do vitamin b12 injections cause constipation Are Shots Right for You? Vitamin B12 shots: Uses, benefits,

1 2 Annual Review of Nutrition

It is best to use different injection sites now and then to minimize pain and inflammation

Taking vitamin B12 on your own can cause serious problems

When to seek medical advice: Persistent or worsening injection site reactions (increasing redness, warmth, or discharge suggesting infection) Severe or persistent headaches Chest pain or palpitations Unexplained muscle weakness or cramps New or worsening neurological symptoms despite treatment Unexpected bleeding or bruising For non-emergency concerns, contact your GP or NHS 111

However, some patients may experience mild swelling and redness at the injection site, upset stomach, or light headedness