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. L Carnitine: Benefits, Uses, Side Effects, and More Acetyl l Carnitine Ameliorates Metabolic and Endocrine Alterations in Women with PCOS: A Double Blind Randomized Clinical Trial Advances in Therapy Springer Nature Link How Carnitine Transport Plays a Pivotal Role in Male Fertility Medical Electronic Systems 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.,