Too many people are unaware of the hazards that N2O (nitrous oxide). Used in dental and other procedures where a mild anesthetic is needed and also used as part of a mix with more potent inhalant anesthetics. N2O immediately permanently oxidizes circulating MeCbl and AdoCbl. Once N2O connects there is no enzyme or ATP that can reclaim it. It is rapidly flushed from the body. Occasionally someone ends up in a coma from N2O or goes home and goes into methyltrap in the body and brain. If not corrected that can cause SACD, Subacute Combined Degeneration rapidly and other damage. As there is no limit on how much B12 that can be destroyed by N2O because it is a simple direct immediate oxidation reaction, just like glutathione does to B12, too much will and does cause methyltrap. Before having nitrous oxide I take at least 10mg of sublinguals. Then after leaving the office I do 1mg at a time for the rest of the day to get my b12 in the CNS back up to a functional level. Most ordinary people don't notice the b12 destruction. We can feel it immediately. Nitrous oxide recreational usage is dangerous to us. It can cause brain damage and coma. So those of you who went to the dentist or had anesthesia and don't feel right, some sublingual b12 MeCbl and AdoCbl can restore the B12 and prevent sustained damage.