This post was updated on March 13th, 2023
By Kym Campbell, BSc. | Updated March 13th, 2023
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 .
- 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 . 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 . 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) .
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% .
For women with PCOS, vitamin D deficiency is also very common. Estimates put deficiency rates at 67 – 85% .
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 . 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 . This is much higher than the US Recommended Dietary Allowances due to an admitted statistical error . 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 .
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.
Ready To Try A PCOS Diet?
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.
Combining rigorous science and clinical advice with a pragmatic approach to habit change, Kym is on a mission to show other women how to take back control of their health and fertility. Read more about Kym and her team here.
Quick Disclosure: Some of the links on this page may be affiliate links. This means that when you use them to purchase something, it won't cost you more but I may get paid a commission for referring you. In order to avoid any prejudice, I only recommend products that I personally use or would have recommended anyways.
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