Effects of carnitine on glucose and lipid metabolic profiles and fertility outcomes in women with polycystic ovary syndrome: A systematic review and metaanalysis Gong 2023 Clinical Endocrinology Wiley Online Library Role of Oxidative Stress and Carnitine in PCOS Patients IntechOpen Carnitine Metabolon L Carnitine has become one of the most commonly asked about supplements over the past 18 months and I can see why when looking at all the research that has come out about it over the last 2ish years., L carnitine is a naturally occurring amino acid structure that is made in the human brain, liver, and kidneys. L carnitine plays a critical role in energy production, as it converts fat into energy.