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 Injections near London Bridge Vitamin B12 Injections Dermatology Clinic in Wiltshire 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 How to self inject intramuscular vitamin B12 Overview Guy's and St Thomas' NHS Foundation Trust