PCOS: The Condition Affecting 1 in 10 Women That Nobody Explains Properly

PCOS — polycystic ovary syndrome — is the most common endocrine disorder in women of reproductive age, affecting approximately 1 in 10 women worldwide. Yet despite its prevalence, it remains one of the most poorly understood, inconsistently treated, and inadequately explained conditions in women's health. Most women with PCOS are told it's a hormone problem, given the pill or metformin, and sent away with minimal understanding of what's actually happening in their body.

This article explains PCOS clearly — what it is, why it happens, and what the evidence says about addressing it nutritionally, including the important role of vitamin D3.

What PCOS Actually Is

PCOS is not primarily a condition of the ovaries. It is a complex metabolic-endocrine disorder characterised by hyperandrogenaemia (elevated androgens — testosterone and related hormones), ovulatory dysfunction (irregular or absent periods), and insulin resistance in the majority of cases. The polycystic appearance of the ovaries on ultrasound is a consequence of the hormonal environment, not its cause.

The core driver in most PCOS presentations is insulin resistance — the inability of cells to respond normally to insulin signals. Elevated insulin levels stimulate the ovaries to produce excess androgens. Elevated androgens suppress ovulation, disrupt the menstrual cycle, and produce the characteristic symptoms: irregular periods, excess facial and body hair (hirsutism), acne, scalp hair thinning, and in many cases weight gain that is resistant to standard dietary approaches.

Vitamin D3 and PCOS

Vitamin D3 deficiency is found at significantly elevated rates in women with PCOS compared to controls — with prevalence of deficiency estimated at 67-85% in PCOS populations across multiple studies. This is not merely an association. Vitamin D3 plays direct biological roles in several of the pathways disrupted in PCOS. Vitamin D3 improves insulin sensitivity through its effects on insulin receptor expression and glucose transporter function — directly addressing the core metabolic dysfunction in PCOS. It modulates androgen production in ovarian cells through vitamin D receptor-mediated pathways. It regulates anti-Müllerian hormone (AMH) production, which is elevated in PCOS and contributes to ovulatory dysfunction. Multiple intervention studies have found that vitamin D3 supplementation in deficient women with PCOS improves insulin resistance, reduces testosterone levels, improves menstrual regularity, and in some studies, improves fertility outcomes.

Magnesium and PCOS

Magnesium deficiency is also consistently found in PCOS, and its role in insulin signalling makes it directly relevant to the core metabolic dysfunction. Magnesium is required for insulin receptor function and glucose metabolism enzymes. Low magnesium worsens insulin resistance, which worsens androgen excess, which worsens PCOS. Magnesium bisglycinate supplementation improves insulin sensitivity and reduces inflammatory markers in women with PCOS in clinical studies.

Inositol: The Most Evidence-Supported Nutritional Intervention

Myo-inositol and D-chiro-inositol — forms of a B-vitamin-like compound — are the most extensively studied nutritional interventions for PCOS, with multiple randomised controlled trials demonstrating improvements in insulin sensitivity, ovulation rates, testosterone levels, and in women undergoing IVF, egg quality. A combination of myo-inositol and D-chiro-inositol at a 40:1 ratio is the most evidence-supported formulation.

NeuroThrive™ products are food supplements and are not intended to diagnose, treat, or cure any medical condition. PCOS requires medical diagnosis and management. Please work with your GP or gynaecologist.