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 Does Carnitine Cause Body Odor? Lume Deodorant Treatments of trimethylaminuria: where we are and where we might be heading ScienceDirect Overview 2023 FSU iGEM Investigating the Association between Low Trimethylamine N Oxide Level TACG Dove Medical Press Human model of primary carnitine deficiency cardiomyopathy reveals ferroptosis as a novel mechanism: Stem Cell Reports