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: Benefits and Side Effects Gene Food L carnitine tartrate supplementation in the fight against infectious disease Beneficial effects of l carnitine supplementation for weight management in overweight and obese adults: An updated systematic review and dose response meta analysis of randomized controlled trials ScienceDirect