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Feeling Fatigued? A Vitamin B12 Deficiency May Be the Culprit

Get your energy back.


It’s normal to feel tired sometimes. Managing work, family, and social commitments can be exhausting. But when day-to-day tiredness turns into debilitating fatigue, it’s time to make a change. If you’re missing out on plans and events because you feel foggy, and no amount of sleep makes you feel rested again, you may have a vitamin B12 deficiency. Read more about the symptoms, diagnosis, and remedies for a B12 deficiency and see how adjusting your levels could change your life for the better.

What is vitamin B12?

“B12 plays a vital role in metabolizing fat, protein, and carbs into energy,” says Fred Pescatore, MD. And it works in tandem with the B vitamin folate to make healthy red blood cells that transport energizing oxygen through the body, so it makes sense that when you’re low on this vitamin, you’re low on power. According to WebMD, normal B12 levels are between 190 and 950 picograms per milliliter, but your doctor may do extra testing if your levels are between 200 and 300, since those are considered to be borderline low levels.

Who is at risk for B12 deficiency?

B12 deficiencies are common in women over 50, suggests a Tufts University study. But some women have genetic variations that impede the conversion of B12 into its active form; plus, drop-offs in stomach acid that occur after age 50 can impair B12 absorption. So even if you supplement, it may not lift B12 levels. The result? Fatigue, fog, and more. Complicating matters: Even women without the genetic glitch can fall short in B12 if they adopt a strict plant-based diet. In fact, research in the European Journal of Clinical Nutrition finds that plant-based plans raise the risk of B12 deficiency.

How do I know if I have a B12 deficiency?

Blood tests can measure B12. But the tests can produce false results, and as Dr. Pescatore notes, levels many doctors consider normal can produce symptoms. His advice: Ask for tests that measure homocysteine and methylmalonic acid, substances that rise in the blood when B12 is low. If either is low, the steps below can help.

How can I raise my B12 levels?

Taking supplements can lift energy in four weeks. Dr. Pescatore’s advice: Each day, take 2,000 mcg. of sublingual methylcobalamin, which delivers B12 via blood vessels under the tongue, and 1,000 mcg. of methylfolate, a form of folate that’s readily used by the body. Try Solgar Sublingual Methylcobalamin (Buy from Amazon, $7.49) and Klaire Labs L-Methylfolate (Buy from Amazon, $22.49). Diet changes can also help. Dr. Pescatore advises scaling back on sugar, which depletes B12. Also smart: Enjoy foods rich in both B12 and folate, like beef, fish, shellfish, and eggs.

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This article originally appeared in our print magazine, First For Women.

This content is not a substitute for professional medical advice or diagnosis. Always consult your physician before pursuing any treatment plan.

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