B12 injections are typically administered intramuscularlyusually in the upper arm or thigh
Before using this medication, speak with your doctor or pharmacist about your medical history, especially of low potassium, gout, blood disorders (polycythemia vera), eye disorders (Lebers disease), or other vitamin or mineral deficiencies
Before taking any new medication, either prescription or over-the-counter, check with your doctor or pharmacist
Depending on what is in the injections you receive, you could experience the following: Allergic reaction Anxiety Constipation Diarrhea Fatigue Headache Increased heart rate Insomnia Nausea Vomiting It is of note that anxiety, an increased heart rate, and insomnia typically occur only after receiving injections that contain medications like phentermine