Is Cyanocobalamin Poisonous?

Mon, 18 Aug 2025 11:46:27 +0000

Are you taking B12 injections and wondering if your cyanocobalamin B12 injection is poisonous? My name is Dr. Terranella, and in this video, we're going to look at different types of B12 and specifically the cyanocobalamin molecule, how it may be poisonous or problematic for you, and also the other side of it, when it's probably not a problem.
So, there are a few different types of B12.

But the most commonly used is cyanocobalamin. So, I wanted to look into this question because many people do use cyanocobalamin and ask if it is poisonous. Cyanocobalamin does contain a small amount of cyanide, and some people get worried when they find that out. And probably they should because cyanide is very toxic. Now, while cyanocobalamin is generally considered very safe, and many people do take it without any adverse problems, it does contain cyanide, which is a toxic substance. It is difficult to estimate how much cyanide is in each injection, but we can do some estimations to get a rough idea of how toxic or poisonous it could actually be.

All right, so the most common dose of B12, whether it's cyanocobalamin or any other cobalamin, is about 1,000 micrograms. Sometimes you'll do that once a week, maybe a little bit more in the beginning, and then as you go on, usually about once a month. So, if you're doing 1,000 micrograms, which is about 1 mL a week, how much cyanide are you actually getting?

First thing to note about cyanocobalamin is that it is a very stable structure. The cyanide molecule is bound to the cobalamin molecule very tightly. So, in order for you to get cyanide, it has to dissociate.

This will happen when that cyanocobalamin is converted into methylcobalamin, hydroxycobalamin, or adensylcobalamin, all of which are more functional forms of the vitamin B12 molecule. So, once that cyanocobalamin dissociates, you still have the cyanide molecule there, which can then attach to a potassium or a sodium molecule.

So, for every 1,000 micrograms of cyanocobalamin, you might yield about 1 microgram of cyanide. This is, again, something you might do once a month or on the high end, once a week. But cyanide is usually toxic in the several milligrams. So, you have a very small amount that you're going to yield from your injection, which is maybe 1 microgram versus several milligrams on the side of an actual toxic or major detrimental effect. If you get up to like 100 milligrams, that's what's going to be lethal.

Some estimates would be a little bit less, but of course it does depend on your size, the administration of it, and other susceptibility factors that you might have.

All this to say that it's actually pretty hard to get a toxic effect from cyanocobalamin. Part of that is because only small amounts are yielded of cyanide for each injection, and it's also a very stable molecule. Now, you might say to yourself, "Well, I don't really care if it's a small amount of poison. I don't want any poison in my body," and that's definitely a fair assessment as well, especially if you're in a more compromised health state. Most of the time when our health is compromised, it's coming from problems within the mitochondria. In particular, with cytochrome C and other parts of the electron transport chain. Well, cyanide is particularly toxic to cytochrome C and the whole electron transport chain.
So if you're having health problems, you're probably having mitochondrial problems, and this is not going to help that situation. In addition, most of us do have the ability to eliminate cyanide in small amounts when there's small amounts at a time, and therefore it gets eliminated before it causes any problems.

But in people that are in a more compromised health state, part of the problem is with toxic overload. detoxification systems are taxed or overrun. The cells, tissues and mitochondria are not able to eliminate even small amounts of toxins like cyanide when they're already overloaded.

So in a case like that, even small amount of cyanocobalamin might be problematic for someone. So now back to our question, Is cyanocobalamin poisonous. Well, I think it depends on what we mean by poisonous. There's certainly no instance where I can think of where cyanocobalamin has an injection to support your overall B vitamin status would actually be lethal or majorly problematic to your health. There are certainly cases in patients where I would think adding something like this could be more compromising to their health because they have problems with their mitochondria or electron transport chain.