If you're concerned about B12 shot side effects, you can relax. Unless you have an allergic reaction to the shots, you should not experience side effects of any kind. People who experience an allergic reaction to vitamin B12 shots will exhibit a rash, tightness of chest or difficulty breathing, but these reactions are quite rare. If you do experience these symptoms, you should tell your doctor right away. However, most people tolerate B12 shots quite well.
Vitamin B12 is water soluble, so your body will excrete most of the excess, making it very difficult to overdose. Your body will store some B12 in your kidneys, liver and other body tissues, but in general the body has a self-protection reaction of flushing all excess B12 from your body once those stores are filled to a certain limit. This means most doctors do not worry at all about toxicity or overdose, even when patients take injections and daily vitamins. A vitamin B12 shot overdose is extremely rare.
The only other side effects you might notice are darkened urine and tenderness or sensitivity at the site of the shot. The darkened urine just means your body is excreting the excess B12; the sensitivity just means your skin doesn't like getting poked with a needle, nothing more.
The positive effects of B12 shots are compelling. Most people who receive these shots experience improved emotional well being, increased energy, better memory retrieval, accelerated mental alertness and recovered nerve function. For people with memory problems, Celiac's disease, Crohn's disease, anemia or age-imposed gastric complications, B12 shots can be essential to optimal health. Because many people with these issues can not absorb dietary sources of B12 or oral supplements, the shot is a way to bypass stomach problems and get the much-needed B12 into the blood system and the muscle tissues.
There are many vital Vitamin B12 benefits. Vitamin B12 is responsible for proper nerve function, healthy red blood cells and the formation of DNA. Deficiencies are rare, but vegans, individuals with digestive disorders and people over the age of 50 may benefit from oral supplements or injections to maintain proper levels.
If you fear you might have a B12 deficiency, brush up on vitamin B12 deficiency symptoms.