How Soon Do You Feel Less Tired After a B12 Injection? I Feel Tired All the Time. Do I Need a B12 Shot?: Shawn Veiseh, M.D.: Family Medicine B12 Injection Dosage and Frequency: 7 Essential Guidelines for Adults Liv Hospital Feeling tired, foggy, or run down? It could be a B12 deficiency Weekly B12 injections help support: Increased energy + reduced fatigue Sharper focus + better mood Boosted Why Vitamin B12 injections could be the boost you need Physio Edge If you've been feeling tired no matter how much sleep you get this could be your sign Vitamin B12 is essential for so many functions in the body, especially when it