Last time I looked at the data, female suicide attempts were overwhelmingly pharmacological drug abuse or exsanguination and then followed by jumping from a height. These are methods that can be prevented if you're found quick enough or if you fuck it up (not high enough dosage, not deep enough cut, not high enough jumping point).
Meanwhile males hardly did those tasks and often decided on hanging or firearms, which were harder to fuck up. Firearms leave no time for someone to find you while hanging requires them to find you in the act.