GEEESH. I'd be freaking out too. I thought I heard that the dying of hair does nothing to conceal your drug usage and besides, they could take the hair from anywhere on your body. I'm not really educated on the hair tests as I know I've never had to take one but I've heard they can tell the types of drugs you've used in the past several years, with hair. The longer the hair, the more years they can go back? I don't know about the shampoo you speak of....maybe someone with more experience can respond and help you out or maybe like FakeBoobsRule said, do a search and you'll find answers to help you get the job. Good luck.