Is vitamin B12 one of the nutrients or supplements you’ve heard discussed for PCOS? This nutrient is linked to PCOS and may be something you may need more of, especially if you take certain medications. 

As a registered dietitian specializing in PCOS, I’m going to break things down for you. This blog post will dive into the link between vitamin B12 and PCOS, who is at risk for a deficiency, symptoms of a deficiency, and then vitamin B12 supplement information. 

This post may contain affiliate links. This means that if you click on a link and make a purchase, I may receive a small commission at no additional cost to you. 

What Is Vitamin B12?

Vitamin B12 is a water-soluble vitamin. It’s naturally present in some foods, added to some foods, or available as a supplement.

Vitamin B12 plays an important role in the development of red blood cells, DNA synthesis, and central nervous system function. 

When it comes to fertility, vitamin B12 also plays a key role in normal ovulation and pregnancy rates. 

How Much Vitamin B12 Do You Need?

The Recommended Dietary Allowance (RDA) for vitamin B12 is 2.4 micrograms for adult females. For those who are pregnant or breastfeeding, the RDA increases to 2.6 mcg and 2.8 mcg. 

Food Sources of Vitamin B12

Most good food sources of vitamin B12 are animal products such as meats and dairy products. Some plant-based foods are fortified with vitamin B12, which can make them good sources of this nutrient too. 

Good Sources of Vitamin B12: 

• Shellfish (oysters, clams, crab)
• Fish (trout, salmon, haddock, tuna)
• Beef (including beef liver)
• Dairy (milk, yogurt, cheese)
• Eggs
• Fortified cereals
• Fortified plant milks 
• Nutritional yeast 

Considering most foods that have high amounts of vitamin B12 are animal-based, those who follow a vegetarian or vegan diet may be particularly vulnerable to a B12 deficiency.

What’s The Link Between Vitamin B12 and PCOS?

While the exact relationship isn’t super clear, there are some things we do know about the link between vitamin B12 and PCOS. 

We do know that among people with PCOS, if obesity or insulin resistance is also present, there’s a higher chance of having low vitamin B12 levels (1). We also know that there are several prescription medications commonly prescribed for PCOS that can cause a vitamin B12 deficiency. 

Metformin, a popular insulin sensitizer drug that’s commonly prescribed with PCOS, is known to reduce B12 levels (2). Hormonal birth control and common heartburn medications, such as proton pump inhibitors (PPIs) or H2 blockers, are also known to lower vitamin B12 levels (3, 4).

Additionally, low vitamin B12 levels can cause high homocysteine levels, which can trigger oxidative stress and chronic inflammation. This is interesting too since chronic inflammation has emerged as part of the pathogenesis of PCOS. 

Essentially, some women with PCOS may be at a higher risk of developing a vitamin B12 deficiency. In my experience, vitamin B12 deficiencies can commonly go undetected. Let’s take a look at some of the symptoms of a deficiency. 

Symptoms of Vitamin B12 Deficiency

A deficiency in vitamin B12 can manifest in several different ways. Thankfully, your doctor can run a simple blood test to screen for vitamin B12 deficiency. Talk to your doctor about this nutrient if you think you’re at risk. 

Vitamin B12 Deficiency Symptoms:

• Fatigue
• Anemia, including pernicious anemia
• Neurological changes
• Cognitive impairment and dementia
• Pins and needles tingling in hands or feet
• Hair loss
• Glossitis of the tongue
• Pale skin

Since the body can store ample amounts of vitamin B12, it may take years for symptoms of a vitamin B12 deficiency to become apparent.

Vitamin B12 Supplements

Your doctor can screen you for a vitamin B12 deficiency with a simple blood test. If you’re deficient, they may recommend vitamin B12 supplements. Vitamin B12 supplements are available over-the-counter in several forms, such as tablet, sublingual (under the tongue), or liquid; it’s also available as a monthly injection through a healthcare provider. 

Dietary supplements are available in a variety of forms of vitamin B12. Cyanocobalamin is probably the most common form of vitamin B12 found in supplements. Once ingested, cyanocobalamin needs to be converted to a methylated form of vitamin B12 so the body can actually utilize it. For some people, especially those with a MTHFR gene mutation, choosing a methylated vitamin B12 supplement may be advantageous. 

Since dietary supplements aren’t well-regulated by the US Food & Drug Administration (FDA), I highly recommend choosing supplements from brands that undergo voluntary third-party testing to ensure quality and purity. 

Vitamin B12 is commonly added to many multivitamins and prenatal vitamin supplements. It’s important to look for overlap between supplements.

This vitamin B12 supplement and this one are two of my favorite B12 recommendations if you need to supplement.

Always talk to your healthcare provider before starting any dietary supplements.

The Bottom Line

Vitamin B12 is a water soluble vitamin naturally found in many animal-based foods. It’s also added to many foods during a fortification process. 

Vitamin B12 and PCOS appear to be linked. Women with PCOS, especially those with a high BMI or insulin resistance, tend to have lower levels of vitamin B12. 

Additionally, common medications prescribed for PCOS, such as Metformin and birth control, can cause low B12 levels. 

Low levels of vitamin B12 can cause hair loss, anemia, fatigue, neurological changes, pins and needles, pale skin, glossitis, and even dementia. 

If you or your doctor suspect a vitamin B12 deficiency, a simple blood test can screen you for this deficiency. 

Vitamin B12 supplements may be necessary to correct low levels of vitamin B12. Always talk to your healthcare provider before taking any new dietary supplements.

For more information on the most popular PCOS supplements and how to decide which ones are the best ones to consider for yourself, check out The PCOS Lab & Supplement Guides!

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Disclaimer: this is for informational purposes only. It does not substitute for or replace professional medical advice for polycystic ovary syndrome (PCOS) or any other medical condition. Always discuss your healthcare needs and dietary supplements with your healthcare professional.