The short answer is no, cyanocobalamin won’t kill you. The long answer will take a little more time to explain…
If this is the first time you’ve been on the site, it’s probably worth taking a quick look at our explanatory post about what vitamin B12, methylcobalamin and cyanocobalmin actually are. Otherwise the rest of this post probably won’t make a whole lot of sense!
What’s The Problem?
One of the most common arguments against using cyanocobalamin in vitamin B12 supplements is that it isn’t a biologically active form of the vitamin i.e. your body has to convert it before it can use it. This conversion is generally from cyanocobalamin to methylcobalamin. But because of the chemistry involved, this process releases a cyanide molecule into your body.
Cyanide is probably the most well-known poison on the planet, featuring in everything from James Bond films to the horrific gas chambers of Nazi Germany. So it makes sense that intentionally ingesting something that will release cyanide into your body might not be the best idea.
How Dangerous Is Cyanocobalamin?
We agree that cyanocobalamin isn’t the best choice, but for lots of other reasons as well (see our popular Methylcobalamin vs Cyanocobalamin article). The truth is that the amount of cyanide that enters your bloodstream when you take B12 supplements containing cyanocobalamin is really quite small. So little in fact that it’s not really worth worrying about. That little bit of cyanide doesn’t necessarily mean that cyanocobalamin is dangerous.
There are a number of common foods that will also release similarly small amounts of cyanide into your body. There’s a reason that the breath of someone who’s just taken cyanide smells like almonds. Apples are another classic example – when your body breaks down apples, cyanide is released. But no one ever tries to argue that apples are unhealthy!
Is It Possible To Overdose?
There’s no scientific evidence that vitamin B12 has any negative health effects even in studies where subjects have been given huge dosages for years at a time. Overdosing shouldn’t ever be a problem with B12.
If you’re taking enough supplements for the cyanide in cyanocobalamin to cause you serious problems, you’ll have some other serious problems too. This is especially true if you’re taking a multivitamin rather than straight vitamin B12 supplements.
Lots of the vitamins and minerals that your body requires in order to stay healthy are toxic in large quantities. B12 is not, but some of the other nutrients in multivitamins are. So if you were to take nothing but multivitamins to get a high dose of vitamin B12, you’d most likely be overdosing on some of the other ingredients.
We still recommend that you make sure your B12 supplement contains methylcobalamin (for all the reasons outlined in this link), but lots of people will still choose the cheaper, more readily available option of cyanocobalamin supplements. And while they may not be perfect… no, they’re not going to kill you!
From top to bottom, images are courtesy of zdiviv, m_bartosch, and renjith krishnan, all at FreeDigitalPhotos.net.