Vitamin B12 deficiency is treatable, and the right treatment depends on why your levels are low. For some people that’s a daily pill, and for others it’s a series of shots. Either way, the goal is the same: raise your B12 and protect your nerves and blood.

The short version

  • Treatment depends on the cause. Low intake is treated with supplements or fortified foods. Trouble absorbing B12 usually needs shots or very high doses by mouth, according to the NIH.
  • Pernicious anemia is an autoimmune condition that stops your body from absorbing B12. It needs treatment for life.
  • Pills can work. A review of the research found that 1,000 mcg of oral B12 a day replaced B12 levels in people with pernicious anemia and is an effective alternative to injections.
  • Don’t treat yourself with folic acid. Large amounts can fix the anemia of B12 deficiency while nerve damage continues.
  • If you’re pregnant or breastfeeding, your needs rise, and your baby depends on your B12. Tell your provider if you eat little or no animal food.

How it’s confirmed

A blood test checks your B12 level. Your provider may also check homocysteine, which builds up when B12, folate, or B6 is low, according to MedlinePlus, and methylmalonic acid (MMA), a substance that’s high when B12 is low. A blood count looks for the large red blood cells that B12 deficiency causes. See Vitamin B12 Deficiency for symptoms and risk factors.

Treatment depends on the cause

Cause Usual approach
Not enough B12 in your diet, such as a vegan or vegetarian diet B12 supplements or fortified foods
Trouble absorbing B12 from food, such as pernicious anemia, stomach or intestinal surgery, Crohn’s disease, or celiac disease B12 shots, or very high doses by mouth
A medicine that lowers B12, such as metformin or long-term acid reducers Your provider may add a B12 supplement rather than stop a medicine you need

The NIH describes these approaches. Your provider will choose the one that fits your cause and your symptoms.

The treatment options

Pills and fortified foods. If your diet is the cause, B12 supplements or foods fortified with B12 usually fix it, according to the NIH. Supplements come as tablets, capsules, liquids, and nasal forms. The most common form is cyanocobalamin, and research hasn’t shown that one form works better than another.

High-dose pills. For people who can’t absorb B12 well, very high doses by mouth may work. A 2016 review in PubMed Central found that 1,000 mcg of oral B12 a day was adequate to replace B12 in people with pernicious anemia, and concluded oral B12 is an effective alternative to injections. The review also noted that many people with pernicious anemia are treated with lifelong injections, and that dosing and monitoring need to be set by a provider. See the review.

Shots. Injections go around the digestive system, so they work even when absorption is poor. The NIH says people with pernicious anemia must receive B12 injections for life, with injections often given weekly for a few weeks and then monthly or every few months.

Nasal gel. A prescription nasal gel is another option for some people.

B12 hasn’t been shown to cause harm, even at high doses, so no upper limit has been set. Still, check with your provider before taking a high-dose supplement, because the amount you need depends on your cause.

Don’t treat yourself with folic acid

Large amounts of folic acid can correct the anemia caused by low B12 while the nerve damage keeps going, according to the NIH. That can hide the real problem and delay treatment. If you’re tired and think you may have anemia, ask for a blood test first.

Follow-up

Your provider will usually recheck your B12 level and blood count to make sure treatment is working. Ask when your next test is due, and don’t stop treatment because you feel better, especially if the cause is pernicious anemia or an absorption problem.

If you’re pregnant or breastfeeding

You need 2.6 mcg of B12 a day in pregnancy and 2.8 mcg while breastfeeding, according to the NIH. Your baby depends on your supply. If you eat little or no animal food, ask your provider about B12 early. Breastfed babies of women who eat no animal products may get very little B12, which can put them at risk of nerve damage, according to the CDC. See Prenatal Vitamins While Breastfeeding and Vegan and Vegetarian Prenatal Vitamins.

What to do now

  • If you have symptoms such as numb or tingling hands and feet, balance problems, memory trouble, or constant tiredness, ask for a B12 blood test.
  • Don’t start high-dose folic acid to treat anemia on your own.
  • If you’re prescribed shots or high-dose pills, ask how long you’ll need them and when to recheck.
  • If you eat no animal foods, make sure your prenatal or another supplement includes B12.

Related reading

Sources

Updated November 2026. This article is for general information and is not a substitute for advice from your health care provider.