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Marijuana in My Hair: The Science behind It

When you smoke a joint, you are living for the moment. You can forget all the stress in the world, ignore all the regrets and remain unaware of the uncertainties of tomorrow. But everything will change the day after. It will mark the first day of the 90-day window where you can test positive if you subject yourself to a follicle screening. It can screw up your job or your life in general.


For people who are looking for a new job, the 90-day window will be very bad. There is nothing much you can do about this problem. The follicle drug testing is one of the most common methods used by a lot of companies and government agencies to detect the presence of components in their staff or employees. It is used to identify drug users because it is time-intensive and less invasive compared to blood and urine screening.


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The widespread use of this method is quite controversial because research shows that it used to show a lot of false positive results. Usually, the test suggests that an individual will test positive for cannabis, even if they did not actually consume the drug and just exposed to visible smoke. While people who make the policy will decide whether it is a fair way to evaluate any use, it does not hurt to know the process involved in this test method and how it works, if it really works.


How do cannabis get in the hair?


When an individual smoke, eat or eat cannabis-infused products, all they really do is facilitate the release of THC or the drug’s active compound into your system. Once they are inside your veins, the cannabinoids will ride the bloodstream to the cannabinoid receptors on the cells where components like THC exert and bind their effects. During this process, the cannabinoids – the metabolites of THC that most tests are looking for – enter our blood vessels.


These blood vessels are what is feeding the scalp of our hair with nutrients. At the interface between the blood vessel and the follicle cells or papilla, tetrahydrocannabinol jumps between that gap and enter the matrix where and the hair grows. For the next couple of days, the hair from your follicles will sprout upward carrying tetrahydrocannabinol. Everything from here is fair game when it comes to drug screening for the next 90 days or three months.


How long do the drug components stay in the follicle?


Usually, cannabis can be detected in the follicle for the next 90 days after the drug was ingested. The calculated time frame is based on how long the hair grows from root to tip and past the scalp. It takes into consideration the hair part that testing laboratories use as a sample. According to experts, it will take five to ten days before the hair will push out drug components past the scalp for the world to detect.


During a hair follicle test, hair samples are taken one and a half inch from the scalp, and since it grows at a rate of half an inch every month, the user will have 90 to 120 days or about three to four months to be clear of any drug components. Within this window, the user can use top detox shampoos or detoxifying chemicals to remove any traces of components and toxins.


How does this method detect any drug compounds?


Once the hair is collected, it is washed properly to remove any external and unnecessary contaminants like dirt or bugs. It is the chopped into small pieces and digested in a solution that is designed to break it into its components (protein keratin with another compound that makes their way into the shaft).


Traditionally, the hair with a chemicals is put through an enzyme-linked immunosorbent assay test, a procedure that uses certain antibodies to bind to the targeted molecules of choice – in this case THCA, a metabolite of tetrahydrocannabinol or THC. In cases of positive tests, another set of samples of the same, it is put through a confirmatory test that a technique called GCMS or chromatography and mass spectrometry.


The technique known as GC/MS/MS or GC/MS, is more accurate than the ELISA. It is a more involved technique that scans the sample for the molecular signature of THC or other targeted compounds. The final chemical compounds in a sample give the final result.


The confirmatory level of THC metabolite that most laboratory uses is 0.1 picograms per milligram of the sample. Anything that is above that level pretty much confirms that the subject used cannabis in the past 90 to 120 days or three to four months.


Click here for an interpretation of cannabinoids in the workplace.


Are there any testing errors that can occur in this method?


There a lot of different variables in follicle drug testing for cannabis or marijuana that makes it a controversial method to decide whether the individual is using an illegal substance and fit for the job. As we mentioned above, a false positive result is very possible.


It is still not clear whether samples can incorporate cannabis-derived components after merely being at the same place as the cannabis smoker. Color or the hair melanin component seems to help alter the sensitivity of the screening test, with lighter -colored hair being less sensitive and the darker ones being more sensitive to the follicle drug screening.


According to a studies from SAMHSA, an agency working closely with issues regarding drug or alcohol abuse and mental health. There are also some concerns when it comes to gray hair usually turning up a false positive in the result. Although there is research that explains why it is always happening, further studies are needed to explain this phenomenon adequately.


And lastly, there is this issue with the growth of hair. Not everyone has the same growth rate, so it is possible that the hair can test positive for drug use even though the 90 to the 120-day window has already passed. In this case, the compound does not leave the hair after the date. The drug component stays in the follicles as it will grow back. The only way to get rid of all traces of THC 100% is to cut it off entirely.


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