Vitamin B12 for Athletes: Dosing and Evidence (2026): The Short Answer Vitamin B12 (cobalamin) is essential for red blood cell production, oxygen delivery, and nerve function, all of which directly affect endurance performance
The B12 even taken in large doses is considered risk-free and safe
Certificate of Completion Receive a certificate confirming completion of professional Vitamin B12 Injection training, suitable for insurance purposes (subject to your insurers requirements)
Researchers are accordingly advised to refrain from administering 5-amino-1MQ indefinitely
What to Expect Before Getting a B12 Shot A nurse or doctor will confirm your deficiency Injection is usually given in the shoulder Slight pinch or sting for 23 seconds Possible brief dizziness or tingling Pre-shot tips: Eat something beforehand Wear loose clothing Stay seated for 10 minutes after What to Expect After Getting a B12 Shot Slight soreness at the injection site Redness or bruising (rare but not harmful) Headache or tiredness in the first 24 hours Most feel normal or better after 12 days Aftercare: Drink water Avoid strenuous activity if dizzy Monitor for swelling or allergy signs Alternatives to B12 Injections: Supplements and Food Sources Not everyone wants or needs a shot
When you lack cobalamin in your diet, it can lead to a range of neurological, physical, and psychological issues, with fatigue being only one symptom