When to Take L Carnitine for Optimal Training Benefits Transparent Labs How To Use Creatine for Cutting vs Bulking? AS IT IS Nutrition L carnitine is involved in transporting fatty acids into your cells' mitochondria to be burned for energy. During a bulk, the idea is to gain muscle, ideally with minirmal fat gain. Here's how, L carnitine's acts as a fat burning supplement. During bulking periods, it can help limit fat gains and make a cleaner bulk. If you're cutting, it can help transport the fat you have into