Systemic regulation of L carnitine in nutritional metabolism in zebrafish, Danio rerio Scientific Reports Most oral L carnitine supplements are glorified flavored chemical waters., , Low bioavailability = very little of it actually gets picked up for use by the body., , So when companies sell $40$60 Carnitine Treatment Organic Acidemia Association Frontiers L carnitine prevents lenvatinib induced muscle toxicity without impairment of the anti angiogenic efficacy Enhanced Bioavailability of L Carnitine After Painless Intradermal Delivery vs. Oral Administration in Rats Pharmaceutical Research Springer Nature Link