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Vitamin B12
Also indexed as:B12 Vitamin, Adenosylcobalamin, Cobalamin, Cyanocobalamin, Hydroxocobalamin, Hydroxycyanocobalamin, Methylcobalamin
Vitamin B12 is a water-soluble vitamin needed for normal nerve cell activity, DNA replication, and production of the mood-affecting substance SAMe (S-adenosyl-L-methionine). Vitamin B12 acts with folic acid and vitamin B6 to control homocysteine levels. An excess of homocysteine is associated with an increased risk of heart disease, stroke, and potentially other diseases such as osteoporosis and Alzheimer’s disease.
- Reliable and relatively consistent scientific data showing a substantial health benefit.
- Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
- For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
This supplement has been used in connection with the following health conditions:
| Used for | Amount | Why |
|---|---|---|
Anemia and Vitamin B12 Deficiency | 600 to 1,000 mcg daily |  [3 stars] Taking vitamin B12 may help prevent and treat anemia. Deficiencies of iron, vitamin B12, and folic acid are the most common nutritional causes of anemia.
|
Depression and Vitamin B12 Deficiency | See a doctor for evaluation | [3 stars] Taking vitamin B12 can help counteract deficiencies related to depression. |
High Homocysteine (Vitamin B6, Folic Acid) | 400 to 1,000 mcg of folic acid daily, 10 to 50 mg of vitamin B6 daily, and 50 to 300 mcg of vitamin B12 daily | [3 stars] Vitamin B6, folic acid, and vitamin B12 all play a role in converting homocysteine to other substances within the body and have consistently lowered homocysteine levels in trials. |
Neuropathy (Vitamin B6, Folic Acid) | 2,000 mcg methylcobalamin (B12); 3,000 mcg methylfolate (B9); and 35 mg pyridoxal 5-phosphate once to twice daily | [3 stars] B vitamins, and vitamin B12 in particular, may be helpful in treating various types of neuropathies. People with type 2 diabetes taking metformin should be monitored for B12 deficiency. |
Type 1 Diabetes | 1,500 micrograms daily | [3 stars] Supplementing with vitamin B12 may improve symptoms of diabetic neuropathy. |
Age-Related Cognitive Decline (Vitamin B6, Folic Acid) | Refer to label instructions |  [2 stars] In women with cardiovascular disease or related risk factors and low dietary intake of folic acid, vitamin B6, and vitamin B12, supplementing with a combination of these nutrients may protect against age-related cognitive decline. |
Age-Related Cognitive Decline and Vitamin B12 Deficiency | Consult a qualified healthcare practitioner | [2 stars] Improved brain function among seniors has been observed after correcting vitamin B12 deficiency with injections, but oral vitamin B12 has not been studied for ARCD. People with ARCD should be tested for vitamin B12 deficiency.
|
Bell’s Palsy | Consult a qualified healthcare practitioner | [2 stars] Vitamin B12 injections have been shown to be beneficial for people with Bell’s palsy. |
Celiac Disease (Vitamin B6, Folic Acid) | 3 mg vitamin B6, 0.8 mg folic acid, and 0.5 mg vitamin B12 | [2 stars] Daily supplementation with a combination of vitamin B6 (3 mg), folic acid (0.8 mg), and vitamin B12 (0.5 mg) have been shown to help relieve depression in people with celiac disease. |
Chronic Fatigue Syndrome | Consult a qualified healthcare practitioner | [2 stars] Vitamin B12 deficiency may cause fatigue, but B12 injections have been reported benefits even without deficiency. A doctor should evaluate deficiency and whether B12 injections may help.
|
Hepatitis and Hepatitis C | Refer to label instructions | [2 stars] In one study, the addition of vitamin B12 injections to antiviral medications increased the proportion of patients in whom the hepatitis C virus was cleared from the body. |
Indigestion and Vitamin B12 Deficiency, Delayed Gastric Emptying, and Helicobacter Pylori Infection | 1,000 mcg daily | [2 stars] Vitamin B12 may be beneficial for people with delayed emptying of the stomach in association with Helicobacter pylori infection and low blood levels of vitamin B12. |
Low Back Pain (Vitamin B1, Vitamin B6) | Take under medical supervision: 50 to 100 mg each of vitamins B1 and B6, and 250 to 500 mcg of vitamin B12, all taken three times per day | [2 stars] A combination of vitamin B1, vitamin B6, and vitamin B12 may prevent a common type of back pain linked to vertebral syndromes and may reduce the need for anti-inflammatory medications. |
Macular Degeneration (Vitamin B6, Folic Acid) | 2.5 mg folic acid, 50 mg vitamin B6, and 1 mg vitamin B12 | [2 stars] In a double-blind study of female health professionals who had cardiovascular disease or risk factors, daily supplementation with folic acid, vitamin B6, and vitamin B12 significantly decreased age-related macular degeneration.
|
Male Infertility | 1,500 mcg daily | [2 stars] Vitamin B12 is needed to maintain fertility. Vitamin B12 injections have been shown to increase sperm counts. Men |
Migraine Headache | 1 mg daily | [2 stars] In a preliminary trial, vitamin B12 reduced the frequency of migraine attacks by at least 50% in 10 of 19 people with recurrent migraines. |
Osteoporosis and High Homocysteine | 1,500 mcg with 5 mg of folic acid daily | [2 stars] Homocystinuria, a condition associated with high homocysteine levels, frequently causes osteoporosis. By lowering homocysteine levels, vitamin B12 may help prevent osteoporosis. |
Schizophrenia and High Homocysteine (Vitamin B6, Folic Acid) | Take folic acid (2 mg), vitamin B6 (25 mg), and vitamin B12 (400 mcg) daily | [2 stars] People with schizophrenia who have high homocysteine levels may improve symptoms by supplementing with folic acid, vitamin B6, and vitamin B12. |
Sickle Cell Anemia and Vitamin B12 Deficiency | Consult a qualified healthcare practitioner | [2 stars] People with sickle cell anemia may be deficient in vitamin B12. Intramuscular vitamin B12 injections improved symptoms for patients in one study. |
Thalassemia and Vitamin B12 Deficiency | If deficient: 300 to1,000 mcg daily | [2 stars] Some studies have found people with thalassemia to be frequently deficient in vitamin B12, supplementing with the vitamin may help. |
Type 2 Diabetes and Diabetic Neuropathy (Vitamin B1) | Refer to label instructions | [2 stars] Taking vitamin B1 combined with vitamin B12 may improve symptoms of diabetic neuropathy. |
Type 2 Diabetes and Diabetic Neuropathy | 1 to 10 mg daily | [2 stars] Vitamin B12 deficiency is common in people being treated medically for type 2 diabetes. Supplementation can restore healthy levels and prevent dangerous long-term consequences of B12 deficiency. |
Urinary Incontinence (if deficient ) | See a doctor to test for deficiency | [2 stars] Vitamin B12 deficency can cause urinary incontinence that may be corrected with supplementation.
|
Vitiligo | Refer to label instructions | [2 stars] Studies have shown vitamin B12 to be effective at skin repigmentation in people with vitiligo. |
Alzheimer’s Disease | Refer to label instructions |  [1 star] Some researchers feel Alzheimer’s disease may be related to vitamin B12 deficiency. |
Asthma | Refer to label instructions | [1 star] In some people, asthma symptoms can be triggered by ingesting sulfites, a food additive. Pretreatment with a large amount of vitamin B12 reduced some children’s asthmatic reaction to sulfites in one trial. |
Atherosclerosis | Refer to label instructions | [1 star] Blood levels of the amino acid homocysteine have been linked to atherosclerosis and heart disease in most research. Taking vitamin B12 may help lower homocysteine levels. |
Bipolar Disorder | Refer to label instructions | [1 star] Vitamin B12 deficiency has been associated with both mania and depression. In one study, these symptoms cleared after treatment with B12 injections. |
Bursitis | Refer to label instructions | [1 star] Vitamin B12 injections have been shown to relieve symptoms of acute shoulder bursitis and decrease the amount of calcification in some cases. |
Canker Sores | 3 to 1,000 mcg daily | [1 star] Recurrent canker sores might be related to vitamin B12 deficiency, but research has shown that even without deficiency supplementing this vitamin may be beneficial.
|
Crohn’s Disease | Refer to label instructions | [1 star] Vitamin B12 is needed to repair intestinal cells damaged by Crohn’s disease. Supplementation may offset some of the deficiency caused by Crohn’s-related malabsorption. |
Dermatitis Herpetiformis and Vitamin B12 Deficiency | Refer to label instructions | [1 star] Supplementing with vitamin B12 can counteract the nutrient deficiency that often occurs as a result of malabsorption. |
Down Syndrome | Refer to label instructions | [1 star] People with Down syndrome may be deficient in vitamin B12 and may benefit from supplementation. |
Heart Attack | Refer to label instructions | [1 star] Taking vitamin B12 may reduce blood levels of homocysteine. High homocysteine levels have been linked to an increased heart attack risk. |
HIV and AIDS Support | Refer to label instructions | [1 star] In HIV-positive people with B-vitamin deficiency, B vitamins appear to delay progression to and death from AIDS. |
Hives | Refer to label instructions | [1 star] Vitamin B12 injections have been reported to reduce the severity of acute hives and the frequency and severity of outbreaks in chronic cases. |
Immune Function | Refer to label instructions | [1 star] A deficiency of vitamin B12 has been associated with decreased immune function. Restoring vitamin B12 levels may improve levels of immune cells. |
Insomnia | Refer to label instructions | [1 star] In two small preliminary trials, people with insomnia resulting from disorders of the sleep-wake rhythm improved after supplementing with vitamin B12. |
Lung Cancer | Refer to label instructions | [1 star] Together, folic acid and vitamin B12 help cells replicate normally. In one trial, smokers with precancerous lung changes who were given folic acid and vitamin B12 saw a significant reversal of their condition. |
Pain | Refer to label instructions | [1 star] Vitamin B12 appears to have pain-killing properties. In people with vertebral pain syndromes, injections of massive amounts of vitamin B12 have reportedly relieved pain. |
Phenylketonuria and Vitamin B12 Deficiency | Refer to label instructions | [1 star] Vitamin B12 is found almost exclusively in foods of animal origin, which are restricted on the PKU diet. Supplementing with vitamin B12 may correct a deficiency. |
Pre- and Post-Surgery Health | Refer to label instructions | [1 star] In one trial, a combination of vitamins B1, B6, and B12 before and after surgery prevented post-surgical reductions in immune activity. |
Retinopathy | Refer to label instructions | [1 star] In one study, adding vitamin B12 to the insulin injections of children with diabetic retinopathy helped relieve symptoms. |
Schizophrenia | Refer to label instructions | [1 star] People with schizophrenia may have low vitamin B12 levels. Supplementing with the vitamin may correct an imbalance and improve symptoms. |
Seborrheic Dermatitis in Adults | Refer to label instructions | as Vitamin B12 Injection[1 star] Vitamin B12 injections have been reported to improve adult seborrheic dermatitis. |
Shingles and Postherpetic Neuralgia | Refer to label instructions | [1 star] Vitamin B12 injections may relieve the symptoms of postherpetic neuralgia. |
Stroke and High Homocysteine | Refer to label instructions | [1 star] Elevated blood levels of homocysteine have been linked to stroke risk in most studies. Supplementing with vitamin B12 may lower homocysteine levels and reduce stroke risk. |
Tinnitus | Refer to label instructions | [1 star] Vitamin B12 injections may help reduce the severity of tinnitus in people who are deficient in the vitamin. |
Copyright © 2025 TraceGains, Inc. All rights reserved.
Learn more about TraceGains, the company.
The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2025.
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