Private vitamin b12 injection service in Islington Islington Clinic B12 Injection sites + How to use B12 Shots Safely Do you follow a vegan diet? Did you know that vitamin b12 is mainly present in animal based products so those following a strict plant based are more likely to be deficient in vitamin Vitamin b12 deficiency can cause several symptoms including, extreme tiredness, lack of energy, mental fog, and changes in mood and balance. Find out more about b12 deficiency and our private vitamin b12