Comparative Effectiveness of Myo-Inositol and Carnitine in the Management of Hyperinsulinemic Polycystic Ovary Syndrome

Polycystic Ovarian Syndrome (PCOS) is a common endocrine disorder in women of reproductive age, with insulin resistance and hyperinsulinemia playing key roles in its development. Although metformin is widely used to improve insulin sensitivity, its gastrointestinal side effects have increased interest in alternative therapies such as Myo-Inositol (MI) and L-carnitine. This review compares the mechanisms, clinical efficacy, and safety of MI and L-carnitine in the management of hyperinsulinemic PCOS. A comprehensive literature search was conducted across PubMed, Cochrane, Scopus, including Randomised Controlled Trials and mechanistic studies published from 2000 to 2024. Relevant evidence assessing the efficacy and safety of Myo-inositol and L-carnitine in PCOS were analyzed. MI functions as a crucial mediator of insulin signaling and helps restore insulin sensitivity, improve ovarian function, and regulate ovulation by maintaining the ovarian myo-inositol to D-chiro-inositol balance. L-carnitine enhances mitochondrial fatty acid transport and β-oxidation, improves energy metabolism, and reduces oxidative stress. Clinical studies have shown that both supplements significantly lower fasting insulin levels, improve insulin resistance, and reduce hyperandrogenic symptoms. MI demonstrates greater benefits in improving ovulation, menstrual regularity, and fertility-related outcomes, while L-carnitine appears more effective in promoting weight loss, reducing body mass index, and improving metabolic parameters. Overall, both MI and L-carnitine are safe and promising therapeutic options for women with hyperinsulinemic PCOS, although further large-scale studies are needed to determine optimal treatment approaches.