The product is D-Ribose combined with L-cysteine...
Ribose is manufactured in the body... *IF* the body has enough B2, and the metabolic processes of manufacturing is functioning properly.
If not, eat foods high in B2... and its co-factors. Raw milk supplies four, and perhaps more forms of B2.
Cysteine - raw milk... there are of course other sources for both of these things...
And as I stated metabolic processes must be functioning... sulfur cycles, methylation, etc... which are broken these days in most people due to poor, industrialized foods - read chronic fatigue, fibromyalgia, etc.
Man created this glutathione deficiency problem... by messing with natural processes and foods.