Vitamin D deficiency is remarkably common in PCOS — affecting 67-85% of people with the condition, significantly higher than the general population.
Why it matters for PCOS:
• Low vitamin D is associated with worse insulin resistance • Deficiency correlates with higher androgen levels • May contribute to inflammation • Associated with poorer fertility outcomes • Linked to mood disorders (which are already more common in PCOS)
What supplementation may improve:
• Insulin sensitivity (several RCTs show improvement) • Inflammatory markers • Menstrual regularity (in some studies) • Mood and energy
Testing: Ask for a 25-hydroxyvitamin D blood test. Optimal levels are generally considered 40-60 ng/mL, though definitions of "sufficient" vary (most labs say >30 ng/mL).
Dosing: Depends on your current level. Common ranges in studies: • Mild deficiency: 2,000-4,000 IU daily • Moderate deficiency: 4,000-5,000 IU daily • Severe deficiency: Your doctor may recommend a high-dose loading protocol
Vitamin D is fat-soluble, so take it with a meal containing fat for better absorption. Re-test after 3 months to check your levels.
This is one of the simplest and best-supported interventions for PCOS — test your levels and supplement if deficient.