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 L Carnitine Veg Capsules NOW Foods Amino Acids L Carnitine Tartrate SFI Health US Patient reported treatment outcomes in ME CFS and long COVID PNAS Can CoQ10, L Carnitine, and B Vitamins Support Cellular Energy in Long COVID and ME CFS? RTHM Neurological manifestations of long COVID syndrome: a narrative review Maria Ioanna Stefanou, Lina Palaiodimou, Eleni Bakola, Nikolaos Smyrnis, Marianna Papadopoulou, George P. Paraskevas, Emmanouil Rizos, Eleni Boutati, Nikolaos Grigoriadis