Redness, mild swelling, tenderness, or slight bruising can occur where the peptide is administered
Nausea or Upset Stomach: Some people may experience gastrointestinal discomfort, such as nausea, vomiting, or diarrhea, although these side effects are rare
As well, some people may have allergies or medical conditions that do not allow them to be a good candidate to receive vitamin B12 shots, such as kidney problems, low potassium levels, deficiencies in other vitamins such as iron or folic acid, or just an allergy or sensitivity to vitamin B12 itself
Interactions Vitamin B6 has been reported to have an adverse interaction with Vitamin K in presence of folic acid with an increase in INR (International normalized ratio)