B12 supplements have no known major risks and is considered very safe. But you still need to take the proper dose. These are guidelines of the correct dosage that you should take on a daily basis. But if taken in excessive amounts then it is possible that you will experience adverse side effects. However, these side effects will expire soon as the excess amounts of vitamin B12 is flushed out of your body. Even then, it is important for you to know about vitamin B12 side effects so that you will be more careful when taking your daily dose.
Most of these side effects are experienced by those who are using vitamin B12 injectables. But some of them are also true for those who are taking other forms of vitamin B12, including sublingual vitamin b12. The side effects can either be mild or severe. For mild side effects, you will experience swelling and pain on the skin where the vitamin is injected. You may also feel nauseous, accompanied with vomiting sensations. It’s also possible to get headaches (mild or severe), rashes, diarrhea and joint pains.
But it’s the severe side effects that you need to be most careful with. You may suffer heart palpitation causing you to lose your breath. Feeling numbness all over your body is another. Other serious side effects may include difficulty in swallowing, getting tired easily even with light work, urinating frequently especially at night, muscle pains in the legs, muscle cramps, tight chest sensation and sudden weight gain.
Side effects can also be of a psychological nature. Taking excess B12 can lead to anxiety and panic attacks. You just have to control your nerves when this happens, because this will disappear in a few hours, after the excess B12 is flushed out of your system.
If you have a history of Leber’s disease, then there is a rare side effect that you need to be aware of. Before taking vitamin B12 supplements, such people need to consult their doctors first. Leber’s disease is a hereditary condition that causes the atrophy of the optic nerve. Large doses of vitamin B12 for such persons may result in the onset of this disease, or it may cause the rapid deterioration of their optic nerve.
People who are allergic to cobalt and cobalamin should also avoid taking B12 supplements. They should endeavor to get their daily requirements of B12 from natural foods such as beef liver, fish, oysters, yogurt, milk, etc.