Injectable carnitine vs oral version comparison? Injectable vs Oral L Carnitine: Which Works Better? AWP Dont waste money on supplements like L carnitine. First focus on your diet and training. Also, oral L carnitine has low bioavailability. Injectable forms may absorb better, but diet and training L Carnitine Oral Bioavailability NOW l Carnitine Supplement Levocarnitine Liv Hospital Injectable L carnitine vs oral? For me, absorption, fewer GI issues, & energy performance gains make injections the winner. #LCarnitine #Injectable #Bioavailability #MetabolicHealth #EnergyBoost