Characterization of TMAO productivity from carnitine challenge facilitates personalized nutrition and microbiome signatures discovery Microbiome Springer Nature Link Elucidation of an anaerobic pathway for metabolism of l carnitinederived butyrobetaine to trimethylamine in human gut bacteria PNAS Differential effects of oral and intravenous L carnitine on serum lipids: is the microbiota the answer? TMAO Is Both a Biomarker and a Renal Toxin Circulation Research