When to take L carnitine: Dosage, forms, and side effects L Carnitine: Unveiling the Science Behind its Role in Effective Weight Loss Aesthetics 360 Lash & MedSpa Acetyl L Carnitine and Erectile Dysfunction NIH 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 Amazon.com: Nutricost Acetyl L Carnitine 500mg, 180 Capsules Non GMO and Gluten Free (2 Bottles) : Health & Household