Side Effects of B-12 Shots

Your body needs vitamin B-12 or Cobalamin. It helps in DNA production and in developing healthy nerve and red blood cells. It helps your body use fats and carbohydrates for energy. A lack of this vitamin can case you to feel fatigued. In more serious cases you can develop anemia, stomach problems and nerve damage. If you are feeling run down you may be tempted to take a B-12 shots to help. While B-12 injections are usually well tolerated, there can be mild and serious side effects if you inject too much.

Injection Site Problems

• Taking injections of B-12 can lead to redness, warmth, pain and swelling at the injection site. This should subside, but make sure you call your doctor if these symptoms become worse, or the swelling or sensations of warmth spreads to other areas of the body.

Hypokalemia

• While getting injections of B-12, your levels of potassium may become too low. If this occurs you may experience muscle cramping and weakness. Leg pain and numbness can also occur.

Cardiovascular Symptoms

• B-12 injections can cause irregular or rapid heartbeats and palpitations. In severe cases you could experience chest pain, shortness of breath, weakness on one side of the body and other signs of a stroke.

Allergic Reactions

• Allergic reactions to B-12 injections are rare. Look for symptoms of rashes that are itchy and swollen, rashes on the face, throat or tongue, severe dizziness or trouble breathing.

Other Symptoms

• Taking B-12 injections can cause diarrhea, nausea and upset stomach. Rapid weight gain, extreme thirst and frequent urination have also been reported.