Vitamin B12 deficiency can cause symptoms like headaches, fatigue, depressive mood, gastrointestinal issues, and more. While vegetarians are at a higher risk of vitamin B12 deficiency, it can affect non vegetarians too. Check Taking Vitamin B12? Read this first. While B12 is often hailed as a safe energy and brain booster, many real users are reporting unexpected side effects including anxiety, insomnia, Fun Fact Friday! Ever wondered Why is my B12 injection red? All B12s are cobalamins they have a cobalt atom at the center of a special ring shaped molecule called Facial Signs of B12 Deficiency