Can Acetyl L Carnitine Help Clear Brain Fog and Fatigue in Long COVID and ME CFS? RTHM L Carnitine is Underrated. New Meta Review Reminds Us Why. Full article: L Carnitine conjugated nanoparticles to promote permeation across bloodbrain barrier and to target glioma cells for drug delivery via the novel organic cation carnitine transporter OCTN2 Stability enhancement and formulation development of l Carnitine fast dissolving pellets through pro drug strategy ScienceDirect L carnitine supplements bioavailability is very less and according to some studies it takes 8 to 12 weeks for for loss results, so if you decide to supplement with oral L carnitine do take it in