B12 excess symptoms
Pro Research Analysisby 
Searched over 200M research papers
Symptoms of Vitamin B12 Excess
Introduction to Vitamin B12 Excess
Vitamin B12, also known as cobalamin, is essential for cellular metabolism, DNA synthesis, and neurological function. While deficiency in this vitamin is well-documented and can lead to severe health issues, the effects of excess vitamin B12 are less commonly discussed. This article explores the symptoms and clinical manifestations associated with high doses of vitamin B12.
Dermatological Symptoms: Acne and Facial Ruddiness
One of the documented cases of vitamin B12 excess involved a young woman treated with multiple daily doses of cyanocobalamin for pernicious anemia. After a total dose of 12 mg, she developed acne and facial ruddiness . These dermatological symptoms were unexpected and highlight the potential for skin-related side effects from high doses of vitamin B12.
Neurological and Psychiatric Symptoms: Anxiety, Palpitations, and Insomnia
In the same case, the patient also experienced neurological and psychiatric symptoms such as palpitations, anxiety, akathisia (a state of agitation), headache, and insomnia . These symptoms improved two weeks after discontinuing the vitamin B12 supplementation, suggesting a direct correlation between high doses of the vitamin and these adverse effects.
Cognitive and Psychiatric Manifestations
While vitamin B12 deficiency is well-known for causing psychiatric symptoms such as slow cerebration, confusion, memory changes, delirium, depression, and acute psychotic states , the effects of excess vitamin B12 on cognitive function and psychiatric health are less clear. A systematic review and meta-analysis found no significant effect of vitamin B12 supplementation on cognitive function or depressive symptoms in patients without advanced neurological disorders . This suggests that while deficiency has clear psychiatric implications, excess may not have a straightforward impact on cognitive or depressive symptoms.
Lack of Effect on Fatigue and Quality of Life
A randomized double-blind placebo-controlled trial investigated the effect of surplus oral vitamin B12 supplementation on fatigue in patients with Irritable Bowel Syndrome (IBS) or Inflammatory Bowel Disease (IBD). The study found no significant difference in fatigue levels, depression, or quality of life between the intervention group and the control group . This indicates that high doses of vitamin B12 do not alleviate fatigue or improve quality of life in these patient populations.
Conclusion
Excessive intake of vitamin B12 can lead to a range of symptoms, including dermatological issues like acne and facial ruddiness, as well as neurological and psychiatric symptoms such as anxiety, palpitations, and insomnia . However, the impact of high doses on cognitive function, depressive symptoms, and fatigue appears to be minimal or non-existent in patients without advanced neurological disorders Markun2021Scholten2017. These findings underscore the importance of cautious administration of vitamin B12, even though it is generally considered safe.
Sources and full results
Most relevant research papers on this topic
Toxicity induced by multiple high doses of vitamin B12 during pernicious anemia treatment: a case report
Multiple high doses of vitamin B12 during pernicious anemia treatment can cause unexpected and unusual side effects, such as acne, palpitations, anxiety, and insomnia.
What are the Psychiatric Manifestations of Vitamin B12 Deficiency?
Vitamin B12 deficiency can cause psychiatric symptoms such as slow cerebration, confusion, memory changes, delirium, depression, acute psychotic states, and reversible manic and schizophreniform states.
Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression
Vitamin B12 supplementation is likely ineffective for improving cognitive function and depressive symptoms in patients without advanced neurological disorders.
Cobalamin Deficiency: Clinical Picture and Radiological Findings
Vitamin B12 deficiency can cause various hematological, gastrointestinal, psychiatric, and neurological disorders, with symptoms ranging from anemia to neuropsychiatric disorders.
Surplus vitamin B12 use does not reduce fatigue in patients with Irritable Bowel Syndrome or inflammatory bowel disease: A randomized double-blind placebo-controlled trial.
Surplus vitamin B12 supplementation does not reduce fatigue in IBS or IBD patients, and has no positive effect on depression or quality of life.
Oral signs and symptoms in patients with undiagnosed vitamin B12 deficiency.
Undiagnosed vitamin B12 deficiency can cause oral symptoms, including glossitis, stomatitis, and mucosal ulceration, without causing generalized symptoms or macrocytosis.
DOI