Is cyanocobalamin a dangerous form of Vitamin B12?

by (2557) Updated August 10, 2013 at 10:03 PM Created September 19, 2010 at 7:53 AM

Cyanocobalamin is one of the forms of Vitamin B12 (cobalamin). The other forms are methylcobalamin and hydroxocobalamin. The latter two are more natural forms, I think.

Cyanocobalamin is basically a cyanide molecule attached to a B12 molecule. I was shocked to hear that. It's now ubiquitous in the food supply as the cheapest form of B12, available in fortified foods and multivitamin supplements.

Cyanocobalamin is an especially common vitamer of the vitamin B12 family. It is the most famous vitamer of the family, because it is, in chemical terms, the most air-stable. It is the easiest to crystallize and, therefore, easiest to purify after it is produced by bacterial fermentation. A form of vitamin B12 called hydroxocobalamin is produced by bacteria, and then changed to cyanocobalamin in the process of being purified in activated charcoal columns after being separated from the bacterial cultures. Cyanide is naturally present in activated charcoal, and hydroxocobalamin, which has great affinity for cyanide, picks it up, and is changed to cyanocobalamin. Thus, the cyanocobalamin form of B12 is the most widespread in the food industry.(Wikipedia: Cyanocobalamin)

Cyanide is the most scary thing I can imagine ingesting, yet nobody seems to be making much of a fuss over millions of people being supplemented with this to be "healthy".

There are certain people who need to be supplemented with B12...but I'm not convinced this is the safest way to do it, just because it's cheap.

I started thinking about cyanide and if maybe I was making too big a deal out of it. I understand that cassava root has been eaten traditionally even though it has cyanide in it, I read that soaking, fermenting and cooking helps get rid of it though. I also know that cyanide is in smoke so maybe humans can survive a little bit because humans have been making fire for a long time.

I just can't believe that it's the first time I heard of a cyanide connection with B12 supplementation.

I checked and Mark Sisson uses methylcobalamin in his supplements so maybe he is already aware. I've been wanting to post this for some time but I always worry that I sound frantic and paranoid when I post stuff like this. lol...

Total Views

Recent Activity

Last Activity
1440D AGO


Get Free Paleo Recipes Instantly

17 Replies

best answer

11363 · September 19, 2010 at 8:45 PM

Cyanides occur naturally in some foods, as noted in other answers. Hydrogen cyanide is also used rarely as a grain fumigant. Cyanide is an acute poison, but it does not cause chronic toxicity. Cyanide is toxic and potentially lethal to humans in an acute oral dose of 50 to 90 mg. "No cases of chronic intoxication in industry have been diagnosed. The possibility of chronic intoxication with HCN or cyanides is usually considered to be improbable." Ref: http://www.inchem.org/documents/jmpr/jmpmono/v65apr09.htm

Let's do the math to see how much cyanide is in B12 supplements. The RDA for B12 in adults is 2.4mcg per day ( http://www.nal.usda.gov/fnic/DRI//DRI_Thiamin/306-356_150.pdf). B12 supplements typically contain 100mcg of cyanocobalamin. The molecular weight of cyanocobalamin is 1355.39. The molecular weight of cyanide ion is about 26. So 1.92% (by weight) of a B12 supplement is cyanide. In other words, if you take 100mcg of B12 per day, you would only get about 2mcg (2 micrograms) of cyanide per day. By comparison, a single cigarette can deliver 40 to 100mcg of cyanide ( http://oehha.ca.gov/air/chronic_rels/pdf/74908.pdf ).

In summary, cyanocobalamin contains trace, non-toxic amounts of cyanide--not to worry.

100 · September 21, 2010 at 9:30 PM

I have pernicious anemia and I inject cyanocolobalamin monthly. Pernicious anemia results from a lack of sufficient IF (intrinsic factor) which results in inadequate B12 absorption. We produce less IF as we age and people with celiac disease (like me) sometimes produce indequate amounts. I was initially diagnosed in 2006 after months of worsening vertigo, short term memory loss, overwhelming anxiety, shortness of breath, exhaustion, loss of concentration and spatial dislocation. I was becoming mysteriously disabled. At first I injected it daily and my neurological symptoms resolved rapidly. It took longer for my energy to come back. I am profoundly grateful for that ruby red fluid. Without injectable B12, I am told I would I have to eat many pounds of liver a day to prevent dying after years of insanity. There are other sources of toxins--in food, water, and the air, that I am far more concerned about.

18909 · September 19, 2010 at 2:04 PM

Cyanocobalamin is not dangerous, it's not something to worry about. It is the most stable and easily purified from of vitamin B12. Having a form of vitamin B12 that is free from contamination and stable for long periods is important in a supplement. Small amounts of cyanide are commonly found in nature and are not harmful as our bodies can easily deal with them.

The amount of cyanide molecules in a normal dose of cyanocobalamin is really tiny. B12 is also only needed in tiny amounts compared to other vitamins.

The cyanide does separate from the cobalamin as it is converted to methylcobalamin by the body but this happens gradually as the vitamin is used. Heavy smokers can have enough cyanide in their body from the smoke that the separation of the cyanide molecule from the cobalamin cannot take place as efficiently and so they may not be able to make full use of this form of the supplement.

An interesting fact is that hydroxocobalamin is now used in cases of cyanide poisoning. The hydroxocobalamin joins with the cyanide molecules forming cyanocobalamin which is then safe and can be excreted by the kidneys.

30 · September 04, 2012 at 9:44 AM

It's really irrational to be affraid of cyanide in B12...

Have you ever eaten an Apple with its core and survived? That's because our body is well equipped to deal with natural ocuring cyanides, which are ubiquitous in many plant foods: fruits (rosacea), seeds (flax) and legumes. A single apple kernel contains several orders of magnitude more cyanide than a dose of B12 from cyanocobalamin. Even sweet almonds or cherrys contain trace amounts of cynide larger than the amount found in cyanocobalamin. Cyanides are perfectly safe substances as long as they don't exceed a critical dose. We have evolved a highly efficient enzyme system to get rid of them.

10 · August 01, 2013 at 12:27 AM

Its better to listen to Doctors who research this and have the labs and money and resources to find actual trace amounts of ingredients who tell us TRUE answers THAN rely on opinions and false hopes. Considering if you research homeopathics and come to find out the homeopathics to fight parasites uses small traces of ARSENIC yet poses no danger to human health, if anything helps your body out. The small traces of Cyanide in B12 and many other foods we eat are so small its not to worry. If you are to stop taking a high quality form of B12 in low doses because of the fear of Cyanide then you might as well stop eating 90% of the foods you eat. After doing research of this form of B12 i am actually impressed by how stable it is, how it can be even in a liquid form for high absorption so it doesn't require high dosages.

Also keep in mind, ALL OF THE WEBSITES that down talk this form of B12 all want you to buy some product they are selling. Ofcourse they are BIASED. I would rather listen to unbiased information from people who know what they are talking about than opinions. Opinions change, facts dont.

2241 · September 19, 2010 at 11:42 AM

You want the methyl form of b12

0 · May 29, 2013 at 7:54 PM

Worrying about cyanide in B12 is similar to worrying about chlorine in sucralose. I'm sure there is supporting documentation somewhere, but I assume the molecule is stable just like it is in sucralose.

0 · May 04, 2013 at 12:34 PM

What is the right dosage what is too much B~~12

0 · March 06, 2013 at 1:18 AM

Well if it comes to not taking ANY B-12 or taking a supplement that uses Cyanocobalamin i will take the supplement. As stated above, smoking one cigarette is way more dangerous than a weeks worth of the "cyanide." Anybody worried about this should also be making sure they wash all their fruits and vegetables before consuming, wear gloves around all day to avoid touching contaminants, wear a gas mask indoors and out (pollution and such), and take other precautions. Get the picture?? Unless you are purposely taking huge quantities of this stuff I don't think there is any need for concern. I will be switching to a supplement that uses a different form of B-12, but I would not throw out what I have now, and would use it again if its all I had.

0 · August 22, 2012 at 2:31 PM

I'm 24 and being diagnosed with PA. I find that after all my reading that hydroxcobalamin or methylcobalamin would be the better choices. Hydroxcobalamin actually leaches out cyanide and allows filtration through the kidneys. Methlcobalamin Doesn't contain it and doesn't leach it. Then read about cyanide from smoking that gives you an idea of chronic cyanide toxicity most people don't realize that either. The correlation there is it gives you an idea of low dose toxicity from cyanide. So personally I'd rather avoid the one with cyanide at all considering low dose toxicity can give me the same affects as my pernicious anemia. Lastly I'll say to avoid all this just don't eat the crap food. All the preservatives and all the mass produced food is killing you by throwing your immune system out of whack. If you read about autoimmune diseases you would understand that it probably could have been avoided with simple b12 and good diet. But these diseases go on years undiagnosed so that you end with a permanent problem instead of an easily fixable one. I've gone the majority of my life undiagnosed and being treated for its symptoms and the one thing, the most simple thing was checking my Cobalamin Serum (b12) levels and it was never done until a month and half ago after 12+ of issues. So if your feeling fatigued, anxious, depressed, body aches, lower back pain, headaches, eye pain(chronic), IBS like symptoms, have acid reflux disease, been diagnosed with ulcers and/or polyps you should get those levels checked first. These where all my symptoms and come to find it could have been all avoided with Cobalamin Injections. Don't let the salesman for pharmaceutical company aka your doctor push you around that is what I did I listened to them and not myself. The least you can do for yourself is demand that you get those levels checked.

0 · July 13, 2012 at 8:43 AM

Matthew, Zoe, Rachel and Ed's revised answers seem to be the truth on this one. While I don't like the idea of cyanide either.. it's concentrations seem to be so little in most supplement forms (what I'm researching tonight) and I no longer feel as if my multivitamin purchase on Amazon was the wrong choice :) Thanks for all of your input.. even Jamila's recent input too. I'll most likely shoot for the vitamin brand with "methylcobalamin" in it's ingredients in the future but I feel safer about my current cyanocobalamin multi-vitamin purchase..

16 · September 30, 2011 at 2:26 AM

I have taken Solgar B-Complex 50 For 5 years and am suffering bladder and Kidney problems. After doing some research on the product i found the problem:

Vitamin B-12 warning: Avoid cyanocobalamin, take only methylcobalamin I read the label on solgar and sure enough it contains the cyanide based poison added by the pharmaceutical companies. Here is information I found: Cyanocobalamin, in summary, is a low-grade, low-quality andslightly toxic (cyanide) form of vitamin B-12 that's used by all the cheap vitamin manufacturers. I recommend avoiding it completely. It won't kill you to take it, of course, but there's a better solution for B-12

The better choice: Methylcobalamin The proper form of vitamin B-12 to supplement is called methylcobalamin. This is the form that exists in nature, and it is pre-methylated, meaning it's ready for your biochemistry to put to immediate use. Methylcobalamin has several key advantages over cyanocobalamin:

  • Increased absorption
  • Better retention in tissues
  • Contains no toxic cyanide
  • Supports production of SAMe

As explained by Ed Sharpe: "The coenzyme form of vitamin B12 is known as methylcobalamin or methyl B12. It's the only form of vitamin B12 which can directly participate in homocysteine metabolism. In addition, converting homocysteine to methionine via methyl B12 generates an increased supply of SAMe (S-adenosyl methionine), the body's most important methyl donor."(http://www.health101.org/art_methyl...)

Every informed nutritionist knows that methylcobalamin is far superior to cyanocobalamin. Learn more:http://www.naturalnews.com/032766_cyanocobalamin_vitamin_B-12.html#ixzz1ZOfdz0Wy

What I take instead:

Methylcobalamin Liquid Vitamin B12 1,000 mcg I take only a few drops each week.

20469 · September 19, 2010 at 12:20 PM

Yeah really, the more I hear about this kind of thing, the more I am surprised that no one cares. I was recently researching almonds and apparently, bitter almonds naturally contain cyanide. They use bitter almonds in almond cookies to give a bit of a bitter taste. So they are putting cyanide in the cookies! Of course, since bitter almond is more expensive, they often substitute apricot pits instead. Apricot pits contain a substance called amygdalin which is metabolized in the body into cyanide! Again, more cyanide. And to think I used to really like almond cookies! It's hard to believe this stuff is legal and no one cares.

-2 · August 10, 2013 at 10:03 PM

Don't want to rain on anyone's cyanide-laced b-12 parade - but here's some serious indication that using Cyanocobalamin - it would seem that the body does have some real potential issues with Cyanocobalamin in processing and long term could be rather debilitating - Green Med Info doesn't sell any competing form of b12 - their database is both revealing and incredibly resourceful -


-2 · May 27, 2013 at 3:44 AM

Wow. Soooo this is what Wikipedia has to say:

"In addition to pesticide and insecticide, cyanide is contained in tobacco smoke, smoke from building fires and some foods, like almonds, apricot kernel, apple seeds, and cassava (also known as yuca or manioc). Vitamin B12 in the form of hydroxycobalamin, or hydroxocobalamin, may reduce the negative effects of chronic exposure, and a deficiency can lead to negative health effects following exposure.[2]

Exposure to lower levels of cyanide over a long period (e.g., after use of cassava roots as a primary food source in tropical Africa) results in increased blood cyanide levels, which can result in weakness and a variety of symptoms, including permanent paralysis, nervous lesions,[3][4][5] hypothyroidism,[4] and miscarriages.[6][7] Other effects include mild liver and kidney damage.[8][9]"

While it doesn't mention the daily amount for it to be dangerous, I don't think that it should be so quickly dismissed.

-2 · July 21, 2012 at 4:23 AM

thank you for this valuable info. my son is being poisoned by his vitamin b and his hands are turning blue and he is dizzy.

-2 · November 26, 2010 at 5:30 AM

I don't think that paleo diet is not dangerous, but diet companies are not working for some people's weight loss. Most Crossfit athletes and athletic people are in paleo diet.

Answer Question

Login to Your PaleoHacks Account