin with B12

Thorne Research Basic Nutrients 2/Day

Thorne Research Basic Nutrients 2/Day


  • NSF Certified for Sport

  • Active form of B12

  • High dose of B12

  • Contains other nutrients that may interact with certain medications

If you have multiple nutrient deficiencies or have higher nutrient needs, a multivitamin can be an easy and cost-effective way to meet your needs. Thorne Basic Nutrients 2/Day contains 600 micrograms of methylcobalamin, making it a good choice for those that need to treat or prevent a B12 deficiency since many multivitamins only contain a small amount of B12 (2.5 to 15 micrograms), and some don’t contain any.

Thorne is known for its high quality supplements and is NSF Certified for Sport, which means that it’s free of unsafe levels of contaminants and substances banned for athletes. It’s also dairy-free, soy-free, gluten-free, and vegan.

If you choose to take a multivitamin, know that some nutrients may interact with certain medications, so always check with a healthcare provider before starting a new supplement.

Price at time of publication: $34 for 60 count ($1.14/ serving)

Form: Capsule | Dose: 600mcg for 2 capsules | Servings per container: 30 

Best Low-Dose

Mason Natural Vitamin B12 50 mcg

Mason Natural Vitamin B12 50 mcg


  • Third-party tested

  • Allergy-friendly and Vegan

  • No artificial flavors

  • Tablet

If you need a lower dose maintenance level of vitamin B12, Mason Natural Vitamin B12 50mcg is a good choice. It’s third-party tested for purity and potency and is vegan, and free from the top 8 allergens.

The one drawback to this product is that it is in tablet form, which may not be absorbed as well by someone who has low levels of intrinsic factor or has reduced ability to absorb nutrients in the small intestine. It’s also not an adequate dose for those who have had bariatric surgery.

Of note, it contains a small amount of calcium, which is considered safe for most people. However, calcium supplements can interact with iron absorption as well as some antibiotics, so the supplement should be taken separately from certain medications or other supplements.

Price at time of publication: $7 for 100 count ($0.07/ tablet)

Form: Tablet | Dose: 50mcg | Servings per container: 100 

Are B12 Supplements Beneficial?

B12 supplements are helpful in treating and preventing those with a deficiency. The following groups of people are at risk for deficiency, and may benefit from a supplement. 

  • Vegans and Vegetarians. “Many vegans and vegetarian eaters don’t take in enough vitamin B12. This is because many sources are animal based, and the nutrient isn’t always easy to get enough of on a plant-based diet,” says plant-based dietitian Amy Gorin.
  • Older Adults. People over the age of 65 may have lower levels of stomach acid, which is required to break down and absorb B12. If there is not enough stomach acid, the B12 cannot combine with intrinsic factor in the stomach, and this step is needed to absorb B12 in the small intestine.
  • People with certain digestive disorders or illnesses. People with digestive disorders affecting the stomach and small intestine such as Crohn’s, small intestinal bacterial overgrowth (SIBO), H.Pylori, and Celiac disease may not be able to properly absorb B12.
  •  People who have had bariatric surgery. Bariatric surgeries such as the roux-en-y gastric bypass put patients at risk for B12 (among other nutrient) deficiency. This is related to lower intrinsic factor production, lower stomach acid, and bypassing a part of the small intestine called the duodenum, which is the main site of B12 absorption.
  • People taking certain medications. Some medications, especially those aimed to treat gastroesophageal reflux disease (GERD), reduce stomach acid content which can increase risk for B12 deficiency. Metformin, a common diabetes medication, is also associated with B12 deficiency. 
  • People who have a variant of the MTHFR gene: “People who have a variant of the MTHFR gene mutation might need to take B12, since this gene mutation interferes with the body's natural ability to use certain B vitamins including B12,” says Jenna Volpe.
  • People with HIV. Studies suggest that up to 10 percent of people with HIV are deficient in B12. If you have HIV, have your B12 levels checked and discuss with a healthcare professional to see if you could benefit from a supplement.

Who May Not Benefit from a B12 Supplement

In general, B12 supplements are safe for most people. Vitamin B12 is water soluble, which means that your body will excrete what it doesn’t need through urine. However, many people don’t need a B12 supplement and consuming excess B12 does not provide any additional benefits.

The following types of people may not benefit from taking a B12 supplement:

  • People that regularly eat animal protein. The best food sources of B12 include meat, fish, poultry, eggs, and milk. If you regularly consume these foods, you should be getting enough through your diet.
  • People taking certain medications. Both gastric acid inhibitors (medications to treat GERD) and Metformin (used to treat diabetes) may reduce the body’s ability to absorb vitamin B12, including from certain supplements. If you take these medications and are deficient in B12, you may need to consider a sublingual supplement or talk to a healthcare provider about B12 injections.
  • People with a sensitivity to cobalt. Cobalt is present in cyanocobalamin, the most common form of B12 supplements. If you have a known cobalt allergy, it’s recommended you take a different form of B12 like methylcobalamin.

How We Select Supplements

Our team works hard to be transparent about why we recommend certain supplements; you can read more about our dietary supplement methodology here

We support supplements that are evidence-based and rooted in science. We value certain product attributes that we find to be associated with the highest quality products. We prioritize products that are third-party tested and certified by one of three independent, third-party certifiers: USP, NSF, or 

It's important to note that the FDA does not review dietary supplements for safety and effectiveness before they go to market. Our team of experts has created a detailed, science-backed methodology to choose the supplements we recommend. We also consulted with the following registered dietitians:

  • Amanda Lane, MS, RDN, CDCES, dietitian specializing in dialysis at Plant-Powered Kidneys Renal Nutrition Services
  • Jenna Volpe, RDN, LD, CLT, functional dietitian and founder of Whole-istic Living
  • Amy Gorin, MS, RDN, inclusive plant-based dietitian and owner of Plant Based with Amy

What to Look For

Third-Party Testing 

Supplements that are third-party tested are sent to a lab where they are tested to ensure they contain what they say they contain and are not contaminated with specific high-risk, common contaminants. However, it’s important to note:

  • Third party testing does not test to see if a product is effective or safe for everyone, and it does not ensure the supplement will not interact with other supplements or medications.
  • Not all third-party testing is created equal. It is not uncommon for supplement companies to pay labs for certificates after conducting minimal to no testing. 
  • The third party certifications we can trust are:, NSF, and USP. However, these certifications are difficult to obtain and/or expensive for manufacturers, so many companies choose not to get their products tested by one of these three organizations. 
  • Sometimes products tested by these three companies are more expensive to try to offset the cost they pay for certification.
  • Just because a supplement is not tested by one of these three companies, it does not mean it’s a bad product. We recommend doing some research on the reputability of the manufacturer, and calling up the manufacturer and their testing lab to determine their protocols and decide if you feel comfortable consuming the supplement.


There are four different forms of vitamin B12: cyanocobalamin, methylcobalamin, adenosylcobalamin, and hydroxocobalamin. Methylcobalamin and adenosylcobalamin are active forms of vitamin B12 whereas the others require the body to convert it to the active form.  According to the National Institutes for Health, there is no evidence to suggest that absorption rates vary significantly between forms. Recent research comparing the two most common forms (methylcobalamin and cyanocobalamin) is limited.

Vitamin B12 supplements are available in capsule, sublingual, chewable, liquid, spray and injection (a high dose requiring a prescription from a healthcare provider). The best form for you will depend on the reason for deficiency.

“People who are dealing with low B12 levels due to poor stomach acid absorption may benefit most from a B12 shot or sublingual version of a B12 supplement, since these delivery methods bypass the gut,” says Volpe. She adds, “You'll start absorbing it in your mouth instead of waiting for it to be activated by your stomach acid and released through your small intestine—which may not be working effectively."

Vitamin B12 is also found in combination with other B-vitamins as well as in multivitamins and prenatal vitamins. “When there are multiple B vitamin deficiencies or other vitamin or mineral deficiencies uncovered, I typically recommend seeking out a B complex or multivitamin or prenatal containing methylated B12 versus just taking a B12 supplement,” says Volpe.

Ingredients & Potential Interactions

It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included, relative to the recommended daily value of that ingredient. Please bring the supplement label to a healthcare provider to review the different ingredients contained in the supplement and any potential interactions between these ingredients and other supplements and medications you are taking.

If you’re taking vitamin B12 as part of a B-complex or multivitamin, always check with your healthcare provider to ensure the other ingredients are safe for you as they may contain ingredients that can interact with medications or other supplements you take.

Vitamin B12 Dosage 

Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs and to understand which dosage to take. 

The Recommended Daily Allowance for adults for vitamin B12 is 2.4 micrograms. Pregnant and lactating people need 2.6 micrograms and 2.8 micrograms respectively. Most supplements come in much higher doses because the body can’t absorb everything consumed through supplements. The recommended dose for those with deficiency is 1,000 to 2,000 micrograms, especially to correct anemia or neurological symptoms. It’s also recommended that people who have had bariatric surgery take 1,000 micrograms daily.

It’s estimated that absorption rates for those containing less than 2 micrograms of vitamin B12 is about 50 percent. That significantly decreases with higher doses. Supplements with 500 micrograms of vitamin B12 are absorbed at about a 2 percent rate and 1,000 - 2,000 micrograms are absorbed at only 1.3 percent. That means if you take a supplement that contains 2,000 micrograms of vitamin B12, you’re likely absorbing about 26 micrograms. 

How Much is Too Much? 

There is currently no established tolerable upper limit (UL) for vitamin B12 as there is low risk of toxicity. Because it’s a water soluble vitamin, your body excretes what it doesn’t need in urine.

Frequently Asked Questions

  • How long does it take for B12 supplements to work?

    The exact amount of time will likely depend on your status—mild deficiencies and symptoms will resolve more quickly than more significant deficiencies. “Some people notice a difference in how they feel within a few days after starting B12 supplements, but it can take up to 2 weeks to effectively change your B12 levels,” says Lane.

  • Can B12 supplements raise blood pressure?

    The relationship between vitamin B12 and blood pressure is still being explored. One older study among rats suggests that vitamin B12 may actually lower blood pressure. Results from human studies are inconsistent. One study found that dietary intake of some B-vitamins was linked to lower blood pressure, though there appeared to be no correlation between vitamin B12 and blood pressure. Another study that looked at blood levels of B12, folate, and homocysteine found that higher levels of both homocysteine and B12 was associated with hypertension (high blood pressure) among women, but not men.

    However, red meat intake — which is a source of B12— is also linked to higher levels of homocysteine and higher blood pressure. There’s also thought that vitamin B12 and other B vitamins may lower homocysteine levels, which could support overall heart health. To date, there haven’t been any studies suggesting B12 supplements raise blood pressure.

    Yes, it is safe to take a vitamin B12 supplement daily. Because your body can only absorb a small percentage of the dose from supplements. If you’re taking B12 supplements because you are deficient or don’t consume enough through diet, it’s recommended you take it daily.

  • What is the supplement B12 good for?

    If you’re not getting enough through diet or have lower absorption due to age or a medical condition, supplements are helpful in treating or preventing a deficiency. Sometimes B vitamins can be marketed as a way to increase energy. However, if you are not deficient in B12, there is no evidence that taking B12 supplement will increase energy levels.

  • What are the symptoms of B12 deficiency?

    Signs and symptoms of B12 deficiency can include anemia, fatigue, weakness, loss of appetite, pale skin, and dementia. You might also experience neurological symptoms such as numbness or tingling of hands and feet. Low B12 has also been associated with depression, and supplements can be an effective treatment when there is a deficiency. If you think you are experiencing any of these symptoms, speak with a healthcare professional to confirm a deficiency and before taking any supplements.

  • What is the average cost of B12?

    B12 supplements can range in price from less than $0.10 to over $1 per recommended daily serving. The cost will be impacted by the serving size, level and form of B12, and manufacturing costs such as third party certifications from some companies. Our best overall pick is at the lower end of price at $0.14 per recommended serving and is third party certified.

22 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institutes of Health Office of Dietary Supplements. Vitamin B12.

  2. NIH National Library of Medicine. Intrinsic Factor.

  3. Bensky, M. J., Ayalon-Dangur, I., Ayalon-Dangur, R., Naamany, E., Gafter-Gvili, A., Koren, G., & Shiber, S. (2019). Comparison of sublingual vs. intramuscular administration of vitamin B12 for the treatment of patients with vitamin B12 deficiency. Drug delivery and translational research, 9(3), 625–630.

  4. NSF International. What is NSF Certification?

  5. Gupta JK* and Qureshi Shaiba Sana. (2015) Potential Benefits of Methylcobalamin: A Review. Austin J Pharmacol Ther. 3(3).1076.

  6. Cooperman T, M.D. Vitamin b supplement reviews & top picks.

  7. NSF International unveils New Contents Certified and Certified for Sport® Certification Marks: Certified for Sport®. NSF International Certified for Sport.

  8. Langan, R. C., & Goodbred, A. J. (2017). Vitamin B12 Deficiency: Recognition and Management. American family physician, 96(6), 384–389.

  9. National Library of Medicine. Calcium.

  10. Rizzo, G., Laganà, A. S., Rapisarda, A. M., La Ferrera, G. M., Buscema, M., Rossetti, P., Nigro, A., Muscia, V., Valenti, G., Sapia, F., Sarpietro, G., Zigarelli, M., & Vitale, S. G. (2016). Vitamin B12 among Vegetarians: Status, Assessment and Supplementation. Nutrients, 8(12), 767.

  11. Harvard School of Public Health. Vitamin B12.

  12. Lupoli, R., Lembo, E., Saldalamacchia, G., Avola, C. K., Angrisani, L., & Capaldo, B. (2017). Bariatric surgery and long-term nutritional issues. World journal of diabetes, 8(11), 464–474.

  13. Heidelbaugh J. J. (2013). Proton pump inhibitors and risk of vitamin and mineral deficiency: evidence and clinical implications. Therapeutic advances in drug safety, 4(3), 125–133.

  14. Al-Batayneh, K. M., Zoubi, M., Shehab, M., Al-Trad, B., Bodoor, K., Khateeb, W. A., Aljabali, A., Hamad, M. A., & Eaton, G. (2018). Association between MTHFR 677C>T Polymorphism and Vitamin B12 Deficiency: A Case-control Study. Journal of medical biochemistry, 37(2), 141–147.

  15. Adhikari, P. M., Chowta, M. N., Ramapuram, J. T., Rao, S., Udupa, K., & Acharya, S. D. (2016). Prevalence of Vitamin B12 and folic acid deficiency in HIV-positive patients and its association with neuropsychiatric symptoms and immunological response. Indian journal of sexually transmitted diseases and AIDS, 37(2), 178–184.

  16. NIH National Library of Medicine. Cyanocobalamin.

  17. França, C. F., & Vianna, L. M. (2010). Effectiveness of B vitamins on the control of hypertension and stroke events of SHRSP rats. Journal of dietary supplements, 7(1), 71–77.

  18. Liu, R., Mi, B., Zhao, Y., Li, Q., Yan, H., & Dang, S. (2017). Effect of B Vitamins from Diet on Hypertension. Archives of medical research, 48(2), 187–194.

  19. Tamura, T., Kuriyama, N., Koyama, T., Ozaki, E., Matsui, D., Kadomatsu, Y., Tsukamoto, M., Kubo, Y., Okada, R., Hishida, A., Sasakabe, T., Kawai, S., Naito, M., Takashima, N., Kadota, A., Tanaka, K., Hara, M., Suzuki, S., Nakagawa-Senda, H., Takezaki, T., … Wakai, K. (2020). Association between plasma levels of homocysteine, folate, and vitamin B12, and dietary folate intake and hypertension in a cross-sectional study. Scientific reports, 10(1), 18499.

  20. Diarz, E. J., Leyaro, B. J., Kivuyo, S. L., Ngowi, B. J., Msuya, S. E., Mfinanga, S. G., Bonfoh, B., & Mahande, M. J. (2020). Red meat consumption and its association with hypertension and hyperlipidaemia among adult Maasai pastoralists of Ngorongoro Conservation Area, Tanzania. PloS one, 15(6), e0233777.

  21. Debreceni, B., & Debreceni, L. (2014). The role of homocysteine-lowering B-vitamins in the primary prevention of cardiovascular disease. Cardiovascular therapeutics, 32(3), 130–138.

  22. ​​Sangle, P., Sandhu, O., Aftab, Z., Anthony, A. T., & Khan, S. (2020). Vitamin B12 Supplementation: Preventing Onset and Improving Prognosis of Depression. Cureus, 12(10), e11169.