You have to have 1" of hair to take the test or they will pull it from somewhere else where you will fail..........I went through that when I went to the oil rigs.....bad news bro......I quit smoking dope for 3 months, cut my hair down to 1/2" twice and let it grow out the final month. 1" is considered to be 3 months growth for the test so they are only testing the last 90 days.....my hair grows 1/2" a month so I could have got away with just over two months. From my studies I found that it's in your blood for 5 days from your last smoke and therefore going into your hair folicles for that time........so you need an inch of hair growth time and 5 more days to be clean.... 9 guys started the same class I did and 5 were bounced for failing the tests......they had used the shampoos and other ways to hide it, but got caught....the bleaching might help but the fact is they're looking at picograms.....so the test is in the range of 1000(actually, I think 10,000 but you see my point) times more sensitive....
The folicle is not the hair....it's the shaft that the hair grows out of....so whatever you use massage that scalp and work that shit in there.......good luck bro...but I'm guessing you're screwed......they told you two months ahead of time so you had time to pass the test.......priorities my friend... Just for info purposes.....they will remove a chunk of hair and folicles about the size of a pencil from the back of your head, typically lower down your neck so focus your efforts there. They want 50-70 hairs so they get several folicles along with it......it's taken to the lab, dissolved in solvent and tested..........go look up the testing limits as I forget what the picogram per what is exactly.......I want to say picogram is 1/100,000th of a gram but I' won't swear to it. I can tell you for certain that urine testing has three levels 20, 50 and 100 nangrams per millilitre.......with 50 being the most used......I think the 100s are for outfits that know guys burn on occasion so they can't hire enough people that can pass the 50 test. The 20 test is for DOT regs.....I had to pass that to get my CDL...Ok I looked it up it's 1 picogram/mg for the test and .1pg/mg for the confirmation.......so if you flunk the test and the confirmation needs 10 x less....well,,,,,let's just hope you pass.
They do say it's less accurate for mj than other drugs, but I think that's old info. It is designed to catch the occasional user of drugs that are quickly out of the blood and urine........everything but MJ is out of your urine in 15 days or less....I took me 66 days to be able to pass a UA at the 50 ng/ml rate and another two weeks to pass the 20........ I always used urine luck quick fix for testing when I was in construction with no problems....put on the rig, they would walk up, hand you a cup and say fill it......on the spot....so no way to swap samples.....I worked either 7 on/7 off or 14 on/14 off so you could burn one on your first day off and pass the test when you went back on hitch........better than nothing.....