L-carnitine deficiency can be observed in the following cases- Genetic probability - Parents may pass this deficiency down to their kids. Vegans or vegetarians - Since carnitine is of animal origin, those individuals on an exclusively plant-based diet may end up with an L-carnitine deficiency. PolyCystic Ovarian Syndrome (PCOS)- Women with PCOS have low levels of carnitine. Undue stress - Those struggling from prolonged periods of stress may have carnitine deficiency as L-carnitine is essential in combating stress. High-intensity exercise - Athletes who undergo intense training over the long-term may experience a decrease in L-carnitine stores. Medications - Those who are on medicines like valproic acid (used to treat seizures or bipolar syndrome) may experience a dip in L-carnitine levels.