Book in for your Vitamin B12 injections privately. Booster dose is 6 injections over 2 weeks for 150, then one injection every 8 12 weeks for 30 depending on your symptoms returning!!! Very Vitamin B12 Injection Dosage For Adults: A Comprehensive Guide. La Vie Med Spa 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. Common Injections Cheat Sheet Save for Ward Rounds! Insulin Diabetes Subcut 0.51 unit kg Vitamin B12 Deficiency Neuropathy IM 1001000 mcg Tetanus Toxoid