Unlock Peak Performance & Fertility with L Carnitine! Did you know that injectable L Carnitine is a game changer compared to oral supplements? While oral L Carnitine has low bioavailability (only ~14 18% 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 L Carnitine Oral Bioavailability NOW l Carnitine Supplement Intestinal microbiota metabolism of l carnitine, a nutrient in red meat, promotes atherosclerosis Nature Medicine