Symptoms of long Covid, such as typical fatigue and shortness of breath, can be reduced thanks to a supplement that combines vitamin C with an amino acid, L-arginine. This is demonstrated by the results of an Italian study published in the international journal Virology, which showed a significant improvement in strength and endurance.
I am trying to wrap my head around what I think I know about arginine, i.e., that it promotes viral activity (while lysine inhibits viruses.)