If the desire is to add ribose, one can buy and supplement d-Ribose.
If the desire is simply to increase glutathione, vitamin C can regenerate up to about 50% of it in the body which is massive, and one can make a DIY liposomal version -- or at least emulsified homogenized, which seems to absorb better, whether or not it is some % liposomal -- fairly affordably after an initial small investment.