Although there may be many hair follicle shampoos on the market that claim they can help to pass a drug test, these shampoos do not work. As of 2015, there are no commercial adulterant products that can greatly affect the results of a hair drug test, as noted by Omega Laboratories. The main reason these shampoos do not work is because a hair drug test involves examining the molecules found inside the hair shaft.
Most hair follicle shampoos are either maskers or cleansers. A masking shampoo for drug testing is said to work by coating the hair with masking chemicals. However, this technique does not work because laboratories that perform hair strand analyses wash the hair sample prior to testing it for drugs. Similarly, using cleansers, hair dyes, hair bleach or other hair processes does not significantly affect the outcome of a hair drug test result, as noted by Craig Medical Distribution Inc.
As of 2015, hair follicle testing is very accurate when compared to other types of drug tests, such as a urine sample, as noted by Omega Laboratories. However, this test can detect drug use for a period of up to 90 days. Hair follicle testing involves taking a sample of about 50 hair strands from the scalp line near the crown. Laboratories that perform hair drug testing screen for five different types of drugs, including cocaine, opiates, marijuana and amphetamines.