VEI IV · Vitamin B12

Checking for a deficiency before supplementing:
vitamin B12 injections

Vitamin B12 injections replenish this vitamin through an intramuscular shot when a blood test shows a deficiency or when absorption is difficult. Vitamin B12 is needed to make red blood cells and maintain nerve function, so a deficiency can cause anemia, fatigue and tingling in the hands and feet. At VEI Clinic, we also decide after your consultation whether an injection containing a combination of B vitamins is suitable.

VEI Clinic, Gangnam — VEI IV · Vitamin B12

Why Vitamin B12 Levels Can Be Low

Vitamin B12 is found in meat, fish, eggs and dairy products. It needs to bind to a substance made in the stomach to be absorbed. A deficiency can therefore develop from absorption problems as well as a plant-based diet that provides little B12.

A prolonged deficiency can cause anemia, leaving you easily short of breath and tired. Nerve symptoms such as tingling in the hands and feet or memory problems can also occur. Symptoms alone are not enough to tell, so we check with a blood test.

Previous surgery to remove part or all of the stomach, or atrophic gastritis
Long-term use of the diabetes medication metformin or acid-suppressing medication
A long-term diet with very little meat, fish or dairy
Reduced absorption with older age

Injections and Oral Supplements

If absorption is normal, oral supplements are often enough. We recommend injections when absorption is difficult or levels need to be replenished quickly, then recheck your level to decide on a maintenance plan.

B-Complex Injections

Some injections contain several B vitamins together, such as B1, B2, B6 and B12. They are used as supplements when food intake is poor, but there is insufficient evidence that they relieve fatigue in people without a deficiency.

Trace Element Injections

There are also injections containing trace elements such as zinc, copper, manganese, selenium and chromium. These are used to replenish deficiencies caused by prolonged poor food intake or absorption problems. We do not recommend them during pregnancy because their safety has not been adequately established.

Precautions and What to Expect

Pain or swelling may occur at the injection site. Rarely, hypersensitivity reactions such as a rash can occur. Your urine may temporarily become darker after a vitamin B12 injection.

History and blood tests: reviewing symptoms, diet and medications, then testing for vitamin B12 deficiency and anemia
Consultation: choosing injections or oral supplements and deciding on the interval
Injection: a brief observation period after the intramuscular shot
Retesting: checking your level again to decide on a maintenance plan

The VEI Clinic Approach

An internal medicine specialist confirms deficiencies through test results and supplements only what you need. If your levels are normal, we start with advice on diet rather than injections.

FAQ

Frequently asked questions

Who needs vitamin B12 injections?

They are needed when a blood test confirms a deficiency or when absorption is difficult because of stomach surgery or long-term medication use. If your level is normal, an injection is often unnecessary.

Will they relieve fatigue?

If your fatigue is caused by a vitamin B12 deficiency, it may improve after supplementation. Without a deficiency, an improvement in fatigue is unlikely.

How often do I need an injection?

The initial interval is shorter depending on the severity of the deficiency. As your level rises, we space injections farther apart or switch to oral supplements. The specialist decides based on your test results.

Is this the same as a multivitamin injection?

A vitamin B12 injection contains one vitamin, while a B-complex injection contains several B vitamins. We choose based on your goals and test results.