My Account   |   View Cart
Phone Number for Health Supplements

Vitamin B12 Overdose


Question Details

 Hello there Doctor, After I run out of my current supplements I am going to be interested in ordering certain items from your site however I first have a question about Vitamin Poisoning. I hear too much of a vitamin can be bad? Is this true? Particularly I need to know about B Vitamins, even more specifically B12. I would like to know how much of this vitamin if any can be harmful. Perhaps you could send me it in mg/or daily value? If you could please find this out for me I would be FOREVER grateful.



 It is true that certain vitamins can be harmful for you if taken in excessive amounts.  This is particularly true for the fat soluable vitamins (A, D, E and K).  This is due the fact that they will build up in the fat tissue and potentially to toxic amounts if consumed in too great of quantities.  One must be careful with dosing particularly with vitamin A and vitamin D as these have the greatest potential for toxicity amongst the fat soluble family.  I remember an interesting statement about this...."Make sure you never eat polar bear liver".  Sound odd but because polar bears eat so much fat from animals they concentrate huge amounts of Vitamin A in thier livers.  So much, that if you ate polar bear liver you would die due to Vitamin A toxicity.

Now lets get to your question about B-vitamins.  These are thought to be amoung some of the safest vitamins with relativly low potential for toxicity.  Vitamin B6 can be toxic to the nerves if taken at over 300mg per day and Vitamin B3 (Niacin) can cause an upleasant reaction of flushing if taken in too high a dose although sometimes this is necessary for it to have theraputic action.

B12 is commonly given in doses much higher than the RDA (2.4 mcg (micrograms)) without known toxicity.  Most B12 supplements will provide at least 2,000 mcg of B12 and some deliver as much as 5,000mcg.  There has been no scientific evedence demonstrating any significant toxicty when given at this level.  Currently no tolerable upper limit of B12 has been set by The Food and Nutrition Board indicating this lack of toxic effects.  If you are considering taking a basic B12 supplement you should have nothing to worry about in regards to toxicity.

In Health



Back to all Questions     View More by Dr. Kevin Passero

Lead Medical Director

As a certified and fully trained Naturopathic Doctor, Passero has trained and preceptored with some of the nation's leading doctors in the field of natural medicine, working under the guidance of MD’s, Chiropractors, Naturopaths and Acupuncturists. Furthermore, he is currently the Vice President of the Maryland Association of Naturopathic Physicians.

View Profile


The products and the claims made about specific products on Vitabase.com have not been evaluated by the United States Food and Drug Administration and are not intended to diagnose, treat, cure or prevent disease. The information provided by Vitabase is for informational purposes only and is not intended as a substitute for advice from your physician or other health care professional or any information contained on or in any product label or packaging. You should not use the information on Vitabase.com for diagnosis or treatment of any health problem or for prescription of any medication or other treatment. You should consult with a healthcare professional before starting any diet, exercise or supplementation program, before taking any medication, or if you have or suspect you might have a health problem. Neither Vitabase nor Dr Passero will be liable for negative outcomes of supplements that are taken as a result of information given on Vitabase.com.