PDF) Comparison of pharmacokinetics of L carnitine, Acetyl L carnitine and Propionyl Lcarnitine after single oral administration of L carnitine in healthy volunteers Enhanced Bioavailability of L Carnitine After Painless Intradermal Delivery vs. Oral Administration in Rats Pharmaceutical Research Springer Nature Link Injectable L carnitine works better than oral because it goes straight into your bloodstream, giving almost 100% of absorption versus only 518% with capsules or liquid. Oral L carnitine can take upto 4 L Carnitine Injection Home Delivered Levocarnitine Oral Solution: Package Insert Prescribing Info