I've run across this on Heartfixer and several forums: "Sulfite is neurotoxic. Sulfite will be over produced by the CBS up regulation, and then requires conversion in to the less toxic sulfate molecule by the enzyme Sulfite Oxidase (SUOX). SUOX can easily be overwhelmed. Molybdenum is required for SUOX function, and is typically depleted in CBS (+/+) or (+/-) individuals. Molybdenum supplementation (3 drops or 75 mcg of e-lyte Molybdenum twice a day), Boron 3 mg/day, Vitamin E succinate 400 IU/day, and hydroxy-B12 2000 mcg/day are also utilized to speed up SUOX activity." Several things are happening that point to a sulfite/ammonia problem for me. Now I've just taken a bit of hydroxyB12 (1,000 mcg) and my brain fog / hypoxia is clearing. Same thing last night. Before that, I was doing the deadlock quartet. This fog I keep getting was not a problem until I started methylation. It is very much like the grogginess that always came on at high altitude (11,000') back in my hiking days, which would be hypoxia. I can't keep my eyes open -- that kind of grogginess. Why would hydroxyB12 help with this, does anyone know?