L Carnitine: Benefits, Uses, Side Effects, and More Did You Know? Some people report a fishy smell after supplementing with L carnitine. This happens because certain gut bacteria convert carnitine to trimethylamine, a malodorous compound found in rotting fish. Acetyl L Carnitine Allergy: Symptoms and Treatment Options (2026) Wyndly Revisiting the Role of Carnitine in Heart Disease Through the Lens of the Gut Microbiota Comparison of short term and long term effects of peroral L carnitine intake: clinical implications of elevated TMAO levels in cardiovascular complications What is Carnitine?