Glycine Propionyl L Carnitine & ED : Benefits, Effects & Uses Allo Health Blog L Carnitine: Uses, Benefits, Dosage, and Side Effects StrengthLog Carnitine has a central role in fat metabolism. During the overnight fasted state and in exercise performed at low to moderate intensity, long chain fatty acids serve as the primary energy source for 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