While most COVID-19 therapeutic efforts have understandably focused on vaccines from the public health perspective, less emphasis was directed at other therapeutic options either independently or conjointly with vaccination. Current evidence strongly suggests that the Kynurenine pathway of tryptophan metabolism is the top target of COVID-19 infection and a major determinant of its pathophysiology... Depletion of NAD+ and ATP are the end result of COVID-19 infection...Replenishing NAD+ levels (in COVID) can be achieved by using suitable NAD+ precursors. Careful choice of precursors is however important. Use of Trp is inadvisable for two reasons: increased production of Kyn metabolites and the powerful AhR agonist IPA. Similarly, nicotinic acid is unlikely to contribute to NAD+ replenishment, given that the Preiss-Handler pathway will also be blocked. This leaves nicotinamide or its riboside...