You failed a drug test hair for cocaine how long do you have to wait before you take another hair drug test?

It depends on a NUMBER of factors as with hairtest. how much and when . if it is used in th epast 100 days it will show if it was more than 100 and not allot it will not show . no wthis is assuming your hair is 1.5" or longer if it was used 80 days ago and your hair is .5" than it i snot in th ecollection window . IF it is in the window the only way to get it out is with a product called hair razor . do not listen to idiots who talk about propalyn glycol and bleach .

i am a lab tech and i know what im talking about