Most hair follicle tests are only given for parole or custody cases or for highly sensitive jobs but they are becoming more common for pre employment drug testing all the time.  Hair tests are gaining in popularity because they are harder to pass and can provide a more accurate portrayal of the substances ingested by the person that is being tested over the previous three months. The ninety day timeline is derived from the average rate of hair growth on the human head.  Your hair grows approximately one half inch per month and the testers normally take an inch and a half follicle length from the scalp.

If you think that you are going to get your hair cut to about a quarter inch of hair on your head and pass the test because your hair is too short then think again.  The testing facility will take a sample from your armpits or chest hair (for men) or they may give you a blood test.  The hair follicle has many layers and the metabolites from the drugs ingested are detected in the cortex of the follicle. The outer layer of the hair follicle shaft is known as the cuticle.  Inside the cuticle is the cortex and inside the cortex is the medulla.  Toxins, like THC metabolites will be stored in the cortex of your hair follicle.

There is constant blood flow into the hair follicle but no blood flow out of the follicle.

(To Be Continued)