You do need to do some research on this method. According to a tens year long study in the U.S., by Harvard, the success rate for this method is 1.5%, so it has a 1 in 67 chance of working- when it does work it is usually from powerful opioids. The stury is called Lethality of Suicide Methods, and if you search by this title on google it will likely be the second choice that shows up and you can see the details of the study. Ctb by any method is difficult, many people have been on this site for quite a while trying to settle on a method, sinice none are easy, and they typically require quite a bit of planning to be confident that they will work.