Excessive Intake of Vitamin B Supplements

Symptoms and Treatment

Excessive intake of vitamin B supplements, particularly vitamin B6, can lead to adverse health effects. When consumed at doses exceeding 500 mg daily, or even 250 mg according to some data, for an extended period, it can result in peripheral neuropathy, skin disorders, dizziness, nausea, and increased sensitivity to ultraviolet radiation.

For example, intake of vitamin B3 (niacin) supplements at doses ranging from 500 to 3000 mg daily has been associated with symptoms such as nausea, vomiting, itching, skin flushing, numbness, muscle pains, and cardiovascular disturbances (arrhythmias, orthostatic hypotension).

Moreover, excessive intake of vitamin B5 (pantothenic acid) can cause dehydration, while vitamin B6 overdose may manifest as coordination disturbances, altered consciousness, seizures, and increased acidity of gastric fluid.

Excessive intake of vitamin B9 (folic acid) has been linked to leg cramps and allergic reactions. Additionally, a study conducted by researchers at Johns Hopkins Institute (USA) in 2016, based on medical and statistical data from 1998-2013, found that excessive consumption of folic acid and vitamin B12 during pregnancy, at rates 2-3 times higher than normal, increased the risk of autism in children, especially when “supra-protection” occurred in the third trimester. Furthermore, vitamin B12 increases blood clotting, thereby raising the risk of thrombosis.

Severe symptoms of vitamin B overdose include kidney and liver failure, fatty liver, pulmonary edema, anaphylactic shock, exacerbation of gastrointestinal and cardiovascular conditions, among others.

It is noteworthy that the symptoms of vitamin B excess often resemble or even replicate those of deficiency.


Any suspicion of vitamin deficiency or excess, including excess vitamin B, requires a thorough analysis of the individual’s diet, lifestyle (such as excessive alcohol consumption, chronic stress exposure, etc.), medical history (age, gender, previous or chronic illnesses), and particularly the medications and dietary supplements currently being taken. Diagnostic measures may include laboratory tests and diagnostic tools.


In case of evident disturbances in the central nervous system, immune system, or cardiovascular system, the patient should be hospitalized. Initial measures involve toxin elimination and identification of the causes of vitamin B excess. Subsequently, steps should be taken to achieve a balance in vitamin intake and eliminate risk factors, with symptomatic treatment as necessary.

In conclusion, while vitamin B supplements play a crucial role in maintaining health, their excessive intake can lead to various adverse effects. Therefore, it is essential to ensure a balanced intake of vitamins and closely monitor their consumption to avoid potential health risks.