Key Takeaways

B12 shots work fast but don’t last long. Most leaves your body within a day, though some is stored in the liver.

Regular injections may be necessary to maintain steady levels, especially if you have difficulty absorbing B12.

Vitamin B12 helps keep your nerves, blood cells, and energy levels healthy. If your levels are low, your healthcare provider may recommend B12 shots to boost them. How long the vitamin stays in your body depends on the dose, how often you get injections, and your individual needs.

How Long Do Vitamin B12 Injections Last?

B12 shots typically contain the synthetic form of B12 called cyanocobalamin .

After an injection, B12 will reach its peak level in about one hour.

Your kidneys eliminate most of a B12 shot (50% to 98%), with most being eliminate

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