What Exactly Is Vitamin B12?

Vitamin B12 (also known as cobalamin) is essential for your body to function properly. Without it, cell metabolism will be impaired and you will become very ill, with potentially life-threatening long-term effects if left untreated.

Cobalamin is the largest vitamin in existence, it's a deep red color, it will dissolve in water, and it's got a more chemically complex structure than any of the others, partly because of the cobalt atom at its heart. No human or any other plant, fungus or animal is capable of producing vitamin B12, so the only way to get it is through your diet.

Only bacteria can synthesize B12, but fortunately there isn't a plant or animal on Earth that doesn't have a host of bacteria living on it. This means that you will often ingest vitamin B12 through everyday foods, although animal products tend to have the highest concentrations of the vitamin.

There are several different kinds of vitamin B12. The form that is produced by bacteria is known as hydroxocobalamin, but humans can't use this directly. In fact, the only way that this is useful is if the body converts it to another vitamer, either methylcobalamin or adenosylcobalamin. It's also possible for the body to switch between these two different forms of B12 whenever it wants to.

Both methyl- and adenosylcobalamin are active forms of vitamin B12, which just means that your body can use them straight away, without any further conversion or chemical action being necessary. This is one of several reasons that supplements containing methylcobalamin are becoming increasingly popular, as the higher bioavailability of the compound is a great selling point.

The final form that B12 can be found in is called cyanocobalamin. Cyanocobalamin very rarely occurs naturally, and the only reason it exists in large quantities today is because scientists can synthesize it in laboratories.

Cyanocobalamin is cheaper and easier to produce in industrial quantities than any of the other types of vitamin B12, and so it is the most common kind in supplements. However, it is an artificial and synthetic product, which many people would rather not ingest.

Another potential problem makes itself known inside the body. Just like hydroxocobalamin, your body can't use cyanocobalamin straight away and has to convert it into one of the active forms of vitamin B12 first. The issue is that this conversion process will liberate a cyanide group into your body. You regularly ingest small amounts of cyanide in your diet anyway, but most people turn to methylcobalamin supplements the moment they find that their supposedly healthy tablets are actually releasing a poison directly into their bloodstream.