How far back does a hair analysis show marijuana use?

"Hair testing is quite accurate and can go back 6 months or longer, showing any controlled substances used in a sort of timeline. As hair grows out, any drugs used are encased in the hair shaft, so the longer the hair, the longer back in the individual's drug history the lab can detect. Most legitimate testing facilities, however, only use hair within about 3-5 cm of the scalp, and discard the rest. This limits the detection history to about 90 days, depending upon the rate of growth of the individual's hair. Some people attempt to circumvent this through shaving their heads. In the absence of the required amount of hair on the scalp, body hair can be used as an acceptable substitute. Additionally, for pre-employment hair testing, the inability to obtain a sample may be grounds for not hiring the individual."

How far back does a hair analysis show marijuana use?

5 years

How far back does a hair analysis show marijuana use?

i heard it was for life.

How far back does a hair analysis show marijuana use?

a long time.

How far back does a hair analysis show marijuana use?

for however long your hair is. To remove all evidence from your hair, shave it off.

How far back does a hair analysis show marijuana use?

As long as you have that hair

How far back does a hair analysis show marijuana use?

For as long as your hair is. If you want it to not show up on your hair, don't smoke for a month and then shave your head.

How far back does a hair analysis show marijuana use?

hair analysis shows every drug you ever used...including marijuana....forever!! As long as they pull it from your belly....hair off head....not forever,,,

How far back does a hair analysis show marijuana use?

Actually, it only goes back to 6 months because after that time, enough cells have died off in the shaft to no longer carry the chemical residue.

How far back does a hair analysis show marijuana use?

It would depend on the length of your hair. Longer hair would show use over a longer period of time and the reverse of short hair.

How far back does a hair analysis show marijuana use?

7 years

How far back does a hair analysis show marijuana use?

Hair analysis is said to be able to detect drug use over the previous three months or so and can even establish a timeline of use. In contrast, the range of urinalysis detection is much shorter. Depending on the drug and many other factors, urinalysis detects drug use over only the previous two days to three weeks, and it's not difficult to cheat on urinalysis tests.

Unlike urine tests, hair tests can't detect recent drug use, since it takes several days for drugs to show up in hair. Urine tests easily detect marijuana, but have a tougher time spotting cocaine and heroin, while hair tests do just the opposite: they easily detect cocaine and heroin but have a tougher time with marijuana. In these ways, the two types of tests can be complementary.

If you are worred about this, shave your head!