Can you overdose on vitamin B12?

It is quite rare that a person might suffer from Vitamin B12 overdose. As this is a water soluble Vitamin most of the excess of vitamins is flushed out by the body and dissolved in time. However, there have been cases when person have suffered from Vitamin B12 overdose. This rise of this vitamin in a human body can lead to imbalance of kidney function.

The other types of symptoms include itchy sensation and numbness in different parts of the body, giddiness, headache and abnormal functioning of heart. In extreme cases, it can lead to tingling sensation in the body.

It is a water soluble vitamin, but moreover, taken orally, it is destroyed by the liver in short order once swallowed. This is because its chemical name is cyanobalamine. See that "cyano" portion of the name? One of the constituents of the molecule is cyanide. The liver is not going to tolerate its presence in the gut for very long. The way we obtain B-12 naturally is from organisms on meat. We can't ingest it directly by eating food, but these organisms make it as a byproduct of their metabolism in our gut. We can take B-12 in a sublingual form that dissolves under the tongue, and into the blood stream. It can also be taken in the form of a nasal gel that absorbs in the nasal mucosa. Then there is a fairly painful intramuscular injection that must be given at a doctors office on a regular basis. Were one attempting to deliberately OD on it, one would have to be awfully determined. Taking mega doses of it for increased energy would be a waste of time, money and effort. You will find it on the labels of energy drinks, but obviously it is more something to place on the label, than something that gives one energy by drinking it. Conceivably, it might be possible to OD on the chemicals that it is placed with, which are vehicles to make it able absorb by whatever route it is administered, but even that is a stretch.

Not really. It's water soluable, but the other stuff you take with it might be.