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 L Carnitine L Tartrate Powder 250g Pure : Amazon.co.uk: Health & Personal Care Get Rid of Fishy L Carnitine Smell: Essential Fixes Tonum L Carnitine Avoid Fishy Smell TikTok Healthy According to a randomized, double blind, placebo controlled clinical trial published in Elsevier journal Research in Autism Spectrum Disorders (2013), l carnitine supplementation demonstrated a significant therapeutic benefit in children L Carnitine: Does it help with weight loss?