Health The Link Between Vitamin D, Hormones, and PCOS
Mar 23, 2022 4 min. read

Irregular periods? Excessive body hair? Weight gain or thinning hair? These could be symptoms of polycystic ovary syndrome, or PCOS, a female endocrine disorder. PCOS is a sneaky condition because, although it’s estimated that one in five women suffer from it, many don’t even know they have it! But it’s important to know about: PCOS is the leading cause of reproductive issues and infertility.

Chances are that at least one of your female friends has experienced some of these symptoms. Maybe even you. But PCOS is not a well-understood disorder, whether by doctors or patients, and that leads to massive underdiagnosis. Studies show it can take at least two years and three different doctors to get a PCOS diagnosis.

But what if a simple supplement could reduce your risk of PCOS and help manage symptoms?

It turns out that vitamin D, one of four vitamins in the fat-soluble family, is not just for healthy bones! It may play a role in the management of PCOS too.

What exactly is PCOS?

In PCOS, the ovaries produce an abnormal amount of male sex hormones, including testosterone (yes, women do make and need small amounts!). Low estrogen levels, insulin resistance, and small cysts (fluid-filled sacs) that form in the ovaries can all be associated with PCOS as well.

So what happens if PCOS symptoms get ignored? Unfortunately, other health issues may emerge, like type 2 diabetes, decreased iron levels, and elevated cholesterol levels and heart disease.

Treating symptoms, then, is important. And even though the cause of PCOS is not clearly understood, the symptoms, as confusing as they may seem, are mostly rooted in endocrine dysfunction, which gives an important clue to what an effective treatment might look like.

How can vitamin D help?

There’s no doubt that vitamin D is a nutritional hero, contributing to strong bones, low inflammatory markers, a robust immune system, and a healthy glucose metabolism and endocrine system. It may also have a tie to PCOS: In one study, researchers found that a staggering 67-85 percent of women with PCOS were deficient in vitamin D. While low vitamin D status does not cause PCOS, some studies suggest it may worsen symptoms.

Other studies have shown that vitamin D supplementation improves blood sugar levels, hormone function, and cholesterol levels in women with PCOS.

Blood sugar levels

Insulin resistance is a common feature of PCOS. Left untreated, it can develop into type 2 diabetes. A drug called metformin, often prescribed to help manage high blood sugar levels, can be effective, but side effects can include nausea, vomiting, and diarrhea.

Enter vitamin D. Studies show that, like metformin, daily vitamin D supplementation can help to reduce fasting glucose levels and insulin resistance. And there are no known side effects of taking vitamin D to maintain healthy levels.

Hormone function

Women with PCOS also exhibit high levels of male sex hormones (androgens), which can cause excess hair growth and skin issues. Vitamin D supplementation can help to lower androgen levels and, when combined with calcium, can help regulate menstrual and ovulation cycles.

Cholesterol levels

Insulin resistance and elevated androgen levels are both associated with altered cholesterol levels in women with PCOS. Vitamin D and calcium supplementation has beneficial effects on cholesterol markers. Left untreated, high cholesterol can contribute to an increased risk of heart disease. 

How to get more vitamin D

Given the benefits of vitamin D for symptoms of PCOS, it’s a good idea to make this nutrient part of your health routine. So, how do you do that?

The easiest way to increase vitamin D levels is through sun exposure. Your largest organ, the skin, synthesizes vitamin D when exposed to UV rays. Just twenty minutes a day will maintain healthy levels. Keep in mind, though, that this option is dependent on your geographic location. If you live in the northern hemisphere, daily sun exposure might be unrealistic.

How about food? In their natural state, few foods get a gold star for being exceptionally high in vitamin D but egg yolks, cheese, and fatty fish, including trout, salmon, tuna, and mackerel, are all excellent sources. Fortified cow’s milk and plant-based milks (soy, almond, oat, etc.) are also good. If you consume these foods – great! But keep in mind that you’re not always getting the active form of vitamin D in these foods, so it’s hard to know how much you’re consuming.

Depending on your lifestyle, the most reliable way to maintain healthy vitamin D levels may be taking a daily supplement. This is especially true if you’re vegan or vegetarian and don’t eat fish, eggs, or cheese regularly. Be aware, though, that many brands offer supplementation in the form of D2, which has been found to be a less bioavailable form compared to D3, meaning it's less able to raise vitamin D levels in the body. 

25 mcg vitamin D3 per serving

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author Medically reviewed by Belinda McCall, CHHP
Medically reviewed by Belinda McCall, CHHP

Belinda McCall is a Certified Holistic Nutritionist, AADP Board Certified Holistic Health Practitioner, and nutrition coach at Wellory. Follow Belinda on Instagram at @womanbeewell, where she helps empower women to take control of their health and wellness.