I’m not a chemist... but graphene is nothing but a crystalline form of pure carbon. Like diamonds and Bucky balls.
So graphene oxide would be CO or CO2. Carbon monoxide or carbon dioxide. Either of which, like dihydrogen monoxide, can be lethal in large doses, but we’ll probably be ok.
Did you read the article? Small doses at a time, booster shots , etc. It never leaves the body unless taking the supplements mentioned.
