I don´t want to provoke anyone, I just hope that we can discuss this subject. I neither don´t want to be a party in the case of the methylation protocols as they surely have to be individualised. If methylation really works there will be a detox and release of toxins, including heavy metals. As methylation as an end product produces glutathione, that bind/conjugate with the help of GST -enzymes, this will lead to detoxification . If the GST-enzymes then aren´t in place, probably most because of defects in GST genes, this will not work well and might well give symptoms from toxins. I heard a researcher, knowledgeable in this, warn people, with GST gene defects, to try detoxification protocols as these might cause toxins "float around" without being conjugated to glutathione. I am sorry I can´t express this in a good way, but I think you that are interested can check this with other sources. So my guess is that people might get sick from @Freddd ´s protocol because it works. The methylation works maybe too good for some. Richvank also posted about this possible, negative effect from increased methylation by the protocol proposed by him. It is a double-edged sword to get it going again if more toxins are stored in the body than the detoxification pathways can handle. Side-effects from hydroxy-, but not from methylcobalamin, should be caused by something else.