What are the negative effects of B12?

High doses of vitamin B-12, such as those used to treat a deficiency, might cause:
  • Headache.
  • Nausea and vomiting.
  • Diarrhea.
  • Fatigue or weakness.
  • Tingling sensation in hands and feet.

Takedown request   |   View complete answer on mayoclinic.org

What damage can vitamin B12 do?

A lack of vitamin B12 can cause neurological problems, which affect your nervous system, such as: vision problems. memory loss. pins and needles (paraesthesia)

Takedown request   |   View complete answer on nhs.uk

Who should not take B12 supplements?

Who should not take VITAMIN B-12?
  • low amount of potassium in the blood.
  • Leber's hereditary optic atrophy.
  • inflammation of the stomach called atrophic gastritis.
  • past history of complete removal of stomach.

Takedown request   |   View complete answer on webmd.com

Can taking B12 everyday hurt you?

Is taking high doses of B12 helpful or harmful? Since B12 is a water-soluble vitamin, it's generally considered safe, even at high doses. No Tolerable Upper Intake Level (UL) has been established for B12, due to its low level of toxicity.

Takedown request   |   View complete answer on healthline.com

What does low B12 feel like?

extreme tiredness (fatigue) lack of energy (lethargy) breathlessness. feeling faint.

Takedown request   |   View complete answer on nhs.uk

Dangers of vitamin B12 deficiency

20 related questions found

What are the symptoms of low B12?

Key points about vitamin B12 deficiency anemia

Without enough oxygen, your body can't work as well. Symptoms include weak muscles, numbness, trouble walking, nausea, weight loss, irritability, fatigue, and increased heart rate.

Takedown request   |   View complete answer on hopkinsmedicine.org

What to avoid when taking B12?

Other medications can also interfere with your uptake of vitamin B12, possibly raising your risk for deficiency. These medications include antacids and peptic ulcer medications, cholesterol-lowering drugs, antiseizure medications, chemotherapy medications, the diabetes treatment glucophage (Metformin) and others.

Takedown request   |   View complete answer on sharecare.com

Does B12 interfere with any medications?

Antibiotics, Tetracycline: Vitamin B12 should not be taken at the same time as tetracycline because it interferes with the absorption and effectiveness of this medication. Vitamin B12 should be taken at different times of the day from tetracycline.

Takedown request   |   View complete answer on stlukes-stl.com

Does B12 supplement raise blood pressure?

The lowering effects of vitamin B12 together with folic acid on blood pressure have been reported in intervention study in adults. However, no study has reported the association of vitamin B12 by itself with systolic or diastolic blood pressure in children or in adults.

Takedown request   |   View complete answer on academic.oup.com

Can I take B12 indefinitely?

Your doctor will probably check your blood every now and then to make sure your B12 levels are normal. If you have pernicious anemia or another condition that doesn't go away, you may need shots or supplements forever. Your doctor will help you find the right plan to stay healthy.

Takedown request   |   View complete answer on webmd.com

How much B12 should a woman take daily?

Most women get the recommended daily amount — 2.4 micrograms (mcg) for most adults, 2.6 mcg for pregnant women, and 2.8 mcg for women who are breastfeeding — in their diets.

Takedown request   |   View complete answer on health.harvard.edu