Endothelial dysfunction is common in both Long COVID and ME CFS and has been linked to symptoms like fatigue, chest pain, and brain fog. Research suggests that certain supplementslike L arginine, CoQ10, curcumin, and Brain Fog" is a lay term used to describe fluctuating mild memory loss that is inappropriate for a person's age. It may include forgetfulness, spaciness, confusion, decreased ability to pay attention, an Fatigue and Brain Fog Kit Rootcology L Carnitine Benefits for Chronic Fatigue Syndrome