Vitamin B12
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Top-Rated Vitamin B12 Products
Evidence Summary
Vitamin B12 is an essential micronutrient involved in DNA synthesis, methylation, and neurological health. Research highlights its critical role in treating B12 deficiency, supporting maternal and fetal development, and its potential associations with cognitive function and metabolic health.
Evidence by Condition
Various administration routes including oral, intramuscular, and sublingual are evaluated for efficacy in treating deficiency (PMID: 29543316, 38231320).
B12 levels and homocysteine are associated with cognitive function in Parkinson's disease and impacts on fatigue and depressive symptoms (PMID: 33809274, 27840145).
B12 plays a role in neural tube development and maternal/child health outcomes, though research is ongoing regarding its role relative to folate (PMID: 38189492, 40573151).
Associations exist between B12 levels and the risk of coronary heart disease, metabolic syndrome, and intracranial aneurysms (PMID: 30431328, 37772082, 40147066).
Research investigates B12 as a modifiable nutritional biomarker in ASD, but evidence is still emerging (PMID: 40362647).
Effective Doses
Specific dose ranges were not explicitly provided in the provided research summaries.
Key Findings
- Comparison of oral, intramuscular, and sublingual routes for the treatment of B12 deficiency (PMID: 38231320)
- Association between plasma homocysteine, B12, and folate levels with cognitive function in Parkinson's disease (PMID: 27840145)
- The impact of B12 and folate supplementation on routine haematological parameters in older populations (PMID: 29520083)
- The emerging role of maternal Vitamin B12 in neural tube development (PMID: 40573151)
Limitations
The impact of B12 supplementation on homocysteine levels remains ambiguous when B12 levels are not already deficient (PMID: 37495210). Additionally, the specific role of B12 in neural tube development compared to folate is not yet fully established (PMID: 40573151).
Safety & Interactions
No specific contraindications or drug interactions were detailed in the provided research summaries.
AI-generated summary from 237 peer-reviewed studies. Not medical advice. Always consult a healthcare provider.
Dietary Reference Intakes
Source: IOM/NAM Dietary Reference Intakes · Dietary Reference Intakes: Vitamin B12 (cobalamin)
Drug-Supplement Interactions
⚠️ This information is for educational purposes only and does not constitute medical advice. Always consult your healthcare provider before combining supplements with medications.
Claims vs. Evidence
| Claim Type | % of Products | Evidence Required | Status |
|---|---|---|---|
| All Other | 99% | Tier D (Unclassified) | ✅ Supported |
| Structure/Function | 89% | Tier C (DSHEA Structure/Function (no pre-approval)) | ✅ Supported |
| Nutrient | 56% | Tier D (Unknown) | ✅ Supported |
| Approved Health | 1% | Tier A (FDA Approved Health Claim (21 CFR 101.9)) | ✅ Supported |
| No Claim | 0% | Tier D (No claim on label) | ✅ Supported |
| Qualified Health | 0% | Tier B (FDA Qualified Health Claim) | ✅ Supported |
🏛️ NIH ODS Factsheet
Research by Topic
⚠️ FDA Safety Data
Research Evidence (237)
**Tavares et al., 2025** | J Clin Neurosci | Meta Analysis Tavares Rodrigues Luiz Phelipe, Medeiros de Souza Gabriel da Costa, ... Figueiredo Eberval Gadelha. Associations between serum Homocysteine, vitamin B9, and vitamin B12 levels and the formati...
**Jayedi et al., 2019** | Crit Rev Food Sci Nutr | Meta Analysis Jayedi Ahmad, Zargar Mahdieh Sadat. Intake of vitamin B6, folate, and vitamin B12 and risk of coronary heart disease: a systematic review and dose-response meta-analysis of prospective ...
BACKGROUND: Vitamin B12 deficiency is common, and the incidence increases with age. Most people with vitamin B12 deficiency are treated in primary care with intramuscular (IM) vitamin B12. Doctors may not be prescribing oral vitamin B12 formulations ...
Vitamin B12 is often used to improve cognitive function, depressive symptoms, and fatigue. In most cases, such complaints are not associated with overt vitamin B12 deficiency or advanced neurological disorders and the effectiveness of vitamin B12 sup...
BACKGROUND: This systematic review and network meta-analysis aimed to evaluate the three different administration routes of vitamin B12: oral, intramuscular (IM), and sublingual (SL) routes. METHODS: We searched four electronic databases (PubMed, Sco...
**Afsar et al., 2020** | BMJ Open Gastroenterol | Meta Analysis Afsar Md Nure Alam, Jhinu Zannatun Nahar, ... Siddiqua Towfida Jahan. Helicobacter pylori infection and micronutrient deficiency in pregnant women: a systematic review and meta-analysis....
BACKGROUND: Vitamin B12 deficiency is a major public health problem worldwide, with the highest burden in elderly people, pregnant women, and young children. Due to its role in DNA synthesis and methylation, folate metabolism, and erythropoiesis, vit...
CONTEXT: Although some research suggests that vitamin B12 (hereafter, B12) supplements can lower homocysteine (Hcy) levels and treat hyperhomocysteinemia, these results are still ambiguous when B12 is taken as an isolated supplement. OBJECTIVE: This ...
**Dos et al., 2024** | Clin Nutr ESPEN | Systematic Review Dos Santos Maria Eduarda Rodrigues Alves, da Silva Karollainy Gomes, ... Barros Waleska Maria Almeida. Relationship between vitamin B12 levels and motor development: A systematic review. Clin...
BACKGROUND & AIMS: Metabolic syndrome (MetS) is associated with life-threatening conditions. Several studies have reported an association of vitamin B12, folic acid, or homocysteine (Hcy) levels with MetS. This systematic review and meta-analysis ass...
**Avram et al., 2025** | Int J Mol Sci | Meta Analysis Avram Oana-Elisabeta, Bratu Elena-Alexandra, ... Drima Eduard. Modifiable Nutritional Biomarkers in Autism Spectrum Disorder: A Systematic Review and Meta-Analysis of Vitamin D, B12, and Homocyst...
Hyperhomocysteinemia has been associated with cognitive disorders such as mild cognitive impairment, Alzheimer's disease and vascular dementia. Previous studies showed that levodopa-treated Parkinson's disease (PD) patients were likely to have elevat...
**Calderon-Ospina et al., 2020** | Pain Med | Meta Analysis Calderon-Ospina Carlos-Alberto, Nava-Mesa Mauricio Orlando, Arbeláez Ariza Carlos Emilio. Effect of Combined Diclofenac and B Vitamins (Thiamine, Pyridoxine, and Cyanocobalamin) for Low Back...
Background/Objectives: Folic acid (FA) supplementation can effectively reduce the occurrence of neural tube defects (NTDs). Vitamin B12 is involved in folate metabolism; however, studies have not reached a definitive conclusion on the association bet...
**Smelt et al., 2018** | Eur J Clin Nutr | Meta Analysis Smelt Antonia Fh, Gussekloo Jacobijn, ... Den Elzen Wendy Pj. The effect of vitamin B12 and folic acid supplementation on routine haematological parameters in older people: an individual partic...
**Choi et al., 2018** | Cochrane Database Syst Rev | Meta Analysis Choi Gwang-Ho, Wieland L Susan, ... Shin Byung-Cheul. Acupuncture and related interventions for the treatment of symptoms associated with carpal tunnel syndrome. Cochrane Database Sys...
**He et al., 2022** | Nutr Cancer | Meta Analysis He Jianbo, Fu Hongjuan, ... Chang Hui. Association between Vitamin B12 and Risk of Gastric Cancer: A Systematic Review and Meta-Analysis of Epidemiological Studies. Nutr Cancer. 2022;74(9):3263-3273. ...
BACKGROUND: Vitamin B12 deficiency is common and rises with age. Most people with vitamin B12 deficiency are treated in primary care with intramuscular vitamin B12 which is a considerable source of work for health care professionals. Several case con...
**Alfred et al., 2013** | J Nutr | Meta Analysis Alfred Tamuno, Ben-Shlomo Yoav, ... Day Ian N M. Genetic variants influencing biomarkers of nutrition are not associated with cognitive capability in middle-aged and older adults. J Nutr. 2013-May;143(...
**Grarup et al., 2013** | PLoS Genet | Meta Analysis Grarup Niels, Sulem Patrick, ... Pedersen Oluf. Genetic architecture of vitamin B12 and folate levels uncovered applying deeply sequenced large datasets. PLoS Genet. 2013-Jun;9(6):e1003530. doi:10....
**Lamjadli et al., 2025** | Int J Immunopathol Pharmacol | Meta Analysis Lamjadli Saad, Oujamaa Ider, ... Admou Brahim. Micronutrient deficiencies in patients with celiac disease: A systematic review and meta-analysis. Int J Immunopathol Pharmacol. 2...
**Bakaloudi et al., 2021** | Clin Nutr | Systematic Review Bakaloudi Dimitra Rafailia, Halloran Afton, ... Chourdakis Michail. Intake and adequacy of the vegan diet. A systematic review of the evidence. Clin Nutr. 2021-May;40(5):3503-3521. doi:10.101...
**Wiedemann et al., 2022** | Cell Rep Med | Meta Analysis Wiedemann Arnaud, Oussalah Abderrahim, ... Guéant Jean-Louis. Clinical, phenotypic and genetic landscape of case reports with genetically proven inherited disorders of vitamin B12 metabolism: ...
**Hipp et al., 2023** | Surgery | Meta Analysis Hipp Julian, Hillebrecht Hans Christian, ... Diener Markus K. Systematic review and meta-analysis comparing proximal gastrectomy with double-tract-reconstruction and total gastrectomy in gastric and gas...
BACKGROUND: Proton pump inhibitors (PPI) may impact the absorption of vitamin B12. We performed a systematic review to ascertain if PPI use increases risk of vitamin B12 deficiency. METHODS: Electronic databases (PubMed, Embase, Scopus) were searched...
BACKGROUND AND AIMS: Childhood and adolescent obesity is a global public health concern. Obesity induces several metabolic disturbances. Several studies have explored the association of vitamin B12, folate, and homocysteine (Hcy) with obesity. This s...
BACKGROUND: Few randomised controlled trials (RCTs) have examined potential preventive agents in high-risk community populations. AIMS: To determine whether a mental health literacy intervention, the promotion of physical activity, or folic acid plus...
**Zhu et al., 2011** | J Clin Neurosci | Meta Analysis Zhu Ying, He Zhi-Yi, Liu He-Nan. Meta-analysis of the relationship between homocysteine, vitamin B₁₂, folate, and multiple sclerosis. J Clin Neurosci. 2011-Jul;18(7):933-8. doi:10.1016/j.jocn.201...
UNLABELLED: Moderate regular consumption of alcoholic beverages is believed to protect against atherosclerosis but can also increase homocysteine or dimethylglycine, which are putative risk factors for atherosclerosis. We aimed (1) to investigate the...
**Zhao et al., 2017** | Neurology | Meta Analysis Zhao Min, Wu Guangliang, ... Cai Yefeng. Meta-analysis of folic acid efficacy trials in stroke prevention: Insight into effect modifiers. Neurology. 2017-May-09;88(19):1830-1838. doi:10.1212/WNL.00000...
**Tsai et al., 2021** | J Am Coll Nutr | Meta Analysis Tsai Tsung-Yu, Lee Tsai-Hsien, ... Huang Yu-Chen. Serum Homocysteine, Folate, and Vitamin B12 Levels in Patients with Systemic Lupus Erythematosus: A Meta-Analysis and Meta-Regression. J Am Coll ...
OBJECTIVE: This systematic review and meta-analysis aimed to evaluate the vitamin B12 status and intake of Seventh-day Adventists following a plant-based diet and compare it with omnivore controls to investigate their susceptibility for vitamin B12 d...
**Yoo et al., 2025** | Nutr Neurosci | Meta Analysis Yoo Samantha, Montazeri Azita, ... Little Julian. Is there a causal link between folate status and schizophrenia? Evidence from genetic association studies. Nutr Neurosci. 2025-Aug;28(8):940-951. d...
**Nguyen et al., 2025** | Ann Med | Meta Analysis Nguyen Nhi Thi Hong, Chen Yang-Ching, ... Chao Jane C-J. Global prevalences of erythropoiesis-associated micronutrient deficiencies (iron, folate, and vitamin B12) among pregnant women: a systematic r...
**Green et al., 2007** | Cochrane Database Syst Rev | Systematic Review Green J, Dundar Y, ... Walley T. Pemetrexed disodium in combination with cisplatin versus other cytotoxic agents or supportive care for the treatment of malignant pleural mesothe...
**Malouf et al., 2008** | Cochrane Database Syst Rev | Systematic Review Malouf Reem, Grimley Evans John. Folic acid with or without vitamin B12 for the prevention and treatment of healthy elderly and demented people. Cochrane Database Syst Rev. 2008...
**Tsai et al., 2019** | J Am Acad Dermatol | Meta Analysis Tsai Tsung-Yu, Kuo Che-Yuan, Huang Yu-Chen. Serum homocysteine, folate, and vitamin B12 levels in patients with vitiligo and their potential roles as disease activity biomarkers: A systematic...
**Hawley et al., 2022** | Meat Sci | Systematic Review Hawley Aubree L, Liang Xinya, ... Baum Jamie I. The potential role of beef and nutrients found in beef on outcomes of wellbeing in healthy adults 50 years of age and older: A systematic review of...
**Zhao et al., 2022** | Front Aging Neurosci | Systematic Review Zhao Yan, Dong Xinyi, ... Li Sha. Blood levels of circulating methionine components in Alzheimer's disease and mild cognitive impairment: A systematic review and meta-analysis. Front Ag...
**Mazur et al., 2025** | Front Pharmacol | Systematic Review Mazur Marta, Ndokaj Artnora, ... Bourgeois Denis. Efficacy of sublingual and oral vitamin B12 versus intramuscular administration: insights from a systematic review and meta-analysis. Front...
BACKGROUND: Folates are vitamins essential to the development of the central nervous system. Insufficient folate activity at the time of conception and early pregnancy can result in congenital neural tube defects. In adult life folate deficiency has ...
Poor vitamin B₁₂ status may lead to the development of cognitive decline and dementia but there is a large variation in the quality, design of and results reported from these investigations. We have undertaken a systematic review of the evidence for ...
**Sukumar et al., 2016** | Am J Clin Nutr | Meta Analysis Sukumar Nithya, Rafnsson Snorri B, ... Saravanan Ponnusamy. Prevalence of vitamin B-12 insufficiency during pregnancy and its effect on offspring birth weight: a systematic review and meta-ana...
**Oussalah et al., 2017** | Am J Clin Nutr | Meta Analysis Oussalah Abderrahim, Levy Julien, ... Guéant Jean-Louis. Association of TCN2 rs1801198 c.776G>C polymorphism with markers of one-carbon metabolism and related diseases: a systematic review an...
**Sun et al., 2018** | Biosci Rep | Meta Analysis Sun Manchun, Sun Manyi, ... Shi Songli. Colorectal polyp risk is linked to an elevated level of homocysteine. Biosci Rep. 2018-Apr-26;38(2). doi:10.1042/BSR20171699 Several studies have reported an as...
**Wang et al., 2018** | J Altern Complement Med | Systematic Review Wang Li-Qiong, Chen Zhuo, ... Liu Jian-Ping. Zusanli (ST36) Acupoint Injection for Diabetic Peripheral Neuropathy: A Systematic Review of Randomized Controlled Trials. J Altern Compl...
**Prades et al., 2023** | Nutr Neurosci | Meta Analysis Prades Nuria, Varela Eva, ... Baeza Inmaculada. Water-soluble vitamin insufficiency, deficiency and supplementation in children and adolescents with a psychiatric disorder: a systematic review a...
**Batarbekova et al., 2025** | Asia Pac J Clin Nutr | Systematic Review Batarbekova Sholpan, Zhunussova Dinara, ... Imangaliyeva Altynay. Micronutrient status of patients with diabetic foot: A systematic review. Asia Pac J Clin Nutr. 2025-Aug;34(4):4...
**Authority**: European Food Safety Authority (EFSA) **Claim Type**: art13.1 **Substance**: vitamin-b12 **DOI**: 10.2903/j.efsa.2010.1459 **URL**: https://doi.org/10.2903/j.efsa.2010.1459
**Heinz et al., 2009** | Am J Kidney Dis | Meta Analysis Heinz Judith, Kropf Siegfried, ... Dierkes Jutta. Homocysteine as a risk factor for cardiovascular disease in patients treated by dialysis: a meta-analysis. Am J Kidney Dis. 2009-Sep;54(3):478-...
Showing top 50 of 237 sources, sorted by quality score.
Details
Vitamin B12
Overview
Vitamin B12 is a essential nutrient tracked in the biomedical knowledge base.
Also known as: cobalamin, methylcobalamin, cyanocobalamin, hydroxocobalamin, adenosylcobalamin
Role in Health
Detailed overview pending — this entity has sources compiled across multiple verticals.
Related Verticals
See sources-index for all verified sources referencing Vitamin B12.
Safety Considerations
Safety data extraction pending.
Sources
See linked source pages for full provenance.
Related Supplements
Frequently Asked Questions
What is Vitamin B12 and why is it important?
Vitamin B12 is an essential micronutrient that plays a critical role in DNA synthesis, methylation, and maintaining neurological health. It is vital for various bodily functions, including brain and nerve health.
Is Vitamin B12 effective for treating a deficiency?
Yes, there is strong evidence that various administration routes, including oral, intramuscular, and sublingual, are effective in treating Vitamin B12 deficiency. This is one of the most well-supported uses for the supplement.
Can Vitamin B12 help with brain function and memory?
There is moderate evidence suggesting that B12 levels are associated with cognitive function, particularly in Parkinson's disease. Research also indicates it may impact symptoms of fatigue and depression.
Is Vitamin B12 important during pregnancy?
There is moderate evidence that Vitamin B12 plays a role in neural tube development and overall maternal and child health outcomes. Ongoing research is currently investigating its specific role in relation to folate.
Does Vitamin B12 affect heart and metabolic health?
There is moderate evidence for associations between B12 levels and the risk of metabolic syndrome, coronary heart disease, and intracranial aneurysms. However, more research is needed to fully understand these links.
How much Vitamin B12 should I take every day?
The recommended dietary allowance (RDA) for adults is 2.4 mcg per day. While specific therapeutic doses for treating deficiency were not explicitly detailed in the research, following the RDA helps maintain healthy levels.
Are there any side effects or drug interactions with Vitamin B12?
There are currently no documented drug interactions or specific contraindications for Vitamin B12 in the available research. However, you should always consult a healthcare professional before starting a new supplement regimen.
Answers generated from research evidence. Not medical advice.