B12 Injection Frequency: How Often Should You Get a B12 Shot? Liv Hospital A little insight to the importance of the b12 injections. My client hadn't been feeling well & had some bloods done with her GP. The results identified a severe deficiency in b12. 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 How often should vitamin B12 injections be administered and how frequently should laboratory monitoring be performed? B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics How often do you obtain B12 injections for weight loss?