While l-carnitine bioavailability is fairly low 14-18%, acetyl l carnitine increases to 43% and Liposomal acetyl l carnitine it goes WAY up. For me I will stick with regular acetyl l carnitine and just take 500mg 2x ED.

Kinetics, pharmacokinetics, and regulation of L-carnitine and acetyl-L-carnitine metabolism - PubMed