Carnitine: the claims and why it may not work If you are like a lot of people, you may have never heard of carnitine but this important nutrient is critical for our body's ability to optimally burn fat required for energy. The adverse effects of long term l carnitine supplementation on liver and kidney function in rats L Liu, D M Zhang, M X Wang, C Y Fan, F Zhou, S J Wang, L D Kong, 2015 Role of L carnitine in female infertility Reproductive Biology and Endocrinology Springer Nature Link L Carnitine: Benefits, Side Effects, And Dosage, Per Dietitians Role of L carnitine in Cardiovascular Health: Literature Review Cureus