Well-documented side effects from clinical trials include nausea, vomiting, diarrhea, and constipation
If you are using a liposomal format, the glutathione is protected by a phospholipid bilayer, making it less sensitive to the presence of food, though taking it on an empty stomach is still a great practice for maximum efficiency
Some risk factors which may be implicated or predispose a cat to pancreatitis in some cases are: Parasites: liver or pancreatic flukes, toxoplasmosis Bacterial: bacteria ascending from the gastro-intestinal tract into the pancreatic duct Certain viruses: Feline Calcivirus Blunt trauma: being run over or falling from a high place, for example Certain pesticides or medications have been brought into question by some vets and researchers Siamese cats seem to be slightly more predisposed to pancreatitis than other breeds
Lee, T.D., et al., Cloning and characterization of the human glutathione synthetase 5-flanking region