Where does the body store vitamin B12?

People ask this when they want to know how quickly a B12 problem could begin, and whether a shot is the only way to fill the tank. Storage is the part of the answer that sets the pace.

In the liver, for years

MedlinePlus says the body stores vitamin B12 in the liver. It can store a few years' worth of the needed amount.

Why the size of the store matters

A reserve that lasts years means a shortfall in intake would take time to drain it.

The MedlinePlus encyclopedia entry on vitamin B12 covers the basics, and its companion page on vitamin B12 deficiency anemia covers what happens when the store runs low.

Weighing a B12 shot

It most often comes up while someone is weighing a B12 shot. Pieces such as the Medical News Today article on B12 shots for weight loss and the KSL.com article on whether B12 shots work for weight loss are examples of how the topic is framed for readers outside the clinic.

Testing before treating

Before a shot, ask for a level. A reserve measured in years is the reason to check where you stand first, not after a few weeks of guessing.

When symptoms show up

If symptoms appear, ask a clinician what is behind them instead of assuming diet alone.