Join the FREE 30-Day PCOS Diet Challenge
Home / Blog / PCOS Supplements / Vitamin D For PCOS: Why You Need It, Dosage, & Best Brands

Vitamin D For PCOS: Why You Need It, Dosage, & Best Brands

Kym Campbell

By Kym Campbell, BSc. | Updated March 18th, 2024

Comments (0)

There are hundreds of small ways to better manage a PCOS diagnosis.

Collectively, these small interventions can be transformative for your health and fertility. I get to witness this daily through my free 30-Day PCOS Diet Challenge.

The right diet is essential for any woman with PCOS. But certain supplements can help too. Here are three reasons to consider vitamin D for PCOS along with guidance on dosage and brands.

1. Vitamin D Treats The Underlying Mechanisms

Hyperandrogenism, inflammation, and oxidative damage play key roles in PCOS. Along with insulin resistance, and a poor diet, these are the underlying mechanisms that cause all PCOS symptoms [1-7].

Meta-analyses show that vitamin D supplements given to women with PCOS:

  • Improve hormones, inflammation, and oxidative stress [8].
  • Reduce insulin resistance and hyperandrogenism [9-11].
  • Improve lipid metabolism and triglycerides [9, 11-13].

What this means in practical terms is all very positive. Just like a PCOS diet, vitamin D supplements can reduce the strength of your current symptoms. They can also improve your long-term prognosis.

If you’ve taken part in my free 30-Day PCOS Diet Challenge and you’re now considering supplements, then vitamin D should be on your list.

2. It’s Important For Fertility

Vitamin D supplementation may also be helpful for fertility.

Anti-Müllerian hormone (AMH) is an ovarian biomarker that indicates the severity of ovarian dysfunction. It’s often elevated in women with PCOS who don’t get regular periods.

Studies show that vitamin D decreases AMH levels in anovulatory women with PCOS [14]. Evidence suggests that supplementation improves the development of eggs within the ovary. It can also help with menstrual cycle regulation [15, 16].

Vitamin D status has been studied within fertility clinics. Both pregnancy and live birth rates appear to be higher in women with adequate levels [17]. Risks of pregnancy loss and complications also appear to be lower [18, 19].

3. You’re Probably Deficient

Studies show that most people don’t have enough vitamin D.

Most government organizations define vitamin D insufficiency at < 20 ng/ml (50 nmol/L). Several medical societies and experts put this level at < 30 ng/ml (75 nmol/L) [20].

In most of the world, over 50% of people have levels less than 30 ng/ml [21-23]. Rates are higher in winter, and several groups have a notably worse deficiency. These include people that are overweight and people with dark skin that live far from the equator.

Among the US Hispanic population, roughly 70% of people have levels less than 20 ng/ml. For Black people, the rate is more than 80% [24].

For women with PCOS, vitamin D deficiency is also very common. Estimates put deficiency rates at 67 – 85% [25].

Unless you get a lot of year-round exposure to the midday sun, then you’re likely to be low in vitamin D. This is especially true for black or South Asian women living in the northern United States or Europe.

A simple blood test can confirm your requirements, so speak with your doctor.

Vitamin D3 Dosage For PCOS

In the absence of testing, experts in the field recommend 4000 IU (100 mcg) daily. 4000 IU is widely regarded as safe [26]. Doses of 10,000 IU have not been shown to cause toxicity in healthy people [27, 28].

3875 IU (97 mcg) daily is required for 97.5% of people to reach 20 ng/ml. 6200 IU (155 mcg) is needed to achieve 30 ng/ml [29]. This is much higher than the US Recommended Dietary Allowances due to an admitted statistical error [30]. At the time of writing, this error had not been corrected. The US RDA for vitamin D remains at an insufficient 600 IU.

Where To Get The Best Vitamin D Supplements

Vitamin D supplements come in two forms: D2 and D3. Vitamin D2 comes from plants while D3 is derived from animal sources.

D3 is generally considered better than D2. D3 is the type of vitamin D produced by your skin. It’s also more effective than D2 at raising your vitamin D status [31].

When selecting a product, choose a trusted brand with a reputation for quality assurance.

Theralogix is one such trusted brand within the PCOS community.

They offer a 3-month supply of 4000 IU vitamin D supplements for 27 cents a day. Use the link provided or type in Provider Referral Code (PRC) A29927 at checkout for 14% off the retail price.

The Bottom Line

Vitamin D is good for PCOS, yet most people are deficient. Unless you get year-round exposure to the midday sun, you’ll likely benefit from a vitamin D supplement. 4000 IU of vitamin D daily is widely regarded as safe. In the absence of testing, this level of supplementation is suitable for women with PCOS.


Can’t I get enough vitamin D from the sun? Yes. Exposure to sunlight is the best way to build your vitamin D levels. The key step here is getting enough. You need to have your skin exposed during the middle of the day when you also have the most risk of sunburn. The more skin you can expose the better. During the winter months, midday sun exposure may not be enough. Studies have found that recommended summer sunlight exposure levels are also not sufficient [32, 33]. Hence the high rates of insufficiency.

Can’t I get more vitamin D from food? Yes, there are many foods high in vitamin D. These include oily fish like salmon and tuna. Beef liver, eggs, and mushrooms also contain small amounts of vitamin D. Diet alone though is unlikely to provide sufficient vitamin D for thriving. See the National Institutes of Health for estimates of the vitamin D content of selected foods.

Isn’t vitamin D harmful without vitamin K? Yes and no. Vitamin D is only harmful when taking extremely high doses for extended periods. Under these circumstances, vitamin K may be protective. At more normal levels of 4,000 IU of vitamin D per day, vitamin K2 supplementation may be preferable but not essential. This article provides further information.

Ready to Take Action?

  • Join my free 30-Day PCOS Diet Challenge here. This is a unique program where you'll receive weekly meal plans, shopping lists, and helpful video lessons. You'll also be part of a motivated and inspiring community of like-minded women.

  • Download my free 3-Day PCOS Diet Meal Plan here. This is perfect for getting started if you aren't ready to commit to 30 days.

  • Join my PCOS Monthly Meal Planning Service here. This service includes hundreds of PCOS recipes within a pre-populated, yet customizable meal plan. It's designed to save you time and help you apply a PCOS diet.

  • Sign up for my Beat PCOS 10-Week Program. This is a comprehensive program that covers diet, PCOS-centric emotional eating, exercise, stress management, and much more. All within a support group environment. The 10-Week Program includes the same recipes and meal plan as my monthly meal planning service.


Back to Top


1Barrea, L., et al., Source and amount of carbohydrate in the diet and inflammation in women with polycystic ovary syndrome. Nutr Res Rev, 2018. 31(2): p. 291-301.

2Wang, J., et al., Hyperandrogenemia and insulin resistance: The chief culprit of polycystic ovary syndrome. Life Sciences, 2019. 236.

3González, F., Inflammation in Polycystic Ovary Syndrome: underpinning of insulin resistance and ovarian dysfunction. Steroids, 2012. 77(4): p. 300-5.

4González, F., et al., Hyperandrogenism sensitizes mononuclear cells to promote glucose-induced inflammation in lean reproductive-age women. Am J Physiol Endocrinol Metab, 2012. 302(3): p. E297-306.

5Popovic, M., G. Sartorius, and M. Christ-Crain, Chronic low-grade inflammation in polycystic ovary syndrome: is there a (patho)-physiological role for interleukin-1? Seminars in Immunopathology, 2019. 41(4): p. 447-459.

6Rostamtabar, M., et al., Pathophysiological roles of chronic low-grade inflammation mediators in polycystic ovary syndrome. J Cell Physiol, 2021. 236(2): p. 824-838.

7Rudnicka, E., et al., Chronic Low Grade Inflammation in Pathogenesis of PCOS. Int J Mol Sci, 2021. 22(7).

8Zhao, J.F., B.X. Li, and Q. Zhang, Vitamin D improves levels of hormonal, oxidative stress and inflammatory parameters in polycystic ovary syndrome: a meta-analysis study. Ann Palliat Med, 2021. 10(1): p. 169-183.

9Miao, C.Y., et al., Effect of vitamin D supplementation on polycystic ovary syndrome: A meta-analysis. Exp Ther Med, 2020. 19(4): p. 2641-2649.

10Łagowska, K., J. Bajerska, and M. Jamka, The Role of Vitamin D Oral Supplementation in Insulin Resistance in Women with Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients, 2018. 10(11).

11Wang, L., et al., Effects of vitamin D supplementation on metabolic parameters of women with polycystic ovary syndrome: a meta-analysis of randomized controlled trials. Gynecol Endocrinol, 2021. 37(5): p. 446-455.

12Luo, J., T. Li, and J. Yuan, Effectiveness of vitamin D supplementation on lipid profile in polycystic ovary syndrome women: a meta-analysis of randomized controlled trials. Ann Palliat Med, 2021. 10(1): p. 114-129.

13Gao, H., et al., The Effect of Vitamin D Supplementation on Blood Lipids in Patients with Polycystic Ovary Syndrome: A Meta-Analysis of Randomized Controlled Trials. Int J Endocrinol, 2021. 2021: p. 8849688.

14Moridi, I., et al., The Association between Vitamin D and Anti-Müllerian Hormone: A Systematic Review and Meta-Analysis. Nutrients, 2020. 12(6).

15Fang, F., et al., Effect of vitamin D supplementation on polycystic ovary syndrome: A systematic review and meta-analysis of randomized controlled trials. Complement Ther Clin Pract, 2017. 26: p. 53-60.

16Shojaei-Zarghani, S. and M. Rafraf, Resveratrol and Markers of Polycystic Ovary Syndrome: a Systematic Review of Animal and Clinical Studies. Reprod Sci, 2021.

17Chu, J., et al., Vitamin D and assisted reproductive treatment outcome: a systematic review and meta-analysis. Hum Reprod, 2018. 33(1): p. 65-80.

18Zhang, H., et al., Meta-analysis of the effect of the maternal vitamin D level on the risk of spontaneous pregnancy loss. Int J Gynaecol Obstet, 2017. 138(3): p. 242-249.

19Pilz, S., et al., The Role of Vitamin D in Fertility and during Pregnancy and Lactation: A Review of Clinical Data. Int J Environ Res Public Health, 2018. 15(10).

20Munns, C.F., et al., Global Consensus Recommendations on Prevention and Management of Nutritional Rickets. J Clin Endocrinol Metab, 2016. 101(2): p. 394-415.

21van Schoor, N. and P. Lips, Global Overview of Vitamin D Status. Endocrinol Metab Clin North Am, 2017. 46(4): p. 845-870.

22Cashman, K.D., et al., Vitamin D deficiency in Europe: pandemic? Am J Clin Nutr, 2016. 103(4): p. 1033-44.

23Palacios, C. and L. Gonzalez, Is vitamin D deficiency a major global public health problem? J Steroid Biochem Mol Biol, 2014. 144 Pt A: p. 138-45.

24Forrest, K.Y. and W.L. Stuhldreher, Prevalence and correlates of vitamin D deficiency in US adults. Nutr Res, 2011. 31(1): p. 48-54.

25Thomson, R.L., S. Spedding, and J.D. Buckley, Vitamin D in the aetiology and management of polycystic ovary syndrome. Clin Endocrinol (Oxf), 2012. 77(3): p. 343-50.

26Giustina, A., et al., Consensus statement from 2nd International Conference on Controversies in Vitamin D. Rev Endocr Metab Disord, 2020. 21(1): p. 89-116.

27Hathcock, J.N., et al., Risk assessment for vitamin D. Am J Clin Nutr, 2007. 85(1): p. 6-18.

28Ross, A.C., et al., The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know. J Clin Endocrinol Metab, 2011. 96(1): p. 53-8.

29Heaney, R., et al., Letter to Veugelers, P.J. and Ekwaru, J.P., A statistical error in the estimation of the recommended dietary allowance for vitamin D. Nutrients 2014, 6, 4472-4475; doi:10.3390/nu6104472. Nutrients, 2015. 7(3): p. 1688-90.

30Veugelers, P.J. and J.P. Ekwaru, A statistical error in the estimation of the recommended dietary allowance for vitamin D. Nutrients, 2014. 6(10): p. 4472-5.

31Balachandar, R., et al., Relative Efficacy of Vitamin D2 and Vitamin D3 in Improving Vitamin D Status: Systematic Review and Meta-Analysis. Nutrients, 2021. 13(10).

32Farrar, M.D., et al., Recommended summer sunlight exposure amounts fail to produce sufficient vitamin D status in UK adults of South Asian origin. Am J Clin Nutr, 2011. 94(5): p. 1219-24.

33Webb, A.R., et al., The role of sunlight exposure in determining the vitamin D status of the U.K. white adult population. Br J Dermatol, 2010. 163(5): p. 1050-5.

Leave a Comment