Question:
How much B-12 is too much?

I have been taking 1 - 1000 mcg B-12 tablet daily, but was reading where Doctor Bodner says his patients get a multi-vitamin with just 6 mcg's of B-12. Am I taking too much? What will the affects be if I continue at this rate? Thanks,    — Lori D. (posted on September 24, 1999)

September 25, 1999
As far as I know, vitamin b12 is safe, 1000 mcg per day would not be toxic. It is a 'hell of a lot' though. Patients who have total gastrectomies can easily get by with 1000 mcg injected per 6 months. Why don't you ask your doc for a serum B12 level to see how much you are absorbing. My guess is that it will be off the scale high. Then you might consider 'cutting back'
   — Bruce B.

September 25, 1999
I get a monthly B12 shot as per my doc's recommendation. Seems like that's preferable to trying to take it by mouth and guessing what amount you are actually absorbing. Eventually I'm going to learn how to give it to myself at home so I won't even have to go to the doctor's for it. Might be something for you to consider.
   — Carol M.

September 25, 1999
Speak to your own doctor who know your case and your blood work results and what you specifically need. That is the only way to determine just how much B-12 you need. My B-12 levels came back low and I am on B-12 shots monthly now. Good Luck!
   — Sherrie G.

September 25, 1999
Hi Lori- Jan Terry here. I don't have an answer to your B-12 question but was wondering if you do find out the answer if you would pass along the info. to me. I just recently found out that my B-12 and iron are low. I have to take b-12 shots weekly for the next month, then check the levels again and go from there. I have been told to get Multi vitamins, Vit.C and take Iron 2x/day. Thanks for any answer you may have. You can E-Mail me at [email protected] Thanks.
   — Jan T.

September 25, 1999
I don't think you can overdose on B-12...but..since no one knows HOW B-12 is absorbed post operatively..or even if it IS if you are taking it orally, you might want to pursue the shot..they are very simple to give to yourself and very inexpensive. If you arent absorbing it properly, deficiencies won't show up for years...there is a lot of info about B-12 at the following web sites... http://www.wral-tv.com/features/healthteam/1998/0122-b12-deficiency/ <--interesting info http://www.shianet.org/~elf/B-12.html <---info about the nose spray form of B-12...seems like it might be effective! http://www.eagle-min.com/faq/faq115.htm <---this is an INCREDIBLY informative article about how B-12 is stored in the liver....I've copied some of it here for anyone who doesn't want to go to the web site....if you want to read the whole article...please DO! note the last line of the part I've copied here!!! Vitamin B-12 (cobalamin), stored in the liver, is a co-factor for two coenzymes. Methyl-cobalamin catalyzes methyl group transfer from a folic acid co-factor to form methionine. The unmethylated folate co-factor then participates in single carbon reactions for nucleic acid synthesis. Thus some symptoms of vitamin B-12 and folic deficiencies are similar. The B-12 coenzyme deoxyadenosylcobalamin catalyzes amino and fatty acid breakdown. VITAMIN B-12 Deficiencies: Stages of deficiencies include: I (early) - lower serum holotranscobalamin (holoTC II) (<60 pg/ml); II - lower serum vitamin B-12 (<300 pg/ml) and holoTC II (<40 pg/ml); III -serum vitamin B-12 < 200 pg/ml and holoTC II <40 pg/ml, neutrophil hypersegmentation, elevated homocysteine and methylmalonic acid; and IV (severest) - also megaloblastic, macrocytic anemia. Around Stage III (before anemia) there may be potentially irreversible demyelination of spinal cord, brain and optic and peripheral nerves which produces peripheral neuropathy progressing to subacute combined degeneration. Early symptoms may be dementia, poor attention span and depression. The stomach secretes intrinsic factor that binds vitamin B-12 and mediates its absorption at receptor sites in the ileum. Inadequate intrinsic factor secretion occurs in pernicious anemia, an autoimmune disease. In the elderly, atrophic gastritis is commonly associated with vitamin B-12 malabsorption and deficiency. Because the absorbed vitamin is secreted in bile and subsequently reabsorbed, deficiency symptoms can take 20 years to develop from low intakes, e.g., in strict vegetarians. However, in malabsorption, deficiency occurs in months or a few years because absorption from both the diet and enterohepatic circulation is impaired. De
   — Deanna D.

September 25, 1999
My doctor recommends sublingual b12 because it is absorbed much easier than oral. Give it a try!
   — miles B.

July 17, 2000
I am a pharmacy student and also 8 weeks post-op of an open RYN :) I began taking the sublingual B12/folic acid a week ago due to nerve pain in my back and legs. The sublingual is 1000mcg, and is absorbed instantaneously. Your body will take what it needs and the rest will be excreted in the urine, no need to worry that you are overdoing it.
   — lizp100