Vitamin B12 Side Effects

Vitamin B12, also called cobalamin, is a water-soluble vitamin that has a key role in the normal functioning of the brain and nervous system, and the formation of red blood cells. Though it’s considered safe, some are convinced it has potentially dangerous health effects.

What Is Vitamin B12?

Vitamin B12, also known as  cobalamin, is the largest and most complex of all the B-vitamins. Vitamin B12 is used for general food fortification and dietary supplement applications. It is suitable for both solid and liquid vitamin/mineral formulations.

Possible Side Effects of Vitamin B12

Although Vitamin B12 generally regarded as a very safe and effective supplement, there can be some minor side effects. The side effects may:

  • Abdominal or stomach pain
  • bleeding from the gums or nose
  • blue lips and fingernails
  • chest pain
  • cough
  • coughing that sometimes produces a pink frothy sputum
  • decreased urine output
  • difficult, fast, noisy breathing, sometimes with wheezing
  • difficulty with swallowing
  • dilated neck veins
  • dizziness
  • extreme fatigue
  • eye pain
  • fast heartbeat
  • headache
  • hives, itching, or skin rash
  • increased sweating
  • irregular breathing
  • irregular heartbeat
  • pale skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • ringing in the ears
  • swelling of the face, fingers, feet, or lower legs
  • tightness in the chest
  • unusual tiredness or weakness
  • weight gain

GRAS Affirmation: Yes

Generally recognized as safe (GRAS) is an American Food and Drug Administration (FDA) designation that a chemical or substance added to food is considered safe by experts, and so is exempted from the usual Federal Food, Drug, and Cosmetic Act (FFDCA) food additive tolerance requirements. Vitamin B12 is considered safe.

Suggested Dosage


Special Populations Precaution

There is a lot of concern about diet and nutrition for these population, like Newborns, children, pregnant, sensitive to Vitamin B12 populations. Better consult to your doctor if you would like to intake Vitamin B12.


Related Research

1. The Effect of Vitamin B12 Infusion on Prevention of Nitrous Oxide-induced Homocysteine Increase: A Double-blind Randomized Controlled Trial. [Oman Med J. 2014 May] Author: Kiasari AZ, Firouzian A, Baradari AG, Nia HS, Kiasari SH.

2. Vitamin B12 deficiency due to nitrous oxide use: unrecognized cause of combined spinal cord degeneration. [Rev Med Interne. 2014 May] Author: Chaugny C, Simon J, Collin-Masson H, De Beauchêne M, Cabral D, Fagniez O, Veyssier-Belot C.

3. Vitamin B12 and homocysteine status during pregnancy in the metformin in gestational diabetes trial: responses to maternal metformin compared with insulin treatment. [Diabetes Obes Metab. 2013 Jul] Author: Gatford KL, Houda CM, Lu ZX, Coat S, Baghurst PA, Owens JA, Sikaris K, Rowan JA, Hague WM.

4. Cognitive impairment and vitamin B12: a review. [Int Psychogeriatr. 2012 Apr] Author: Moore E, Mander A, Ames D, Carne R, Sanders K, Watters D.

5. Oral vitamin B12 replacement: an effective treatment for vitamin B12 deficiency after total gastrectomy in gastric cancer patients. [Ann Surg Oncol. 2011 Dec] Author: Kim HI, Hyung WJ, Song KJ, Choi SH, Kim CB, Noh SH.

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