In RBCs, NADPH are produced exclusively via HMP shunt by the action of G6PD and are responsible to maintain membrane integrity preventing premature destruction. That is why G6PD deficient RBCs are Glucose 6 phosphate dehydrogenase (G6PD) deficiency: Video, Causes, & Meaning Osmosis Correcting glucose 6 phosphate dehydrogenase deficiency with a small molecule activator Nature Communications The potential link between inherited G6PD deficiency, oxidative stress, and vitamin D deficiency and the racial inequities in mortality associated with COVID 19 ScienceDirect