The effects of L carnitine in children with kidney failure undergoing dialysis: a systematic review Pediatric Nephrology Springer Nature Link 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 Early research into L carnitine was often cited as underwhelming, showing negligible changes in muscle carnitine content and fat loss outcomes. However, these findings may have been limited by a short study window Acetyl L Carnitine & Reviews Thorne