Vitamin D and PCOS: Symptoms, Benefits and Why Low Levels Are Common
- Lisa Smith Nutritionist
- Mar 24
- 6 min read
If you have PCOS and struggle with fatigue, low mood, frequent infections or difficulty losing weight, vitamin D may be one piece of the puzzle worth exploring.
Vitamin D deficiency is common in the UK, particularly during the autumn and winter months when sunlight exposure is limited. Research also suggests that low vitamin D levels may be more common in women with PCOS compared with the general population.
While vitamin D is not a cure for PCOS, maintaining healthy levels may support overall health and wellbeing, including bone health, immune function and energy levels.
In this article, we'll explore why vitamin D matters, the signs of deficiency, how it relates to PCOS and what practical steps you can take to support healthy levels.
What Is Vitamin D?
Vitamin D is a fat-soluble vitamin that acts more like a hormone in the body. It plays an important role in:
Bone and muscle health
Immune function
Mood regulation
Cell growth and repair
Calcium absorption
Unlike most vitamins, vitamin D can be produced by the skin when exposed to sunlight. However, in the UK, sunlight exposure is often insufficient for much of the year, making deficiency relatively common.
Why Is Vitamin D Important for Women With PCOS?
PCOS affects far more than reproductive health. It is increasingly recognised as a metabolic and hormonal condition that can influence energy, weight, blood sugar regulation and long-term health.
Vitamin D may play a role in several areas that are relevant to women with PCOS, including:
Insulin Sensitivity
Insulin resistance is common in PCOS and can contribute to cravings, weight gain and difficulties with ovulation.
Some studies suggest that vitamin D may influence insulin sensitivity, although more research is needed to fully understand this relationship.
Reproductive Health
Research has explored links between vitamin D status and menstrual cycle regularity, ovulation and fertility outcomes. While findings are mixed, maintaining adequate vitamin D levels is considered important for general reproductive health.
Mood and Energy
Low vitamin D levels have been associated with symptoms such as fatigue and low mood. Although these symptoms can have many causes, vitamin D deficiency is one potential factor worth investigating.
Bone Health
Women with PCOS may spend years focusing on hormones and fertility, but long-term bone health is equally important. Vitamin D helps the body absorb calcium and supports healthy bones throughout life.
Why Is Vitamin D Deficiency Common in PCOS?
There is likely no single reason why low vitamin D levels are more frequently seen in women with PCOS.
Several factors may contribute:
Limited sunlight exposure in the UK
Spending more time indoors
Low dietary intake of vitamin D-rich foods
Higher body fat levels, which may affect circulating vitamin D levels
Lifestyle factors that reduce outdoor activity
It's also important to remember that vitamin D deficiency is common in the wider population, not just in women with PCOS.
Symptoms of Low Vitamin D
Vitamin D deficiency doesn't always cause obvious symptoms, but some women may experience:
Fatigue or low energy
Low mood
Muscle aches or weakness
Frequent infections
Poor recovery from exercise
Reduced motivation
Bone or joint discomfort
These symptoms can overlap with other nutritional deficiencies and health concerns, which is why testing can be useful rather than relying on symptoms alone.
Could Low Vitamin D Be Making PCOS Symptoms Worse?
Low vitamin D levels are unlikely to be the sole cause of PCOS symptoms. However, deficiency may contribute to factors that can make managing PCOS feel more difficult.
For example, women experiencing fatigue may find it harder to:
Prepare balanced meals
Exercise consistently
Manage stress
Maintain healthy habits
Low energy can also make cravings and emotional eating more challenging to navigate.
This is why I take a whole-person approach when working with clients.
Fatigue may be influenced by several factors, including blood sugar balance, sleep quality, stress, iron status, vitamin B12, thyroid function and vitamin D levels.
How Do You Test Vitamin D Levels?
Vitamin D status is measured using a blood test called:
25-hydroxyvitamin D (25(OH)D)
Testing may be available through your GP in certain circumstances or through private testing providers.
Testing can help identify whether vitamin D levels are adequate, insufficient or deficient and guide appropriate recommendations.
If you're experiencing persistent fatigue, it's often worth considering a broader review rather than looking at vitamin D in isolation.
Should Women With PCOS Take Vitamin D Supplements?
There is no one-size-fits-all answer.
The UK government recommends that everyone consider a daily vitamin D supplement during the autumn and winter months because sunlight exposure is limited.
Additional supplementation may be appropriate for some individuals, particularly if deficiency has been identified through testing.
However, more is not always better. High doses should only be taken under appropriate guidance, as excessive vitamin D intake can be harmful.
Food Sources of Vitamin D
Although food alone is often not enough to maintain optimal levels, including vitamin D-rich foods can help support overall intake.
Food | Vitamin D Source |
Salmon | Excellent source |
Sardines | Excellent source |
Mackerel | Excellent source |
Egg yolks | Moderate source |
Fortified dairy products | Variable |
Fortified plant milks | Variable |
Fortified breakfast cereals | Variable |
5 Practical Ways to Support Healthy Vitamin D Levels
1. Spend Time Outdoors Regularly
Sunlight exposure remains one of the most effective ways to support vitamin D production during the spring and summer months.
2. Include Oily Fish Weekly
Aim to include oily fish such as salmon, sardines or mackerel regularly if suitable for your dietary preferences.
3. Consider Testing If Symptoms Persist
Persistent fatigue, low mood or recurring infections may warrant further investigation.
4. Focus on Overall Nutritional Health
Vitamin D is only one part of the picture. Balanced meals containing adequate protein, fibre and healthy fats can support energy and appetite regulation.
5. Seek Personalised Support
If you're struggling with ongoing symptoms, a personalised assessment can help identify which factors may be contributing.
Vitamin D deficiency is common in the UK and may be more common in women with PCOS.
While vitamin D is not a cure for PCOS, maintaining healthy levels may support overall health, including bone health, immune function, mood and energy.
If you're experiencing fatigue, cravings or low energy, it's worth remembering that vitamin D is just one potential piece of a much larger picture. Looking at blood sugar balance, nutrition, sleep, stress and other nutritional factors often provides a more complete understanding of what's driving symptoms.
If you struggle with cravings and low energy download my free guide to protein, cravings, meals and practical PCOS nutrition.
Frequently Asked Questions
Does vitamin D help PCOS?
Vitamin D may support aspects of health that are relevant to PCOS, including bone health, immune function and insulin sensitivity. However, it should be viewed as part of a broader nutrition and lifestyle approach.
Are women with PCOS more likely to be vitamin D deficient?
Research suggests that low vitamin D levels may be more common in women with PCOS, although deficiency is also widespread in the general population.
Can low vitamin D cause fatigue?
Fatigue is one possible symptom of vitamin D deficiency, but many other factors can contribute to low energy levels.
What test checks vitamin D levels?
Vitamin D status is typically assessed using a 25-hydroxyvitamin D blood test.
Should I take vitamin D every day?
Government guidance recommends considering a daily vitamin D supplement during autumn and winter in the UK. Individual requirements may vary.
Related PCOS Articles
You may also find these helpful:
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Updated June 2026 to reflect new PCOS research and nutrition strategies.
Disclaimer: This content is for educational purposes only and is not a substitute for personalised medical advice. Always check with your GP or healthcare provider before starting new supplements, especially if you’re taking medication or have a medical condition.
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