Odd that there'd be a patent on combining glycine with NAC. There's no reason they have to be in a combination pill (other than not wanting to track more pills). If you're not a perfect methylator (only about 25% of us are) it makes sense to take glycine as betaine (trimethyl glycine/TMG) just to sidestep an internal methylation step.

I can't help but wonder if methylation is a confounding factor here. I've seen no data on whether this gets poorer as people age. I suspect not, but even so there is a population distribution (basically quartiles) of the SNPs involved.