Iv said it loads of times about hair testing but I reckon the only reason no one ever mentions it is because t would open a whole can of worms because of how thorough it is.

It can detect anything you have taken for as long as that hair has grown on your body.

Urine and blood tests have nothing on a simple un invasive hair test but its not used or never even mentioned? Why?

I also think another reason may be that it would be so easy for anyone to collect a hair from the athlete to test. It could never be proved 100% that the hair was from that athlete but if someone being filmed actually plucked a hair from them and did not stop filming until that hair had been tested to try and prove where it came from and it showed past ped use it would cast a major doubt over that athlete to the point where they would need to carry out a public test to disprove it.