Feeling tired once in a while is normal. Maybe you did not sleep well, had a long day at work or college, or simply need some rest. But when tiredness stays for weeks and you cannot understand why, it may be worth looking into. Low B12 can cause tiredness, weakness and other changes in the body. As the deficiency gets worse, some people may develop tingling in their hands or feet, trouble concentrating, memory problems or balance issues. The symptoms are not the same for everyone, which is one reason B12 deficiency can be missed.
