3 Major Roles of Vitamin D for PCOS

Vitamin D plays an important role in the health and fertility for women with polycystic ovary syndrome (PCOS). Despite the importance, research shows that 67-85% of women with PCOS are deficient in vitamin D. (1)

A deficiency of Vitamin D not only causes poor bone mineralization but also has been implicated in numerous chronic diseases including diabetes, heart disease, poor immunity, various cancers, multiple sclerosis, rheumatoid arthritis, and high blood pressure.

Vitamin D is the only vitamin that’s also a hormone. As a hormone, there are vitamin D receptors on the cells and tissues in our bodies. Vitamin D receptors have been found on oocytes as well as immune cells. A deficiency of vitamin D can affect all the cells in our bodies causing them to not function optimally. Here are just a few roles of vitamin D.

Roles of Vitamin D

3 Major Roles of Vitamin D for PCOS

While vitamin D is important for numerous health benefits and is needed for optimal functioning, here are 3 major roles of vitamin D specifically for women with PCOS.

Vitamin D Improves Fertility

If you’re trying to conceive, make sure your vitamin D levels are in the optimal ranges or consider adding a vitamin D supplement (see chart below). The reason? Vitamin D receptors have now been identified in almost every tissue and cell in the human body and vitamin D has been found to be directly involved in follicle egg maturation and development.

Below are studies demonstrating the effectiveness of vitamin D supplementation for improving fertility in women with PCOS.

Data from more than 1,000 participants: “Vitamin D deficiency in PCOS women was associated with a reduced likelihood of these women becoming pregnant and delivering babies, regardless of BMI, race, age, markers of metabolic functioning, or fertility treatment”

Infertile PCOS women had a higher number of dominant follicles and improvements in menstrual regularity when taking metformin + Vitamin D (100,000 IU/month for 6 months) compared with metformin alone. (2)

Infertile women with PCOS who underwent clomid stimulation had more mature follicles (57%) and were more likely to get pregnant (26.4%) with higher vitamin D levels. (3)

Vitamin D supplementation lowered abnormally elevated serum AMH levels in vitamin D deficient women with PCOS. (4)

Vitamin D Lowers Androgens

Vitamin D has been associated with reducing androgen levels in women with PCOS. A review of six clinical trials with 183 women with PCOS revealed that vitamin D supplementation significantly reduced total testosterone levels (5).

Another study also found significant reduction in androgens in PCOS women. Both total testosterone and androgens levels were reduced (by 12% and 17%) after three months of supplementing with vitamin D 50,000 IU daily along with calcium. Patient blood pressure profiles were also improved. (6)

Vitamin D Lowers Inflammation

PCOS is a state of low-grade inflammation that may stem from insulin resistance. Compared to women without PCOS of similar weight and ages, women with PCOS have higher levels of the inflammatory marker c-reactive protein (CRP).

A study published in Dermatoendocrinology showed that supplementing with vitamin D3 reduced markers of inflammation in individuals with inflammatory conditions.

A study published in Nutrients showed that vitamin D supplementation at a dosage of 4,000

vitamin D for PCOS

 IU/day for 12 weeks to insulin-resistant women with PCOS had beneficial effects on lowering total testosterone as well as inflammatory markers (hs-CRP levels) and antioxidant levels, compared with those who supplemented with 1,000 IU/day of vitamin D and placebo groups. (7)

A previous randomized double-blind placebo-controlled trial showed calcium plus vitamin D (50,000 IU vitamin D weekly) for 8 weeks among vitamin D-deficient women with PCOS had beneficial effects on inflammatory and biomarkers of oxidative stress compared to a placebo. (8)

Optimal Vitamin D Levels

Blood levels of Vitamin D can be measured by checking serum 25-Hydroxyvitamin D [25(OH)D] concentrations and should be a part of an annual physical examination for all individuals.

Serum 25-Hydroxyvitamin D [25(OH)D] Concentrations*  (9)

<30 <12  

Associated with vitamin D deficiency, leading to rickets
in infants and children and osteomalacia in adults


30 to <50 12 to <20  

Generally considered inadequate for bone and overall health
in healthy individuals


≥50 ≥20  

Generally considered adequate for bone and overall health
in healthy individuals


>125 >50  

Emerging evidence links potential adverse effects to such
high levels, particularly >150 nmol/L (>60 ng/mL)


per liter (nmol/L) and nanograms per milliliter (ng/mL).
** 1 nmol/L = 0.4 ng/mL

Are You Getting Enough Vitamin D?

The optimal amount of vitamin D for women with PCOS is unknown. Many researchers believe the current amount for Vitamin D is set too low at 600 International Units (IU) daily and should be increased. Women who are deficient in vitamin D or have suboptimal levels, will need higher amounts of vitamin D than the RDA, typically 2,000 IU to 5,000 IU daily. The tolerable upper limit (UL) for Vitamin D is 2,000 IU per day, however, no adverse effects have been found up to 10,000 IU per day.

Few foods contain Vitamin D other than milk fortified with Vitamin D, eggs, liver, cereals with vitamin D added, and fatty fish (see below).

Skin exposure to the sun provides as much as 80 to 90% of the body’s vitamin D. Just being outside in bright daylight for 15 minutes can provide approximately 10,000 IU! Using sunscreen and being indoors can prevent the absorption of vitamin D as can living in northern locations that don’t get direct sunlight year-round.

The elderly and dark skinned people may be at risk for a Vitamin D deficiency as melanin blocks the conversion of active Vitamin D in the skin.

Vitamin D, because it is a fat-soluble vitamin and may not be as bioavailable in high amounts of fat tissue. In fact, fat people may have as much as a 57% reduction in serum Vitamin D levels than thin individuals as bioavailability is reduced both by skin synthesis and gastrointestinal absorption.

Food Sources of Vitamin D

The following are some food sources of Vitamin D. Again, you should be getting at least 600 IU per day. If you find you are not consuming enough Vitamin D consider taking a Vitamin D supplement.

Food Sources of Vitamin D IUs per serving* Percent DV**
Cod liver oil, 1 tablespoon 1,360 340
Swordfish, cooked, 3 ounces 566 142
Salmon (sockeye), cooked, 3 ounces 447 112
Tuna fish, canned in water, drained, 3 ounces 154 39
Orange juice fortified with vitamin D, 1 cup (check product labels, as amount of added vitamin D varies) 137 34
Milk, nonfat, reduced fat, and whole, vitamin D-fortified, 1 cup 115-124 29-31
Yogurt, fortified with 20% of the DV for vitamin D, 6 ounces (more heavily fortified yogurts provide more of the DV) 80 20
Margarine, fortified, 1 tablespoon 60 15
Sardines, canned in oil, drained, 2 sardines 46 12
Liver, beef, cooked, 3 ounces 42 11
Egg, 1 large (vitamin D is found in yolk) 41 10
Ready-to-eat cereal, fortified with 10% of the DV for vitamin D, 0.75-1 cup (more heavily fortified cereals might provide more of the DV) 40 10
Cheese, Swiss, 1 ounce 6 2

* IUs = International Units. (10)


  1. Thomson RL, Spedding S, Buckley JDVitamin D in the aetiology and management of polycystic ovary syndrome. Clin Endocrinol (Oxf). 2012 Sep; 77(3):343-50.
  2. Rashidi B et al. The effects of calcium-vitamin D and metformin on polycystic ovary syndrome: a pilot study.Taiwanese J Obstetrics & Gynecology. 2009;48:142–147.
  3. Ott J et al. Parameters for calcium metabolism in women with PCOS who undergo CCN stimulation: A prospective cohort study. European J Endocrinol. 2012;166(5):897-902.
  4. Irani M. Role of vitamin D in ovarian physiology and its implication in reproduction: a systematic review. Fertil Steril. 2014 Aug;102(2):460-468.e3.
  5. Azadi-Yazdi M1, Nadjarzadeh A1, Khosravi-Boroujeni H. The Effect of Vitamin D Supplementation on the Androgenic Profile in Patients with Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis of Clinical Trials. Horm Metab Res. 2017 Mar;49(3):174-179.
  6. Pal L, Berry A, Coraluzzi L, Kustan E, Danton C, Shaw J, Taylor H Therapeutic Implications of vitamin D and calcium in overweight women with polycystic ovary syndrome.. Gynecol Endocrinol. 2012;28:965–968.
  7. Mehri Jamilian,Fatemeh Foroozanfard, Elham Rahman. Effect of Two Different Doses of Vitamin D Supplementation on Metabolic Profiles of Insulin-Resistant Patients with Polycystic Ovary Syndrome. Nutrients. 2017 Dec; 9(12): 1280.
  8. Calcium plus vitamin D supplementation influences biomarkers of inflammation and oxidative stress in overweight and vitamin D-deficient women with polycystic ovary syndrome: a randomized double-blind placebo-controlled clinical trial.
  9. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010.
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Comments (9)
  • Grace

    March 4, 2017 at 3:23 pm

    Is it safe to take a 2,000 IU Vitamin D supplement along with the Nordic Naturals Pro-Omega-D, which has 1,000 IU of Vitamin D?

  • Angela Grassi

    March 6, 2017 at 9:37 am

    yes you can!

  • Enxhi

    February 14, 2018 at 1:58 pm

    Entonces, si sufres PCOS, sería mucho más aconsejable utilizar un tratamiento PCOS natural debido a que no tienen efectos secundarios y son menos costosos que los medicamentos regulares y lo más importante es que realmente CURE tu condición y no solo enmascarar los síntomas. Los tratamientos naturales PCOS han existido durante mucho tiempo y son ampliamente utilizados por muchas mujeres. Si está buscando una alternativa efectiva al costoso tratamiento farmacéutico, ya es hora de que considere algunos de los tratamientos naturales de PCOS para contrarrestar los síntomas que su afección ha adquirido y que realmente curen la causa y qué medicamentos no lo hacen. Modificación de la dieta y ejercicio: Una de las mejores formas de contrarrestar los síntomas que compró PCOS es una dieta adecuada y un buen ejercicio.

  • Jessica

    June 4, 2018 at 2:55 pm

    I’m 29 with PCOS. What’s the best IU for vitamin D to use? And can I use with melatonin and iron?

  • Angela Grassi

    June 11, 2018 at 4:32 pm

    Every woman is different so the amount to take will depend on your blood levels. Yes, it is fine to take vitamin D along with melatonin and iron.

  • Kimberly Frith

    March 14, 2019 at 9:33 pm

    I have pcos. Im
    49yrs old have a concern with thinning hair

  • Angela Grassi

    March 25, 2019 at 12:41 pm

    Hi Kimberly, did you see this post we have about hair loss? https://www.pcosnutrition.com/hair-loss/

  • Amara

    August 10, 2019 at 8:41 pm

    Is Vitamin D3 supplement of 5,000 IU okay for a young 21 year old woman with PCOS????

    I’m mainly taking it because I heard that vitamin d3 is great for people with severe dry skin and have heard gret reviews. But now hearing that vitamin d is also food for women with high androgenic PCOS, I’m happy. So, is that dose of only 5000 enough to help with insulin resistance and hormonal imbalance? Is it low or just as enough as 50,000 IU because this dose sounds really high.

  • Angela Grassi

    August 12, 2019 at 4:55 pm

    It depends on your vitamin D levels. if your vitamin D is really low you may need 5,000 IU per day. Vitamin D may help with insulin resistance but research still inconclusive.

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