Vitamin B12 & PCOS - A Vitamin You Don't Want to "B" Without
20% off Herbal Tea Bundle & Diva DeStress. Use Codes: TEA20 or DESTRESS20

A PCOS Vitamin You Don’t Want to “B” Without

by Amy Medling, founder of PCOS Diva

I used to think that taking a Centrum multivitamin would take care of all my body’s nutritional needs. Now I know better. Most over the counter supplements are not monitored for quality or content by an independent lab and frequently do not contain the ingredients advertised. At any rate, I would much rather get my vitamins from my produce section and farmer’s market than from a bottle, but as a woman with Polycystic Ovarian Syndrome (PCOS), sometimes food sources just are not enough.

There are certain vitamins that are commonly lacking from our diets and require supplements. Vitamin D, for example, gets a lot of press. You may not know about another common deficiency – a critical “B” vitamin – B12. Women with PCOS become depleted of B12 for many reasons with serious consequences such as fatigue, lethargy, weakness, memory loss, neurological and psychiatric problems and anemia. Frighteningly, many common diseases (such as Alzheimer’s Disease, cardiovascular disease, mental illness, autoimmune disease and more) have symptoms that mimic those of B12 depletion and are easily misdiagnosed.

What is B12?

According to Wikipedia, “B12 is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins. It is normally involved in the metabolism of every cell of the human body, especially affecting DNA synthesis and regulation, but also fatty acid synthesis and energy production. It is the largest and most structurally complicated vitamin.”

Who is low in B12?

Data from the Tufts University Framingham Offspring Study suggests that 40 percent of people between the ages of 26 and 83 have plasma B12 levels in the low normal range – a range at which many experience neurological symptoms. 9 percent had deficiency, and 16 percent exhibited “near deficiency.” Most surprising to the researchers was that low B12 levels were common in younger people.

Where do you get B12?

*Vegetarians and vegans take note!

B12 is only found in animal based food. Here are some of the top B12 containing foods.

  • Mollusks (clams, oysters, mussels
  • Beef liver
  • Salmon
  • Wild trout
  • Sirloin Beef
  • Yogurt
  • Milk
  • Pork
  • Eggs
  • Chicken

Vegetarians and vegans should understand that there are no plant sources of B12, and studies consistently show that up to 50% of long-term vegetarians and 80% of vegans are deficient in B12.

Symptoms of B12 deficiency:

I’ve highlighted some symptoms that overlap with typical PCOS symptoms.

  • Premature grey hair
  • Disturbed carbohydrate metabolism
  • Fatigue
  • Weakness
  • Dizziness
  • Weight loss
  • Constipation
  • Infertility
  • Vision problems
  • Loss of hearing and tinnitus
  • Numbness and tingling in the hands and feet
  • Alcoholism
  • Incontinence
  • Hyperpigmentation and hypopigmentation (dark and light patches in the skin)
  • Psoriasis and other skin problems
  • Insomnia
  • Irrational or chronic anger
  • Violent behavior
  • Lack of balance/abnormal gait
  • Any emotional disorder

B12 and infertility

“Vitamin B12 deficiency is associated with infertility,” says hematologist Michael Bennett, M.D. in Could it be B12? “Pregnancy may occur in the presence of B12 deficiency but may be associated with recurrent early fetal loss.” Luckily, supplementation can help. Doctors have reported successful pregnancies in once-infertile women following therapy for B12 deficiency. If you are going through fertility treatments, insist on a B12 test.

What causes B12 deficiency?

There are many causes of B12 deficiency ranging from poor diet, to medication side effects to other medical conditions (such as leaky gut and/or gut inflammation, low stomach acid, pernicious anemia, alcohol use, and exposure to nitrous oxide).

  • Metformin causes B12 deficiency – 

    When I was taking metformin, my doctor never told me that I could become B12 deficient and was never told to supplement. If you have PCOS and are taking metformin, talk to your doctor about supplementing with B12 and have your levels checked regularly. Bring your doctor the summaries of the studies associated below.

  • Oral contraceptives may cause B12 deficiency  – 

    The data regarding the effects of oral contraceptives on vitamin B12 serum levels are conflicting. Some studies have found reduced  levels in oral contraceptive users, but others have found no effect despite use of oral contraceptives for up to 6 months. When oral contraceptive use is stopped, normalization of vitamin B12 levels usually occurs. Again you can bring the study summaries to your doctor.  Most women are taking metformin and OC’s – a double whammy!

What tests can I take to know if I am low in B12?

  • B12: Normal values are 200 – 900 pg/mL (picograms per milliliter).
  • CBC (Complete Blood Count). This is actually a group of tests ordered routinely to screen for blood cell abnormalities. It measures cell types, quantities, and characteristics. With both B12 and folate deficiencies, the amount of hemoglobin and RBC count may be low, and the RBCs are abnormally large (macrocytic or megaloblastic), resulting in an anemia. White blood cells and platelets also may be decreased.
  • Methylmalonic Acid (MMA). This is sometimes ordered to help detect mild or early B12 deficiency. A normal serum sMMA level is .07 to .27 µmol/l. A normal urine uMMA level is .58 – 3.56 µmol/mmol
  • Homocysteine(HCY). This one is only occasionally ordered. Levels may be elevated in both B12 and folate deficiency. A normal serum HCY is 2.2 – 13.2 µmol/l

If MMA and homocysteine levels are increased and the vitamin B12 levelis mildly decreased, then an early or mild B12 deficiency may be present. This may indicate a decrease in available B12 at the tissue level. If only the homocysteine level is elevated, then the person


may have a folate deficiency. If both MMA and homocysteine levels are normal, then it is unlikely that there is a B12 deficiency.

Supplementing B12

The most commonly used form of supplemental B12 in the US is cyanocobalamin – that is what you will find in your Centrum vitamins. However, only two forms of B12 are active in the body – methylcobalamin and adenosylcobalamin. Cyanocobalamin must be converted in the body to either methyl or adenosyl cobalamin.  But if you supplement with methylcobalamin, your body can immediately use this active form of vitamin B12  which is available at most health food stores  in the US.  It can be supplemented in pill form, sublingual tablet, liquid, transdermal patch, nasal spray, and even lollipop.  I take the PCOS Diva Essentials Multivitamin every day.  I personally sourced it from the most reputable nutraceutical company I could find to ensure quality and consistent effectiveness.  It is specifically designed for women with PCOS and contains the critical B12 as methylcobalamin.

If your B12 is really low your doctor may prescribe injections. The standard protocol is 1000 micrograms daily for three days, then weekly for a month, then one injection per month indefinitely.

*Be sure that you chose a B12 supplement that is verified by a third party, independent lab or you cannot be certain that the quality or quantity you are consuming is accurate.  In some cases, uninspected supplements contain none of the nutrient advertised! For guidelines on how to choose a quality supplement, read, Choosing the Right Supplement for PCOS: Not All Supplements Are Created Equal.

Be a PCOS Diva!

Ask to have your B12 tested.  Most physicians do not routinely test B12. Even if you are within “normal” ranges you could be too low for you. People with B12 levels between 200 pg/mL and 350 pg/mL – levels considered “low-normal” in the U.S. In Japan and Europe, the lower limit for B12 is between 500-550 pg/mL.



Antony, AC. “Vegetarianism and Vitamin B-12 (cobalamin) Deficiency.” Am J Clin Nutr. U.S. National Library of Medicine, July 2003. Web.

Bennett, M. “Vitamin B12 Deficiency, Infertility and Recurrent Fetal Loss.” National Center for Biotechnology Information. J Reprod Med., Mar. 2001. Web. 25 Jan. 2016.

Berenson, AB, and M. Rahman. “Effect of Hormonal Contraceptives on Vitamin B12 Level and the Association of the Latter with Bone Mineral Density.” National Center for Biotechnology Information. Contraception., Nov. 2012. Web. 25 Jan. 2016.

Bissoli, L. “Effect of Vegetarian Diet on Homocysteine Levels.” Ann Nutr Metab. U.S. National Library of Medicine, 2002. Web.

Carmel R. Mild transcobalamin I (haptocorrin) deficiency and low serum cobalamin concentrations. Clin Chem 2003;49(8):1367-74

Gardyn J, Mittelman M, Zlotnik J, Sela BA, Cohen AM. Oral contraceptives can cause falsely low vitamin B(12) levels. Acta Haematol 2000;104(1):22-4.

Kos, E., and MJ Liszek. “Effect of Metformin Therapy on Vitamin D and Vitamin B₁₂ Levels in Patients with Type 2 Diabetes Mellitus.” National Center for Biotechnology Information. Endocr Pract., Mar.-Apr. 2012. Web. 25 Jan. 2016.

Kresser, C. “B12 Deficiency: A Silent Epidemic with Serious Consequences.” Chris Kresser. Chris Kresser, 06 May 2011. Web. 25 Jan. 2016.

Kumthekar, AA, HV Gidwani, and AB Kumthekar. “Metformin Associated B12 Deficiency.” National Center for Biotechnology Information. J Assoc Physicians India., Mar. 2012. Web. 25 Jan. 2016.

Lussana F, Zighetti ML, Bucciarelli P, Cugno M, Cattaneo M. Blood levels of homocysteine, folate, vitamin B6 and B12 in women using oral contraceptives compared to non-users. Thromb Res 2003;112(1-2):37-41.

McBride, Judy. “Read: Details in Agricultural Research Magazine. B12 Deficiency May Be More Widespread Than Thought.” United States Department of Agriculture Agricultural Research Service. United States Department of Agriculture Agricultural Research Service, 02 Aug. 2000. Web.

Nervo, M. “Vitamin B12 in Metformin-treated Diabetic Patients: A Cross-sectional Study in Brazil.” National Center for Biotechnology Information. Rev Assoc Med Bras., Jan.-Feb. 2011. Web. 25 Jan. 2016.

Pacholok, Sally M., and Jeffrey J. Stuart. Could It Be B12?: An Epidemic of Misdiagnoses. Sanger, CA: Quill Driver /Word Dancer, 2005. Print.

Riedel B, Nexo E, et al. Effects of oral contraceptives and hormone replacement therapy on cobalamin status. J Inherit Metab Dis 2003;23(supl):127

Rosenthal HL, Wilbois RP. Influence of oral contraceptive agents on vitamin B12 absorption and plasma level. Fed Proc 1975:34:905.

Shojania AM, Wylie B. The effect of oral contraceptives on vitamin B12 metabolism. Am J Obstet Gynecol 1979;135(1):129-34.

Sutterlin MW, Bussen SS, Rieger L, Dietl J, Steck T. Serum folate and Vitamin B12 levels in women using modern oral contraceptives (OC) containing 20 microg ethinyl estradiol. Eur J Obstet Gynecol Reprod Biol 2003;107(1):57-61.

Vakur Bor, M. Do we have any good reason to suggest restricting the use of oral contraceptives in women with pre-existing vitamin B12 deficiency? Eur J Obstet Gyn Repr Biol 2004;115:240-241.

Polycystic Ovarian Syndrome Treatment in USA, PCOS Medication in USA, PCOS Diet And Weight Loss in USA, PCOS Hormonal Imbalance Supplement in USA, PCOS Infertility And Pregnancy in USA

Last Post

Without ~ Rethinking Fertility

Next Post

Awaken Your Good Health Goddess

Polycystic Ovarian Syndrome Treatment in USA, PCOS Medication in USA, PCOS Diet And Weight Loss in USA, PCOS Hormonal Imbalance Supplement in USA, PCOS Infertility And Pregnancy in USA

Share Your Thoughts

Your email address will not be published. Required fields are marked *

  1. This is a wonderful article! Thanks for the heads-up! I’m on both Metformin and oral contraceptives, as many women with PCOS are. I know I’ve experienced many of those symptoms listed above! I’m definitely going to look into upping my intake of B12!

    Thank you!

  2. Phew! Even without taking Met I ‘ve had some of those symptoms in the past – for so many years in fact. Thanks for sharing this and eapecially for breaking it down.

  3. This is a great article, thank you! Thankfully, my Dr. over the last year had been giving me monthly B12 shots because I am on Metformin. I just recently purchased the B12 supplements you have pictured in this article so hopefully I’m on the right track.

  4. One thing to keep in mind… even with all our fancy tests, you do not always know you are B12 deficient… I was on the other side where my blood tests showed I had tons of B12— over 1600 in Active B12 but I am MTHFR A1298 Double Mutated, which means I have not been getting any B12 my entire life… as this mutation stops it. As soon as I started taking methyl B12… many of my major symptoms let up but I still have a long way to go in healing a lifetime of problems. Good luck to all!

  5. Definitely going to start supplementing with B12. I was recently diagnosed with PCOS and Vitamin D deficiency (which I also understand goes hand in hand with PCOS). I have had a number of these symptoms, including the tingling in hands, etc and have had blurrier vision than normal (I wear glasses regularly, but have noticed a decline in visual acuity lately). I am so glad to see this and hope the supplementation helps with these symptoms. Thank you for sharing!

  6. This is a helpful article. I do wish these articles didn’t single out vegetarians / vegans though, especially since B12 deficiency was first discovered in meat eaters, plus 99% of deficiency is seen in meat eaters.

  7. fermented foods like pickles, sauerkraut, yogurt, tempeh, miso and kimchi are all great sources of B12 as well as probiotics