L carnitine supplements can cause a fishy odor in the breath, sweat, and urine. This is likely due to the formation of trimethylamine (TMA). TMA is also responsible for the pungent smell of Trimethylamine N Oxide From Gut Microbiota in Chronic Kidney Disease Patients: Focus on Diet Journal of Renal Nutrition Frontiers A mixture of postbiotics tyndallized probiotics reduces trimethylamine (TMA) in trimethylaminuria models: Evidence from in vitro and in vivo studies Acetyl L Carnitine: Benefits and Side Effects Gene Food Frontiers Trimethylamine N Oxide Pathway: A Potential Target for the Treatment of MAFLD Potential Adverse Effects of L Carnitine Marnys