l carnitine fishy odor trimethylamine side effect FISH SYNDROME (TRIMETHYLAMINURIA), Causes, Signs and Symptoms, Diagnosis and Treatment Can L-Carnitine Cause Side Effects?
Description
Neuropharmacological effects 5.2.1

Improving the efficiency of carnitine absorption and utilization is also possible by improving the mechanism of carnitine transport, such as increasing the expression or activity of carnitine transporters [199, 200]

For that, you need pure, 100% L-Carnitine
Elevated plasma membrane OCTN2 carnitine transporter expression was observed in vegetarians compensating for lower carnitine levels obtained from the diet
