The Average Person's Vitamin B12 Levels. Part of the series: Heal the Body With Natural Remedies. Vitamin B12 is the largest and most structurally complicated vitamin, and even though it's water soluble, it can actually be stored in the liver for years. Find out about the average person's vitamin B12 levels with help from a Holistic Healer, medical intuitive, and the founder of Transformation Thrive in this free video clip.