Vitamin B12 (cobalamin) and folate (vitamin B9) are vitamins that serve important functions in the human body. Folate is needed for development and growth of cells (including red blood cells) and synthesis 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, B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics What Does a B12 Shot Do for You? Vitamin B12 Deficiency