Can choline supplementation cause a fishy body odor? Consensus L Carnitine Erectile Dysfunction: What the Evidence Actually Shows L Carnitine Erectile Dysfunction: What the Evidence Actually Shows 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. Carnitine and acetyl L carnitine Neuroneeds