L Carnitine for Weight Loss: How It Works, Dosage & Best Supplement Zeelab Pharmacy Carnitine: the claims and why it may not work Will this make you smell like fish?! Pcos L Carnitine Benefits, Side Effects & Dosage SelfDecode Supplements 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.